Snow in Science, Culture, and Climate


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AVALANCHE! Investigating snowpack dynamics and snow safety


Duration: 20+ minutes

Location: Outdoor (possible inside)

About: Students use an avalanche tilt board with snow simulants (flour, sugar, etc.) to investigate how slope angle, terrain type, snow layering patterns, and human and natural triggers contribute to the likelihood of an avalanche occurrence. 

Key understandings include: 

● Avalanches occur most frequently on slope angles between 25 and 60 degrees.

● The order in which weak, icy, and/or strong, heavy snow layers are arranged in the snowpack influences snowpack stability.

● Weather events such as heavy snowfalls, melting and refreezing, rain on snow, large temperature changes, and strong wind events affect avalanche risk at a particular place and time.

● The surface underlying the snow also influences avalanche risk.

● Under conditions of high avalanche risk, a human (e.g. a snowmachiner or skier) or natural (e.g. heavy dump of snow or strong wind storm that re-deposits heavy snow layers) triggers an avalanche.

● There are many good resources available to learn more about avalanche risk and outdoor safety.

AVALANCHE! Investigating snowpack dynamics and snow safety 


Snow safety. 2021. Our Winter World website.

Avalanche Encyclopedia. American Avalanche Association and National Avalanche Center. 

See especially: Avalanche (types of), Avalanche path, Anchors, Snow layer, Snow density, Stability, Weak layer, Depth hoar, Surface hoar, Rain crust, Sun crust,  Trigger, Remote trigger, Loading, Wind loading, Terrain trap, Whumpf, Danger scale


  • Avalanche tilt board – wooden board divided into three terrain type sections 
  • Model trees (color-coded) to insert into terrain board
  • Digital angle finder
  • Tarp to lay out under activity area to collect flour, sugar, etc.
  • Stuff sacks containing flour, sugar, and potato flakes
  • Toy snowmachine


1. Activity set up

This activity is messy in that it will result in several quarts to gallons of flour, sugar, and potato flakes sliding off of the avalanche board as the slope of the board increases. The kit includes a tarp to catch the materials. If your kit contains two boards and you plan to have students work in two groups, you can position one board at each end of the tarp.

One set up that has worked for us is to position the board at the end of a table or desk so that the bottom of the board (the end that will end up being the bottom of the slope) lines up with the edge of the desk or table. The board should be oriented so that as the back end is lifted, all three terrain types (trees, rocks, and smooth surface) are positioned on a slope.

Refer to the color coding on the bag to insert the small, medium, and large-sized model trees into the appropriately sized holes in the avalanche board. 

Remove the digital angle finder (clinometer) from the box and affix it to the Velcro on the board. If there is no Velcro on your board, attach the clinometer with duct tape along the side of the board, so that it will register the change in slope as the back of the board is raised up.

2. Avalanche demonstration orientation

Set up one or two activity stations (depending on whether your kit includes one avalanche board or two) as shown above. To start, leave the board lying flat on the table or desk.

Allow students to look at and feel the different snow simulant materials provided (flour, sugar, potato flakes). If you have already completed the snow pit study and examined different types of snow grains, ask the students for ideas as to what type of snow the different materials might best represent. Although the materials provided don’t behave exactly like the different types of snow one might find in a typical snowpack, we suggest making the following comparisons:

  • Sugar – Especially if it is coarse, sugar is crumbly and fairly large grained, so we can use it to represent depth hoar, which are large, faceted crystals that tend to form at the bottom of cold snowpacks.
  • Flour – Flour particles are much smaller than sugar grains, and flour tends to stick together more readily than sugar and form a denser layer than sugar. Flour will represent fairly stable, recent (but not fresh) snow that has had time to settle and pack together a bit.
  • Potato flakes – (optional) Potato flakes are flat, large, and feathery, and they could represent fresh snow crystals that haven’t started to break up and settle yet. Potato flakes could also represent surface hoar, feathery crystals that form on the surface under some conditions and may then be covered up when it snows again.

Depending on their prior experience and any introductory information that you have presented, students might have a hypothesis about what layering sequence(s) would be more likely to result in stable snowpack conditions than others. It is okay if they don’t however, as this activity is set up as an experiment and allows students to compare and contrast avalanche occurrence under different sets of snow conditions, slopes, and terrain types.

3. Avalanche activity procedures

A. Create your snowpack

1. With the avalanche board lying flat, affix the digital angle finder (insert batteries first), turn it on, and confirm that it reads 0 degrees slope.

2. Add the first layer of snow. Decide which type of “snow” you will use for the bottom layer of the snowpack. Use a scoop or (carefully) pour it from the bag to create an even layer across the entire board. If the amount of material that you have allows for it, the demonstration will be more effective if layers are approximately 1 cm or thicker. The layers may be different thicknesses.

Each time you add a layer, write down what type of “snow” you used or draw a diagram to help you remember the order of the different types of snow layers in your snowpack.

3. Add a second layer of a different type of snow. Allow different students to participate in each step. 

Write down or add to your diagram the type of snow you used for layer 2. 

4. Add a third layer of snow, so that your “snowpack” contains all three types of snow simulants.

5. If you have plenty of materials, you can continue to add one or more additional layers to your snowpack, recording the different types of snow layers from bottom to top as you go.

B. Increase the slope

6. One student will be in charge of slowly increasing the slope angle by raising the back of the board (the side farthest from the edge of the table). Another student will be responsible for watching the numbers on the digital angle finder as the slope changes. The other students are responsible for watching closely for signs of an avalanche starting as the slope increases. 

Optional: Ask students to make predictions as to which part of the board (smooth surface, rocky surface, or forested area) will experience an avalanche first (at the lowest angle).

7. The student in charge of increasing the slope starts lifting the back of the board slowly and as smoothly as possible. When students notice any part of the snowpack starting to crack or slide, they should call out for the person lifting the board to stop for a moment so that the person watching the angle finder can note the slope angle. After everyone has observed what is happening, the person in charge of changing the slope can begin lifting the back of the board up again.

