Village Science - Teacher Edition


Snowmachine Tracks

Teacher Edition Contents

Skill, Tools, & Craftsmanship

Cutting & Drying Fish
Nails, Pegs, & Lashings
Falling Trees &
     Small-Scale Logging
Chainsaw Clutch & Chain
Ice Pick


Wood Stoves
Wall Tents
Insulation & Vapor Barriers
Gas Lamps & Gas Stoves


Piloting A Boat
Boat Design
Magnetos & Spark Plugs
Outboard Motor Lower Unit

Outboard Motor Cooling System
Snowmachine Tracks
Snowmachine Clutch
Winter Trails


  1. Put gasoline on a rubber band. What happens? Put a rubber band outside in the cold. How flexible is it below zero? Why aren’t tracks made of real rubber?

    Gasoline will quickly dissolve the rubber in a rubber band.

  2. Look at the different snowmachine tracks in the village. How do they compare in length and width? Do some have metal cleats? Do any have racing stars? Of all the different kinds, which is the most popular in your village?

  3. Measure the surface area of the tracks plus surface area of the skis of different machines. Compare the surface area to the weights given in the snowmachine specifications. How many pounds per square inch does each one represent? Are there relationships between the psi of trail machines contrasted with racing machines?

  4. Draw the patterns of the bottom of the tracks. Compare them. Compare them with four-wheeler tire patterns. Are there any similarities?

  5. Find old tracks around the village. Compare their thickness. Diagnose why each one broke (cracking, wear in certain places). Try bending a piece of track that has been out in the cold. Try bending the same piece of track once it has been inside for a while. How much difference is there? Speculate how much more power it takes to turn a cold track than a warm one.

  6. Carefully try to cut a piece of snowmachine track. Can you appreciate the technology that made it this tough?

  7. Ask the people in the village what they do when a track breaks far away from home.

  8. What uses have people found for discarded snowmachine tracks in your village?

    They make great walkways before the porch on a house. They aren’t slippery, and people clean their feet on them.

  9. Compare the suspension systems of the machines in your village. Do some still have bogie wheels? Talk to people that own the two different kinds. What are the advantages of each? Find a discarded slide rail. Does it look like it wore out because of snow or gravel? Try to cut it with a knife. Is it hard? What uses have people discovered for used slide rails? Inquire how much new slide rails cost and how hard they are to install. Identify the part of the track that slide rails run against. How is this different from the rest of the track? Are the bearings on the bogie wheels sealed bearings? What do you think happens when the seals go bad? What can you learn about increasing the life of bearing seals?

    Slide rail material is quite hard for a plastic. They are fairly inexpensive and are easy to change once the track is removed.

    Bearing seals? Stay out of water and dirt.

  10. Look at the skis on different machines in your village. Talk with people who use the plastic skins that fit under the skis. What do they say? What is the surface area of the average ski? Compare skegs on the different skis.

  11. Measure the distance between the skis on different machines. Is there a difference? If so, why do you think this is so? What do snowmachine owners say about skis being close together or farther apart? Is it important? If so, under what conditions?

    Wider skis are more stable, especially at high speeds.

  12. Talk to several people who have installed the sheets of plastic under the belly of the snowmachine. Do they notice a significant difference? Why did they install the plastic in the first place?

  13. When did snowmachines first come to your village? Ask the older people how they have changed over the years. What about them has improved? What about them has not improved? Why do they think machines are better than dogs?

Student Response

  1. Why wouldn’t a track made out of natural rubber last on a snowmachine in Alaska?

    It would stretch too much and be dissolved by gasoline and oil.

  2. Why are there nylon cords in the track as well as Kevlar?

    To keep the Kevlar from tearing

  3. What is the problem with a very large track?

    It takes a lot of energy just to turn it.

  4. What is the problem with a small track?

    It sinks deeply into the snow.

  5. What is the problem with a track that is too smooth? Too rough?

    Too smooth doesn’t have enough friction to pull a load or climb a hill. Too rough will dig in when traveling on powder snow.

  6. What kind of track would you want to operate in deep powder snow?

    High surface area

  7. What kind of track would you want for racing? For pulling big loads on hard trails?

    Racing: smaller track with cleats and stars.

    Big loads on hard trails: wider track with cleats.

  8. Skis are designed to have very little friction in a direction, and considerable friction in a direction.

    Forward, sideways

  9. What is the purpose of skis besides steering?

    Provide surface area to keep the machine on top of the snow as much as possible.

  10. Why do some people put plastic skins on skis?

    They greatly reduce friction and increase flotation.

  11. Why do some people have belly plastic installed?

    Reduce friction in deep powder and protect the belly.


  1. A machine weighs 375 lbs. The track is 15” x 47” in contact with the trail. The skis are 5” x 30” each with plastic shoes. What is the average psi of this machine on the surface of the snow?

    .373 psi

  2. A racing machine weighs 489 lbs. The track is 15” x 40” in contact with the snow. The skis are 5” x 24” each. What is the average psi on the surface of the snow?

    .582 psi

  3. A long track uses 25% more energy to turn than a short one. Turning a short track represents 9% of a machine’s effort. If Pete usually spends $350 a year on gasoline approximately how much is he paying for the convenience of having a long track?

    $7.87 not expensive at all.

  4. Having plastic ski skins and plastic on the belly of a machine saved 12% of a machine’s effort. They cost $75 to purchase. If Moxie usually spends $425 for gas on his trapline, will the plastic on the skis and belly pay for themselves in the first year?

    No. $51 is less than the original $75. But they will pay for themselves the next year. However the difference is in performance and handling, not just in gas savings.

Questions or comments?
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