01-13-23, 08:34 PM
AN easy demonstration you can do on your kitchen table on how an evaporation layer will keep the water from warming up.
Take a cake dish 9x13. Fill it with water. Place a thermometer in one end of it. check the reading and write it down. Now take a hair dryer and blow it across the top of the water for 10 minuets. Be careful not to heat the thermometer directly. Now check the reading again.
Most hair dryers are 1,100 watts on high. You will find little or no change in the temperature. Depending on how warm the water is, it may even cool.
The thermal column progression is upward and not downward. Evaporation of the water keeps the layers below it cooler.
Now repeat this with water at 100 degrees. use the hair dryer on it again. You will drop about 10-15 degrees F. once again evaporation will cool the pan and it will also keep the energy from going into the water.
Take a cake dish 9x13. Fill it with water. Place a thermometer in one end of it. check the reading and write it down. Now take a hair dryer and blow it across the top of the water for 10 minuets. Be careful not to heat the thermometer directly. Now check the reading again.
Most hair dryers are 1,100 watts on high. You will find little or no change in the temperature. Depending on how warm the water is, it may even cool.
The thermal column progression is upward and not downward. Evaporation of the water keeps the layers below it cooler.
Now repeat this with water at 100 degrees. use the hair dryer on it again. You will drop about 10-15 degrees F. once again evaporation will cool the pan and it will also keep the energy from going into the water.