8. Repeat this process, stopping anytime a new part of the snowpack starts to crack or slide and noting the slope angle.

9. At any point during the process, especially if there is a portion of the snowpack that has remained after the other sections have slid, you might drop the toy snowmachine or skier onto the slope as an example of how the weight of a human on skis or a snowmachine can sometimes trigger avalanches. You might also place either the snowmachine or the skier at the bottom of the slope (on the table or desk just between the lower edge of the board and the table edge) to illustrate how human recreationists can get trapped in avalanches that start on slopes above them.

4. Discuss results and implications for safe winter recreation

Please refer to background/reference materials listed above. Our Winter World program staff are continuing to work on this section of the lesson plan.

Consider inviting community members who have experience with backcountry snow travel (e.g. by snowmachine for hunting, or on skis, snowshoes, or by dog sled). If they are willing, ask them to share any stories about their experiences traveling outdoors in the snow, ways that they evaluate whether snow conditions are safe, and connections between weather patterns and snow conditions that they might have observed.

A few examples of online resources related to avalanches and snow safety:

Avalanche Problems Explained (video, run time 4:47). 2016. National Avalanche Center. 

Basic Avalanche Theory & Identifying Avalanche Terrain (video: run time 4:14). 2020. Altus Mountain Guides and EvoAcademy. 

Avalanche Safety Tutorial (interactive online activity). American Avalanche Association. 

5. Optional extension – snow pit study connections

You might have already done a snow pit study with your class. Making observations and measurements and analyzing information collected from snow pits is an important way that scientists can learn about snow. But snow pits are also very important to avalanche professionals and people who spend time recreating in the backcountry. Because their focus is on assessing snowpack safety and likelihood of an avalanche occurring, people who dig snow pits for these purposes perform some different tests and measurements that are not typically part of a scientist’s snow pit procedures.

Educators may reference our handout and student worksheets HERE:

Many videos and other resources explaining how snow pits are used to assess avalanche conditions are available online, including:

Snow Profiles (video, run time 12:44). 2021. American Avalanche Institute. 

How to Dig a Snow Pit. 2018. Backcountry Skiing Canada and Summit Mountain Guides. 

How to Perform a Compression Test. 2018. Backcountry Skiing Canada and Summit Mountain Guides. How to Perform an Extended Column Test. 2018. Backcountry Skiing Canada and Summit Mountain Guides.

WATER AND ICE: Density and molecular structure

WATER AND ICE: Density and molecular structure


The target age range for this lesson is middle school and up. For an elementary-appropriate version, see “Water and Ice: Investigating density through melting and freezing.”

Part I (optional): Students investigate the difference in density between water and ice by observing the change in water level in a glass of ice water before and after the ice has melted.

Part II: Students investigate the molecular basis of the lower density of ice than of liquid water by constructing an ice crystal lattice structure out of candy and toothpicks.

Recommended age/grade range: Middle school and up


References for step 6: Molecular geometry of ice crystal lattice 


Included in kits unless otherwise noted

Part I

● ice cube trays 

● clear plastic cups

● dry erase markers

● Teacher needs access to a water source for filling students’ cups. A pitcher may be helpful also.

● Teacher needs access to a freezer to make ice cubes.

Part II

● Molymod ice molecular model kit

● Toothpicks

● Gumdrops to represent Oxygen atoms*

● Mini marshmallows to represent Hydrogen atoms*

*Other objects may be substituted as available.


Part I: Investigating differences in ice and liquid water density through observation

1. Activity set up

At least one day before the activity, make enough ice cubes so that there is at least one (up to two) ice cube per student. Aim to make the ice cubes as similar in size as possible.

You may pre-fill the cups with water before class or have students fill them (a pitcher or large water bottle may be helpful) in class. 

2. Introduction to water and ice

Introduce or review phases of matter (solid, liquid, gas). 

Review the phases of water (solid=ice, liquid=liquid water, gas=water vapor). 

Introduce or review phase transitions. 

  • Ice-liquid water = melting (add heat)
  • Liquid water-vapor = evaporation (add heat)
  • Liquid water-ice = freezing (remove heat)
  • Vapor-liquid water = condensation (remove heat)
  • Ice-vapor = sublimation (add heat)
  • Vapor-ice = deposition (term is rarely used) (remove heat)

The differences in the physical form of these substances and the ways that they function are related to their microscopic, molecular structure. 

3. Optional: Water & ice density experiment

For detailed step-by-step instructions, see the lesson plan “Water and Ice: Investigating density through melting and freezing.”

Pass out clear cups and fill about half-way with water, and add an ice cube or two to each.

Have the students mark a horizontal line on the outside of the clear cup to indicate the starting water level. (You can help the younger students do this. Dry erase markers are included in the materials kit so that the lines can be rubbed off and the cups reused for the experiment in the future.) Use the same color marker for all of the cups so that you will be able to distinguish the starting water level from the ending water level.

Ask the students to notice where the ice cube is in the glass. Is it toward the top, or did it sink to the bottom? (Toward the top)

Ask them if they have any predictions about what will happen as/when the ice melts. Specifically, you can ask them if they think the water level in the cup will get higher or lower. 

Using a different color marker than they used to mark the starting water level, have the students mark a horizontal line on the outside of the clear cup to indicate the ending water level after the ice has completely melted. 

4. Discussion of results

Ask students to share their observations. Everyone should have noticed that the ending water level was lower than the starting water level.

Were students surprised by the results? If they made a prediction ahead of time, did the results match their prediction? 

What happened to cause the water level to go down? Which substance took up more space (had a greater volume): the ice cube, or the liquid that it melted into? (The ice cube)

Define/explain the concept of density. Density describes and measures how much material (matter) is in a given amount of space (volume)

H20 is different from most substances on Earth in that the solid form, ice, is less dense than the liquid form. This is because of the “lattice structure” that is formed by the arrangement of the bonds between the molecules.

Part II: The molecular structure of ice and water

5. Density and molecular structure

Display the assembled Molymod molecular model of the ice crystal lattice structure. 

