Cool Breezes

Purpose: To understand how the skin cools the body

Background

Mammals are warm-blooded creatures and must always maintain a fairly constant internal temperature. A difference of a few degrees can mean the difference between life and death. When your internal temperature rise, your brain signals your blood to step up circulation to the skin. In this way, the heat is carried to the surface where it is lost by radiation. Your sweat glands also spring into action and your body begins to perspire through your skin’s pores. The sweat evaporates on your skin and you cool off.

Materials

• rubbing alcohol
• water
• 2 cotton balls
• 2 small plastic containers
• blindfold (optional)
• science journal

Procedure

1. Place a small amount of rubbing alcohol into one of the cups and a small amount of water into the other.
2. Either blindfold your partner or have him or her close their eyes.
3. Dip one cotton ball into the rubbing alcohol and the other into the water.
4. Dab one wrist with the alcohol and the other with the water.
5. Have your partner tell you which one feels cooler and record in your science journal.
6. Switch places and repeat.

 

Conclusion

1. Which liquid felt cooler? Why?
2. On very hot humid days why do you feel “sweaty?”
3. Doctors no longer recommend an alcohol bath to bring fever down? What are some possible reasons why?
4. How could you make your skin feel cooler using only water?