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Avalanche!

Investigating avalanches through experiment

Questions to consider
Extending the experiment

Equipment required

• a range of materials such as: peas, lentils, rice, oats, muesli, raisins, sand, gravel ... be imaginative!
• funnel held in a clamp
• length of tubing, guttering, or similar
• measure, such as a tablespoon, measuring cylinder or beaker
• squared paper

Method

1. Place the funnel in the clamp with the squared paper on the table top directly underneath the funnel, and record how high the funnel is above the paper.
2. Put a measure of the material to be tested through the funnel.
3. Note if there is an avalanche, and how big it is (you will have to decide what 'small', 'medium' and 'large' might mean in this context).
4. Record:
   • the area of the squared paper covered (you will need to decide how to deal with squares that are partly covered)
   • the height of the pile
   • the angle between the paper and the pile
5. Graph your results.
6. Repeat the experiment with different substances or mixtures of substances.
   • You could investigate a particular substance, then try mixing in a small amount of rice or raisins, say, to see what difference it makes if the added substance is dry or sticky.
   • What difference does the proportion of the added substance make?
   • Alternatively, you could investigate what happens for muesli or different size particles of sand and gravel. Again, be imaginative!

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Questions to think about

• When did avalanches occur?
• Do they relate to the area covered, the height of the pile or the angle of the pile?
• Is there a maximum area, height or angle for your pile?
• How does the substance used affect your results?
• What difference does it make if you use a small amount of another substance mixed in with your original substance?
• Where do the larger particles end up?
• How does the proportion of the other substance affect things?
• Does it make a difference how sticky the other substance is?

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Extending the experiment

• Instead of dropping substances vertically through a funnel, try dropping them down an inclined tube onto squared paper. How does this affect what happens?
• What difference does it make how high up the tube you put the material you are dropping?
• Can you think of a way to model the effect of snow fences and dams?
• What difference does it make if dams are perpendicular to the flow or inclined to it? Can you find an angle at which your dam is most effective?