  • Explain (or ask students to deduce) which model components represent Hydrogen atoms and which represent Oxygen atoms. The chemical symbol for water is H20, which is an abbreviation for two Hydrogen atoms and one Oxygen atom. The model shows how ice is made up of a structure where the bonds between the atoms are in a definite and repetitive arrangement called a lattice. 
  • Ask for ideas about how the atoms might be arranged differently in liquid water. Then demonstrate by dissembling the molecular model into its component H20 molecules. Illustrate that when water is in the liquid form, the molecules are free to move around and shift positions with respect to each other, and that they can be much closer together than in the ice lattice. 
  • Draw connections between the concept of density and the differences between the molecular structure of liquid water and ice.

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6. Geometry of water molecules and hydrogen bonds in the ice lattice

Challenge the kids to build their own ice molecular lattice using gumdrops for Oxygen atoms, mini marshmallows for Hydrogen atoms, and toothpicks for Hydrogen bonds. (Other objects can be used as available.)

Use the Molymod model as an example. Coach students to identify which of their materials match which parts of the model.

This activity will probably be more educationally beneficial and more relevant if the students have learned some molecular chemistry first (e.g. atoms and the periodic table, atomic weights, protons, neutrons, electrons, valence electrons, valence levels, covalent and ionic bonds, polar and nonpolar molecules, hydrogen bonds).

Detailed instructions for making the candy & toothpick model need to be written/provided. 

Key elements of the resulting structure are:

● An individual H20 molecule consists of 2 Hydrogen atoms covalently bonded to 1 Oxygen atom

Diagram, schematic

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● In an individual H20 molecule, the angle formed by the two Hydrogen atoms is 104.45 degrees. For the purposes of the student-made models, the angle can be approximate as long as they support the structure. 

Diagram, schematic

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● Tetrahedral shape of 4 Hydrogen atoms around each Oxygen atom, 2 H covalently bonded and 2 H hydrogen-bonded to each O, repeating structure


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● Molecular basis of hexagonal symmetry will be visible: Ring of 6 H20 molecules that is “dimpled” or “folded” (Refer to model.)

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Optional questions for additional discussion

● Discuss “real life” observations of what happens when liquid water freezes and expands and vice-versa. (E.g. polygonal patterns on the tundra form due to water that freezes in cracks in the ground and pushes the surrounding earth up. Pingos form when underground water freezes and expands, pushing the surrounding earth up. When frozen water in the soil – permafrost – thaws out, the liquid water takes up less space, so we get sinkholes and our buildings settle into the ground.)

● Discuss the consequences for life on Earth if solid water (ice) were more dense than the liquid form, as is true for most other substances. (E.g. rivers would freeze from the bottom up, and fish wouldn’t be able to overwinter; we couldn’t ice skate etc. until a pond or river was frozen solid throughout its whole depth)



Students capture falling snowflakes, observe with hand lenses/cell phone microscopes, draw/describe snowflake types and hexagonal symmetry, and preserve snowflakes by casting in superglue. Ideally, this activity will be done when it is snowing out. If that is not possible, observations can be based on snow on the ground, if the latest snow is relatively recent and if it has not been significantly changed by melting, rain on snow, strong winds, or other conditions that would destroy the snow crystal structure.


Ken Libbrecht – Snowflake Science: A Snowflake Primer – 

Ken Libbrecht – Types of Snowflakes chart – 

Ken Libbrecht – The Snow Crystal Morphology diagram (explanation of the Nakaya Diagram):


● Black velvet snow catcher sheets

● magnifying glasses

● cell phone microscopes

● Nakaya diagram handouts – laminated

● Snow crystal types charts – laminated

● Small paintbrushes

● Superglue (thin, liquid type – not gel)

● Microscope slides and cover slips


1. Activity set-up

At least 30 minutes prior to beginning the activity, place snow catcher sheets, paintbrushes, and slides and cover slips outside. This will allow them to cool down so that snowflakes don’t melt upon contact with them.

2. Introduction: What are snowflakes?

Definition of precipitation

What types of precipitation have you experienced or heard about? 

What types of frozen precipitation – forms (snow, sleet, freezing rain, graupel, hail)

Snow is special in that it is formed from water vapor that freezes in the clouds without first passing through its liquid phase

In order for this to happen, there must be a tiny speck of dust, bacteria, or some other type of tiny particle in the cloud. Water that is in its vapor form in the clouds starts to freeze onto the particle. (The particle around which a snow crystal forms is called a condensation nucleus.) The water vapor freezes in a special, orderly pattern, called a crystal. Once a snow crystal forms, it continues to grow as it moves around in the cloud, eventually falling from the sky and landing on the ground.

Watch Ken Libbrecht falling/growing snow crystal animations. 

When we see these crystals falling from the sky, we usually call them snowflakes. Snowflakes can be individual snow crystals, or they can be clumps of snow crystals stuck together.

Snow crystals can be different shapes and sizes, but they all have six sides or arms. (Sometimes when we find them they are broken, so we can’t see all of the arms.)

Look at snow crystal types chart. 


We are going outside now to observe snowflakes. We’ll do this by catching them on velvet and looking at them through magnifying glasses and cell phone microscopes so we can see all the details. 

When you are looking at the snowflakes that you catch, pay special attention to these things:

● Is it a single snow crystal or a clump of crystals stuck together?

● If it’s a crystal, what shape is it? How would you describe it/what does it remind you of? Which of the snow crystal types on the chart does it look most like?

● Can you see/count 6 sides or 6 arms, depending on the shape of the crystal?

Observing crystals.

3. Outdoor Session – catching and observing snowflakes

Pass out velvet snow-catcher cards and magnifying glasses (cell phone microscopes optional)

Place snow crystal types cards in accessible location

4. Explain procedures for making snowflake “fossils”

Refer to Ken Libbrecht activity sheet/web page: 

Preserving crystals using superglue.

5. Snow crystal stories: Messages from the sky

Snow crystals aren’t just beautiful, but they provide information about the conditions under which they formed in the clouds. Certain types of snow crystals form under different conditions. 

