C's Experiment 2.1 Evaporation and Temperature

Experiment 2.1 Evaporation and Temperature

1. Purpose

It does not matter where a person is on the planet, water vapor is there. Whenever a person breathes in, they are inhaling at least a little water. Water left in the presence of air always evaporates. However, this evaporation process requires energy, which comes from heat. When a person sweats, the evaporation process requires body heat. In nature, this heat comes from the sun.

The purpose of Experiment 2.1 is to prove that this effect works, and demonstrate exactly how it does. I hope to show in this experiment how the evaporation process not only dries things out, it also cools them down.

2. Equipment

1. A small glass, like a juice glass

   
   

2. Two cotton balls

   
   

3. Tap water

   
   

4. Eye protection such as goggles or safety glasses

   
   

5. A bulb thermometer

   
   

6. A Ziploc^® bag

3. Procedure

1. I filled my small glass ¼ full of lukewarm tap water.

   
   

2. I let it sit out for 15 minutes.

   
   

3. Meanwhile, I spread out the Ziploc^® bag on the counter and placed the thermometer on the plastic.

   
   

4. I allowed the thermometer to sit for a while and then I read the temperature.

   
   

5. After waiting 15 minutes, I soaked the two cotton balls in the water.

   
   

6. I pulled the cotton balls out, squeezed out the excess water, and used them to surround the bulb of the thermometer.

   
   

7. I waited 3 minutes and then read the temperature, comparing it to the previous temperature.

4. Data and Observations

1. After 15 minutes the thermometer read 78 degrees

   
   

2. When I originally placed the wet cotton balls on the end of the thermometer, the temperature went up one degree to 79 degrees

   
   

3. The temperature on the thermometer gradually decreased

   
   

4. After three minutes, the temperature read 73 degrees

5. Conclusion

This experiment provided an excellent example of the water evaporation process. When the lukewarm tap water was allowed to sit out for fifteen minutes, this gave it time to adjust to the room temperature. At the same time that this was occurring, the thermometer was sitting on the piece of plastic. The significance of this is that the thermometer, too, was adjusting to the room temperature. Therefore, the first temperature that I read was that of the room.

Since the water adjusted to the room temperature, therefore, the cotton balls also were at room temperature. So, when the thermometer was surrounded by the cotton balls, it at first still read the room temperature. However, the temperature gradually decreased. The reason for this is that as the water evaporated, it cooled the cotton balls down. Given that the cotton balls were touching the thermometer, it cooled this down as well.

This experiment, as a result, is an excellent and accurate demonstration of how sweating cools the body down. When the water, functioning as the body’s ‘sweat,’ evaporated, it cooled the cotton balls, functioning as the body’s ‘skin,’ down.

An idea for further research would be to try the experiment in other drier/wetter climates with hotter/colder temperatures to note if the evaporation process requires a longer/shorter time period to complete.

6. Bibliography

Great Source. ScienceSaurus. Wilmington, MA: Great Source Education Group, 2005.

McKeeman, Lori. Physical Science Week 2 Class notes. Course website. Sept. 2008-June 2009. Science Dept, The Potter’s School. 9 Sept 2008

Wile,Dr. Jay L. Exploring Creation With Physical Science. Anderson, IN: Apologia Educational Ministries, 2007