# Learning Lesson: Go with the Flow

OBJECTIVE The students will discover that the faster air moves, the lower the pressure becomes within that flow of air. Create low pressure by blowing between two soda cans. 5 minutes Two (2) empty soda cans Level surface None None Tornado safety

Background

Bernoulli's principle states that in fluid flow, an increase in velocity occurs simultaneously with decrease in pressure.

Procedure
1. Lay the two cans parallel to each other, about one inch apart, near the edge of a level surface.

2. Put your face down near the surface and blow between the two cans.

3. It will take some trial and effort but eventually the two cans will roll together.
Discussion

The affect is Bernoulli's principle in action, named after the Dutch/Swiss mathematician/scientist Daniel Bernoulli. By blowing between the two cans, you are making the air between them move faster than the surrounding air (which is basically calm). The cans roll together as the higher pressure surrounding the two cans (away from the air flow) pushes the cans together toward the region of lower pressure.

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