What types of snow crystals did you observe during our observation session? Refer to snow crystal types chart: 

Ukichiro Nakaya was a Japanese scientist who lived during the 1900s. He studied how different temperature and humidity (moisture) conditions in the clouds influence the types of snow crystals that form. He created a diagram to explain this relationship, and it is referred to by scientists today as the “Nakaya Diagram” in his honor.

Pass out copies or display on overhead the Nakaya Diagram from Ken Libbrecht:

Provide an orientation to diagram axes (temperature and humidity) and explain what it shows. (Note temperature scale is given in both Celsius and Fahrenheit.) Read an explanation here:

Ask students to find the snow crystal on the diagram that best matches the type they observed.  Coach them through the process of determining what the temperature and humidity conditions were like in the cloud where and when this snow crystal formed.

EARTH’S FRESHWATER RESOURCES: Snow as a water source


Students observe various forms of water (clouds, Greenland ice sheet, oceans) in a photo of the Earth from space and watch a teacher-led demonstration illustrating the distribution of Earth’s water resources, emphasizing the very small amount of Earth’s water that is fresh water and available to humans and ecosystems. 

This activity is an abbreviated version of several related lessons from the National Oceanic and Atmospheric Administration (NOAA) addressing water resources, water use, and water conservation.


Freshwater Availability lesson plan. No date. Precipitation Education, Global Precipitation Measurement Mission, NASA.  

Earth’s Water lesson plan. No date. Precipitation Education, Global Precipitation Measurement Mission, NASA. 
Where Is Earth’s Water? 2021. USGS Water Science School, U.S. Geological Survey.


Included in kits unless otherwise noted

● NASA photo of Earth from space, laminated

● measuring cups (1 x 2 cup measure, 1 x ½ cup measure)

● ice cube trays (2) – packaged with ice and water activity materials

● optional: simple water cycle diagram poster

● 5 gallon bucket full of water.

● Optional: School can provide a globe.


1. Engage/activate prior knowledge

Ask students to think about the lesson topic by posing questions such as “What are some of the ways that you use water everyday?” and “Where does the water that you use come from?” (from NASA Freshwater Availability classroom activity)

2. Observing water on planet Earth

Display Earth “blue marble” photo. (Photo source: NASA Freshwater Availability classroom activity)

Ask students to make observations and share what they notice with the group (when called upon, in an orderly fashion!). Draw their focus to WATER in the image. What are the blue areas? (Oceans, which are made up of water.) 

One of Earth’s nicknames is the “Blue Planet.” Why do you think this is? What makes it the blue planet? (About 70% of Earth’s surface is covered by water, which appears blue.)

But not all water appears blue in this photo. What are the white swirled areas? (Clouds, which contain water droplets or ice particles.) What about the solid white area in the upper right portion of the photo (Snow on the Greenland ice sheet – water in its solid forms.)

Water is one thing that makes the Earth so special among all of the planets. All living things need water to survive. As far as scientists know, water is not present on most planets.

3. Introduction to freshwater as a limited resource

Referring to the photo, ask if we would want to drink the water in the oceans? Why or why not? (No. It is salt water, and it does not help our bodies the way that fresh water does. Most living things can’t use salt water for survival. Similarly, farmers can’t use salt water to water crops.)

Introduce the idea that even though there is a lot of water on Earth, most of that is salt water that is in the oceans. 

It turns out that even though there is a lot of water on Earth, it’s mostly (97%) salt water. The amount of fresh water is only a small portion of the total water on Earth (3%), and that is the only water that people and land-based ecosystems can use.

4. Visually represent the distribution of Earth’s water resources

The following demonstration is adapted slightly from the NASA Global Precipitation Measurement Mission lesson plan, “Earth’s Water.”

The demonstration starts with a 5-gallon bucket filled with water. Tell the students that this represents all of the water (100%) on Earth.

We just learned that most of the water on Earth is salt water; the rest is called freshwater. We are going to focus on freshwater. Remove two cups of water from the bucket (in e.g. a liquid measure). These two cups represent all of the freshwater on Earth, which makes up 3% of Earth’s total water supply. Move the bucket representing the oceans out of the way, since we are only considering freshwater from now on. 

Ask students to share ideas about where/in what forms freshwater can be found on Earth. Suggestions might include lakes, rivers, glaciers, snow fields/ice, permafrost, aquifers/underground, as water vapor in the atmosphere/in clouds. Guide them toward identifying polar ice caps/glaciers as containing water in its frozen form. 

Remove ½ cup of water from the 2 cups of water representing all freshwater. Pour the remaining 1 ½ cups of water into an ice cube tray. The 1 ½ cups of water in the ice cube tray represent the amount of freshwater that is stored as ice in glaciers and polar ice caps (and therefore not available for use by humans). 

Focus on the remaining ½ cup of water. This represents the liquid freshwater that is in the ground, surface waters (rivers & lakes), and water vapor in the atmosphere. So if the 5 gallon bucket represents all of the water on Earth, this half cup shows how much of that total (1%) is freshwater that is available to use.

Optional: Explain that not all of the ½ cup of water is clean and usable by humans (for consumption). Use an eye dropper to remove one drop of water from the ½ cup. This drop represents the amount of freshwater that is clean and available for humans to use.

5. The sources of freshwater

We have learned that living things need freshwater to survive, and that besides the freshwater that we need to drink, cook, and wash, humans use freshwater for growing the food that we eat, generating electricity (hydroelectric power), making just about anything that we buy and use from paper to clothing to cars (Isaiah, 2014).

We have also learned that only a small amount of Earth’s total water can be used by humans for these things.

So where does the water that we use come from? (Lakes, streams, groundwater) And where does that water come from? (Rain, snow)

Header image: Courtesy NOAA

FEET AND FLOAT: Exploring an animal adaptation for life in the snow


Students learn about some animal adaptations for life in the snow by comparing features of pairs of similar animals that live in different environments. They explore their local area, searching for and learning to identify animal tracks in snow using a field guide. Using life-size stencils of selected animals from Alaska and other areas, students calculate the foot-load or weight-load of different animals and notice that animals inhabiting the snowiest environments tend to have lower foot-load values than those in less snowy environments. They experiment with the relationship between body weight, surface area, and depth of sinkage in snow by measuring how deep they sink in snow with and without snowshoes. 

