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Activity

Friction: sledding

Summary: 
Test different materials on snow for how well they make a sled, and describe their differences in terms of friction.
Science content (2016 curriculum): 
Physics: Motion and Forces, Newton’s Laws, Gravity (K, 2, 6)
Science topic (2005 curriculum connection): 
Physical Science: Force and Motion (grade 1)
Physical Science: Forces and Simple Machines (grade 5)
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Materials: 
  • sledding hill, with an area where a short hill can be made for several students to sled side by side
  • plastic sleds, several of the same kind. We used magic carpets, rented at Mount Seymour sledding hill.
  • squares of material, roughly 0.5m x 0.5m, of varying roughness. We used smooth imitation-leather and rough felt-like cloth (they were two sides of the same material). Also snow pants can be used.
Procedure: 

Ask the students to sled down the mini hill on their plastic sleds to make the run smooth. Describe and practice walking up the side of the hill to get back to the top without walking up the area they are sledding on.

Distribute squares of other sledding materials. Ask the students if they think they will sled down on each material faster or slower than on their plastic sled.
Students sled down the hill multiple times, to get an accurate impression of whether the provided material is faster or slower than the sled. They many want or need to do the run on their sled again to compare.
Students exchange sledding materials until they have all tried all kinds.
Students can record results on the suggested worksheet, though we reviewed from our memories to avoid the complexities of writing in the snow.

Sit as a group in the snow, and material by material hear the results the students found, then look at the material and discuss why it is faster/slower than their sled.
Common results (though if your cloth type is different, your results may be different - then discuss according to your results):
The rough felt-like cloth should barely move at all. It has a very bumpy surface which gets caught up in the snow, generating a lot of friction (the surfaces get stuck in each other and stop them from moving past each other so easily).
The smooth fake-leather cloth will move a little, but not as fast as the sled. It has more ridges on it than the sled, which get stuck on the snow, generating some friction which slows it down.
Snow pants vary a lot as they are not so rigid. In interpreting results, you might want to discuss the folds in the pants, the smooth material that they are made of, the bumps of the seams in the cloth - in general more bumpy (little or large bumps in the cloth) slow things down i.e. make more friction.
Some magic carpet sleds have a rough and a smooth side. Students should be able to predict which side will go faster, then can test this out when they return to the main hill.

Grades tested: 
Gr K
Gr 1
Gr 2
Gr 3
Teacher: 
Carole Murray
Ingrid
Mari Matsuo
Teaching site: 
Sexsmith Elementary
Activity originally developed and delivered: 

Scientist in Residence Program, Vancouver.
Lesson plan at http://www.scientistinresidence.ca/pdf/physical-science/Force%20and%20Mo...