Purpose
To demonstrate how sand dunes are formed.
Materials
- shallow baking pan
- flour
- meat baster
Procedure
- Cover the bottom of the baking pan with a thin, flat layer of flour.
- Use your hand to support the baster with its open end about 2 inches (5 cm) from the edge of the flour.
- Squeeze the bulb of the baster 10 times.
Results
The flour moves away from the end of the baster in a semi-circular pattern. The flour piles up close to the end of the baster.
Why?
The moving air leaving the baster has kinetic energy (energy of motion). The flour particles are small enough to be lifted by the moving air and carried forward. Some of the smaller particles move farther away, but most lose energy and fall, forming a mound near the end of the baster. As this mound builds, it blocks the movement of even the smaller flour particles that would have traveled farther. This demonstrates how sand dunes are formed.