This set of activities includes many options; teachers can choose to do some or all of the activities according to students’ ages and interests and time available. 

These activities complement “Feet, Float, and Physics: Exploring an animal adaptation to life in the snow,” an interactive online learning module for 6th grade and up available on the Our Winter World project website at: We encourage you to try it out with your students and share your feedback with us via the online comments form.


Snow and Living Things: Animals. 2020. Our Winter World website. 

Blending In.

Getting Around. 

Feet, Float, and Physics: Exploring an animal adaptation to life in the snow. 2021. Our Winter World website. 

How have plants and animals adapted in your area? UA REACH Curriculum, Unit 13: Your Environment, Lesson 13 – Grade 6. 2015. University of Alaska K-12 Outreach. 

Folding Animal Track Pocket Card to download and print. Alaska Department of Fish and Game. 

Why are my feet so big? Lesson plan. 2020. Alaska Department of Fish and Game. (Contact Fairbanks Office for information)

Materials :

Materials necessary for activity.

Our Winter World: Animal adaptations to living in the North (PowerPoint presentation file on flash drive in materials kit)

● Animal Tracks of Alaska field guides (4)

● measuring tape (dual metric/imperial scale) (2)

● clear 1 inch x 1 inch gridded acrylic boards (4)

● dry erase markers (1 set, assorted)

● dry erase cleaning fluid (1 bottle)

● Set of animal track stencils (assorted)

● graph paper (choice of 1 inch x 1 inch grid or 1 cm x 1 cm grid)

● snowshoes (1 pair)


1. Introduce animal adaptations to northern environments

Read instructions on first slide of PowerPoint presentation, then display PowerPoint presentation, moving animal photos to the appropriate columns according to student input. (If easier, you may also print the presentation, cut out the animal pictures, and ask students to sort them manually according to each characteristic, revealing the animals’ geographic range after each sorting task.) 

Tell the students that the rest of the activities in this lesson will focus on animal feet. What did they notice about the size of more northerly animals’ feet in comparison to similar animals from more southern/less snowy locations? Animals inhabiting very snowy environment tend to have larger feet compared to their body size and weight as compared with animals inhabiting less snowy environments. Ask for suggestions as to how this might help animals succeed in the north, and in the snow in particular? (Larger feet relative to body weight results in lower foot-load or weight-load, which means that the animal exerts less pressure on the surface of the snow than would a heavier animal or one with smaller feet. This helps these animals “float” on top of the snow better, making it easier and less energy-intensive for them to travel from place to place in winter.)

2. Outdoor exploration: Identifying and measuring animal tracks 

Ask students to share stories about what animals they have seen lately and about different types of animal tracks they see in the area and can identify. Guide them in browsing though the animal track field guides, coaching them to interpret range maps, gait patterns, dimensions and labels, and any differences between front and hind feet or juvenile and adult tracks.

Optional: Allow students to take photographs one or two pages of the field guide with their phones so that they can refer to the pictures in the field. OR, if time allows, make photocopies of selected pages of the field guide for tracks that you are likely to find near your school and create half-sheet sized laminated track cards that can be taken out in the field.

Go outside to explore and find animal tracks, identifying what type of animal made the tracks when possible. Note how deep the animal tracks are in the snow, and estimate how recent the tracks are based on the most recent snowfall event.

Optional: Try tracing a good track or set of tracks using the clear acrylic gridded board. To do this, lay the board, grid side down, on top of the track. If the snow is very new and soft, the board might sink in and ruin the track. If it stays in place and  you can see the track through the clear board, however, use a dry erase marker to trace the outline of the track on the plain acrylic (plexiglass) side of the board. Take the board inside and set it down so that the plastic grid is face up. Count the number of 1 inch squares that fall within the track outline that you drew. One method that is helpful for finding the total area of the track is to count every square that is at least half inside the outline of the track. Don’t count the squares that are less than half inside the track outline. The total number of squares that you count will add up to the area of the track in square inches.

Snow: Tiny Crystals, Global Impact Museum Exhibit Walkthrough

HOW MUCH WATER IS IN SNOW? Snow Density and Snow Water Equivalent


This activity may be done in conjunction with the snow pit study or as a separate lesson. Students use a snow sampling tool of established volume to explore snow density and snow-water-equivalent (SWE), the amount of water that is contained within a given volume of snow. Older students may calculate density and SWE values, whereas younger students will learn based on observation and comparison of different snow samples. 

In addition to gaining an introduction or applied context for the concept of density, students will gain an appreciation for the importance of snow as a water source.


What is SWE? Snow Water Equivalent. 2021. 

What is Snow Water Equivalent? No Date. Natural Resources Conservation Service, U.S. Department of Agriculture (USDA),the%20snowpack%20when%20it%20melts

Snow Density. Avalanche Encyclopedia. 2021. American Avalanche Association and National Avalanche Center. 


Included in kits unless otherwise noted

● snow sampling tools (black PVC tubes with handles) (2)

● foam stands for sampling tools (2)

● square wooden rulers for sampling tubes (2)

● large metal spatulas (2) – from snow pit study materials

● extendable utility shovels (2) – from snow pit study materials

● Snow density sampling how-to video clip LINKED HERE


1. Activity set up

At least twenty  minutes before starting the activity, place the snow sampling tubes and spatulas outdoors to cool down, so that they don’t melt the snow when they come in contact with it during the sampling process.

There are only two sets of sampling tubes. If you would like more students to be able to participate in the sampling activity at the same time, the activity can be done by collecting snow in other types of containers of known volume (e.g. plastic containers provided in the kit) with some modification in procedures. To be able to compare results from different locations, all students should use the same type of container and follow the same procedures.

2. Activity introduction and demonstration

If students have already completed the snow pit study, they will have noticed that there are differences in snow grain size and shape, how much the snow grains stick together, how much space there is in between the snow grains, and how hard or compacted the snow is among different snowpack layers. One characteristic of snow that scientists measure when doing a snow pit study is the density of the snow layers and the overall or bulk density of the snow at that location.

