University of Virginia
Physics Department

Evaporation and Heat Engines

A Physical Science Activity

Student Activity

Materials

 

Procedure

  1. Pour the water into one cup and the rubbing alcohol into the other cup.
  2. Observe the two samples, and after several minutes note which liquid seems to have evaporated faster.
  3. Place a few drops of water on one hand and a few drops of rubbing alcohol on the other hand.
  4. Wave your two hands slowly through the air. Note any difference in how each hand feels. Does one feel cooler than the other?  

 

Questions

1. Which substance seems to have evaporated faster, water or alcohol? How can you tell?

 

2. When you waved your hands in the air, which felt cooler? Why did your hands feel cool?

 

3. Where did the heat come from that made the liquid evaporate from your hands?

 

4. Explain in your own words how the Drinking Bird keeps drinking.