If students have already been exposed to the concept of density in math or science, ask a student to refresh everyone’s memory of what it means and how it is calculated. 

  • Density is equal to mass (usually measured in grams or kilograms) divided by volume (usually in cubic centimeters or cubic feet). 
  • If you have two objects of identical size and shape and one feels “heavier” than the other, it is the denser of the two objects. (It contains more mass or material within the same volume.)

You might also ask guiding questions to find out if students have an intuitive or experiential understanding of what density means and how it is different from but related to weight. 

Do students have any ideas about why someone would want to know about how dense the snow is? They are not expected to have answers in advance, but they might suggest implications for snow stability/avalanche risk/ “post-holing” in snow; determining which snow is best to melt for water; or other ideas from personal experience.

Another way we can think about density of snow is to think in terms of how much water it contains. Snow is made up of ice particles and air, so snow with more ice and less air is more dense than snow with less ice and more air. By collecting a known volume of snow and letting it melt, we can measure how much water it contained, which is related to its density. 

3. Activity procedures

If available, show the video clip of UAF snow scientist Charlie Parr demonstrating how to collect snow samples using the density sampling tool.

Note that only two students will be able to collect samples at a time if using the snow sampling tools. Designate two students to take the samples. Distinguish the tools by writing each students’ initials on a piece of tape and affixing the tape to the wooden handles of the tools.  You might suggest that the students collect samples from different layers in the snowpack or from different locations. 


  1. Use the shovel to cut vertically into the snowpack and remove snow from the area where you want to collect your sample. (See first snow pit study video clip for a demonstration.) Expose a vertical wall of snow at least 0.5 meters wide so that you can access it. Use a whisk broom or a gloved hand to brush loose snow from the exposed vertical surface so that you can see the locations of the different snow layers.
  2. Decide which layer you want to sample. The layer must be at least as thick as the diameter of the tool opening. If it is not thick enough, choose a different layer. 
  3. Insert the tool.
    1. If you choose to sample the top layer of snow, hold the wooden handle and insert the open end of the tool horizontally into the layer exposed in the face of the snow wall, being sure to keep it horizontal. Push it into the snow gently but firmly until the bottom of the black cylinder is flush with the face of the snow wall (with just the handle sticking out). 
    2. If you choose to sample a layer that is lower in the snowpack, use the shovel or metal spatula to gently remove (by scraping away) the upper layer(s) of snow. Once you have removed the snow above the layer that you would like to sample, repeat the process described in step 3.a.
  4. Use the large metal spatula to cut down vertically into the snow at approximately the location where you expect the open end of the tube to be located. (It might be helpful to use a ruler or tape measure to find the approximate location by measuring horizontally 13 centimeters back from the exposed snow wall.) Move the spatula around or cut down from the top again to try to find the position at which the spatula will cover the open end of the tube. Be sure not to push the spatula toward the tube opening, as this will push more snow into the tube, compacting it, which will affect the results.

The spatula can be done by the student who is still holding the sampling tube or by another student if more convenient. 

  1. When the spatula is touching the open end of the tube and covering the opening, gently and slowly pull the tube out of the snow horizontally, being sure that the blade of the spatula remains fully covering the opening of the tube the whole time.
  2. Once the tube has been extracted from the snow, slowly turn it to the upright position, keeping the spatula blade over the opening.
  3. Once the tube is in the upright position and being gripped by the handle, the spatula can be removed, and the sample should be carried inside, being careful not to spill any of the sample.
  4. In the classroom, insert the handle of the tube into the foam stand so that it remains upright while the snow melts.
  5. Place the tools in their stands on a stable surface close to a heat source, if possible, to speed up melting.
  6. When the snow in the tube has completely melted, insert the square wooden ruler, with the zero mark down, vertically into the center of the tube so that it touches the bottom. Then remove it. The part of the ruler that was submerged in the water will appear darker.
  7. Measure how deep the water was by referring to the darker colored, wet portion of the ruler.

4. Calculating density and snow-water equivalent

This portion is optional and is suitable for students who are more advanced in math, including geometry.


  1. Calculate the volume of the cylinder, which is the volume of the snow sample if collected properly. 

Volume of the cylinder in cm3 = pi x radius of the cylinder squared x height of the cylinder

Vcylinder = π x r2 x hcylinder

The number pi (π) can be abbreviated as 3.14

V = volume, r = radius, h = height

  1. Calculate the volume of liquid water contained in the snow sample.

Volume of water in the cylinder in cm3 = pi x radius of the cylinder squared x height of the water in the cylinder

Vwater= π x r2 x hwater

The number pi (π) can be abbreviated as 3.14

V = volume, r = radius, h = height

  1. Determine the mass of the water in the cylinder.

Water has a known density of 1 gram per 1 cubic centimeter (1 g/cm3). Therefore:

Mass of water in the cylinder =  volume of water in the cylinder times the density of water.

mwater= Vwater x 1 g/cm3

m = mass, V = volume, 1 g/cm3 = density of water

Density is represented by the symbol ρ (Greek letter rho)

  1. Determine the density of the original snow sample.

Density of the original snow sample = Mass of water in the cylinder divided by volume of the cylinder.

ρ snow = mwater ÷ Vcylinder

ρ = density, m = mass, V = volume

5. Comparing and discussing results

Compare the depth of water that resulted from the two different samples. Was there more water in one sample than another? Were the samples taken from the same snowpack layer or a different snowpack layer? If from different layers, which layer contained more water?

We can infer from the amounts of water that each sample contained whether one snow sample was more dense than the other. Which sample was more dense?

6. The importance of water from snow

References to help connect the activity content to critical freshwater resources from snow:

Importance of snow. 2020. Our Winter World website. 

Importance of snow: Supplying Water. 2020. Our Winter World website. 

Snow Program Overview. National Water and Climate Center,  Natural Resources Conservation Service, U.S. Department of Agriculture (USDA).
Program History. National Water and Climate Center,  Natural Resources Conservation Service, U.S. Department of Agriculture (USDA).



This activity reinforces the fact that snow crystals (which we often call snowflakes) have hexagonal (six-sided) symmetry. Students fold round paper and cut out their own six-sided snowflake designs. 

Recommended age/grade range: all ages!

Time required: 20 minutes


Ken Libbrecht – Snowflake Science: A Snowflake Primer – 

Ken Libbrecht – Types of Snowflakes chart –

Ken Libbrecht – Snowflake Photographs – 

Ken Libbrecht – Designer Snowflakes – 


Included in kits unless otherwise noted

● Circular white paper 

● Snow crystal types charts – laminated

● Scissors (provided by the school)

Watch how to fold paper snowflakes with Dr. Matthew Sturm from Our Winter World & Kerry McClay from Winter Wildlands Snow Schools!


1. Activity set up

Optional: You may choose to cut out a couple of snow crystals to show as examples or help provide ideas.

2. Introduction: Hexagonal symmetry

When we see these crystals falling from the sky, we usually call them snowflakes. Snowflakes can be individual snow crystals, or they can be clumps of snow crystals stuck together.

Snow crystals can be different shapes and sizes, but they all have six sides or arms. (Sometimes when we find them they are broken, so we can’t see all of the arms.)

Look at snow crystal types chart:

Practice finding and counting 6 sides & 6 arms of crystals depicted in the chart.

Introduce or remind students of the concept of symmetry. Because snow crystals have six identical sides/arms and an individual crystal looks the same no matter which side or arm is “up,” we say that snow crystals have hexagonal symmetry. (Show the shape of a hexagon.)

3. Paper snowflake activity

Today we’ll be cutting out our own hexagonally symmetrical snow crystals. 

Has anyone made a paper snowflake before? Let’s first look at some examples found online.

Optional: Look at paper snowflakes online or take a walking field trip to view paper snowflake decorations. Are there some designs that couldn’t actually be found in nature? Which ones? (Paper snowflake crafts are sometimes made with four- or eight-sides. These may be pretty, but snow crystals in nature only have six sides or arms. (Sometimes they can appear to be twelve-sided/twelve-armed when two snow crystals stick together or “aggregate” and then continue to grow as one….but their symmetry is always a multiple of six.) 

Display examples and coach kids through cutting out snow crystals.

Allow students to take their snow crystals home or use them to decorate windows or bulletin boards at school.

For students who want a challenge, show them (or encourage them to find online) photographs of specific snow crystal shapes and challenge them to create a paper snowflake that looks like the example.

Many different examples of photographs of real snow crystals can be found on Ken Libbrecht’s website. 

Step 1: use circular piece of paper

Step 2: Fold circle in half

Step 3: fold the halved circle into thirds

Step 4: figure out how you want to cut your snowflake and cut your lines

Step 5: Unfold your snowflake and see what you created!

If you run out of circular paper, see the following instructions for how to make six-sided snowflakes out of 8.5 x 11” paper:

Ken Libbrecht – Making Anatomically Correct Snowflakes: 

KarenHC, November 30, 2015. Instructions for making paper snowflakes – an easy tutorial. When Life is Good. [Retrieved 8/22/2021]

TRACK SOUVENIRS: Casting plaster animal tracks


Students make plaster casts of animal tracks found outside or create plaster imprints of animal track replicas. They gain practice observing the natural world closely, and create a memento they can keep without removing any objects from the natural world. 


How to make plaster casts of an animal track. 2011. MyNatureApps. 

Cabrera, Kim A. 2001-2007. Plaster Track Casting Procedure. 

Save Animal Tracks as Plaster Casts. 

Mangor, Jodie. 2021. How to make a plaster cast of animal tracks in the snow. Scout Life. Boy Scouts of America. 


Included in kits unless otherwise noted

● Plaster of Paris (2-4 x 4 lb. containers)

● Jumbo craft sticks for stirring/mixing plaster

● Gallon size Ziplock bags for mixing plaster and water

● 1-2” wide strips of cardstock or manila folder material for forming a ring or collar around the track to contain the plaster

● clothespin or paperclip to secure the cardstock/paper ring

● Spray bottle 

● School provides water for mixing with plaster and for use in spray bottle to set the track in snow before pouring plaster. 32 oz. Nalgene water bottle provided in kit should hold enough water for a couple of smaller tracks; a moose or bear track might require the whole bottle.


Refer to instructions in reference materials listed above. Note that different sources have different opinions and preferences for materials and methods. Try an approach that appeals to you! One thing to note is that if you are making plaster tracks in snow, it is worth lightly spraying the track with a fine spray of cold water before adding the plaster to help set the track. Also, mix some snow in with the water when mixing your plaster so that the plaster mixture doesn’t melt the track.

In case you aren’t able to find any good tracks to cast outdoors, you can make negative track imprints using the flexible track replicas provided in your kit. Your kit will contain either a) two caribou tracks and two wolf tracks or b) two wolverine tracks and two snowshoe hare tracks. 

Follow these steps to make negative impressions of the replica tracks provided:

  1. Use the paper bowls provided to mix individual portions of plaster and water. A mixture of two parts plaster to one part water is generally recommended.
  2. Fill the bowl about two thirds full with plaster-water mixture and continue to stir using a craft stick.
  3. When your plaster and water mixture is a good consistency (like thick pancake batter), smooth the top of it with a craft stick. 
  4. If you have access to cooking spray, you might choose to lightly spray the surface of the track replica before inserting it into the plaster. 
  5. Then, firmly press the track replica face-down into the bowl of plaster. Allow it to sit, undisturbed, for approximately twenty minutes. 
  6. After twenty-five minutes, lightly touch the plaster with your finger to test how dry it is. If it is fairly dry and stiff, attempt to remove the track replica from the plaster. 
  7. Your result should be an imprint of the track – just like what you might find in the snow or mud if you found an animal track outdoors. 
  8. Ideally there will be enough bowls that each student can make an imprint and take a bowl home; there is no need to remove the plaster from the bowl. They may choose to decorate the final product with paint or glitter or to add their initials, the date, and the name of the animal whose track they have cast.

Albedo Experiment


Students conduct a simple experiment to investigate reflection and absorption of visible light by dark and light materials. They learn that the term albedo refers to the ratio of how much incoming light is reflected by a substance and explore the albedo values of different types of surfaces on Earth. Based on the results of the experiment, they make inferences about the important role that snow plays in regulating Earth’s climate. 


Importance of snow: Cooling the planet. 2020. Our Winter World website. 

Snow science: Optical properties of snow. 2020. Our Winter World website. 

Changing Albedo Values. My NASA Data. Includes links to:

  • Earth’s Energy Budget Includes Albedo (Why does the Sun Matter for Earth’s Energy Budget? video)
  • When do albedo values change? (Climate Bits: Albedo video)
  • Why does NASA study albedo? (Global temperature anomalies from 1880 to 2018 video)

Albedo – Terrestrial Albedo. 09.03.2021. Wikipedia. 

Earth’s Energy Balance (online interactive simulation). 2021. University Corporation for Atmospheric Research (UCAR) Center for Science Education. 


Included in kits unless otherwise noted

Kits include enough materials so that four groups of students can do the experiment at the same time.

● Black felt pockets (4)

● White felt pockets (4)

● Dial stem thermometers (8)

● Clamp on lamps with reflector shades (4)

● 60 Watt Incandescent light bulbs (4)

● Schools might need to provide extension cords and/or power strips for lamps.


1. Experiment set up

Set up four stations. For each station, you will need a desk, table, or other flat surface; 1 black felt pocket; 1 white felt pocket; and 1 clamp lamp with light bulb. 

Lamps should be positioned so that they shed light on the surface below them, upon which the two felt pockets will be placed side by side. The lamps should be centered over the surface so that each pocket receives the same amount and intensity of light. If there are no good options for affixing the clamp lights above desk/table height, you can clip them to the edge of the desk and set up the felt pockets on the seat of a chair underneath. 

Felt pockets should be oriented so that the thermometer dial can be read easily while the thermometer stem is inserted into the pockets. 

Check to make sure the two thermometers at each station read within a degree or two of each other. If they don’t, refer to the instructions on the packaging to calibrate them so that they start at the same temperature.

2. Experiment introduction and hypothesis development

Introduce what the experiment will entail without presenting too much information about the underlying science. 

Ask students to develop a hypothesis based on their everyday life experience as to whether and in which direction they think that the temperatures will change (go up, go down, or don’t change) and whether and how the temperature changes will be different between the black and white felt pockets (e.g. one will go up, one will go down; both will go up but the black one more so than the white one, etc.). 

Ask students to write down their hypotheses in a notebook or data sheet and to including their rationale, whether based on life experience, knowledge of underlying scientific concepts, or intuition. 

3. Experiment steps

Students at each station should follow these steps in sequence:

1. Before turning the lights on, insert a thermometer into each pocket (one black, one white) so that the dial is facing them and the stem is fully covered by the felt. Ensure that the thermometers are placed in such a way that the lamp is centered over them, providing an equal amount of light to each pocket.

2. Read the initial temperature of both thermometers and record them in a notebook or data sheet.

3. Turn on the light. Without touching the materials, watch the thermometers for changes in temperatures.

4. After five minutes, check the temperatures, being sure not to touch the thermometers or remove them from the pockets. Record the temperatures in a notebook or data sheet, being careful to note which temperature is for the black felt pocket and which is for the white felt pocket.

5. If there is a substantial temperature difference between the two thermometers after five minutes, you can end the experiment. However, if there has only been a small change in temperature and/or if the temperature of one or both thermometers seems to be continuing to change rapidly, wait another three to five minutes and record the temperatures again.

3. Share and discuss results

Ask each group to calculate how much the temperature of the white pocket and the black pocket changed during the experiment by subtracting the starting temperature from the ending temperature for each. 

Compile results from all groups by having a representative of each group enter their temperatures in a whole class chart (e.g. created by the teacher on a white board) or by sharing aloud the starting and ending temperatures that they recorded for the white and black pockets. Note any discrepancies in results and check to find out if everyone followed the same experimental protocols.

Did the results support or conflict with their hypotheses? If so, do they have any thoughts about what might account for the results that they had not considered in developing their hypotheses?

If they haven’t already done so, ask students to share examples from their life experience that relate to the experiment. For example, if they have ever worn black or dark clothing versus white or light-colored clothing on a hot, sunny day, which color of clothing made them feel warmer? Has anyone had the experience of walking barefoot on black asphalt or lighter colored surfaces? 

4. Connecting scientific concepts: Explaining absorption and reflection

Refer to background/reference information.

Light is either reflected or absorbed by an object or substance. 

The word albedo refers to how much of the incoming light that an object receives is reflected by that object. More reflective objects have higher albedo values, and less reflective objects have lower albedo values.

Albedo values range from 0 to 1. An object that absorbs all incoming light and reflects none of it has an albedo value of 0. An object that reflects all incoming light and absorbs none of it has an albedo value of 1. 

5. Applying what we’ve learned: Albedo, snow, and Earth’s climate

Display an aerial photograph or photograph of the Earth from space and notice the different colors of Earth surfaces. Which areas would the students expect to have high albedo values and which would have low albedo values?


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6. Optional extension for advanced learners

A. Earth’s Energy Budget

Earth’s albedo is an important part of Earth’s energy budget, which describes the net amount of energy absorbed by the Earth based on its incoming energy and outgoing energy flows. Earth’s energy budget determines the temperature of the Earth.

This online interactive from UCAR Center for Science Education allows you to manipulate amount and brightness of incoming solar energy and the albedo of Earth’s surface and see how changes to those values affect Earth’s temperature: 

B. The electromagnetic spectrum and visible light

Teaching references:

NASA Science. 2021. Introduction to the Electromagnetic Spectrum (video). National Aeronautics and Space Administration (NASA). 

NASA Science. 2021. Visible Light (video). National Aeronautics and Space Administration (NASA). 

Butcher, G., Mottar, J., Parkinson, C.L., and Wollack, E.J. 2016. Tour of the Electromagnetic Spectrum. National Aeronautics and Space Administration (NASA).