Advertisements
Advertisements
Question
If the back of your hand is moistened with alcohol, you will find that it rapidly becomes dry. Why is it that while it is drying, your hand feels cool ?
Advertisements
Solution
Alcohol is a volatile liquid. It evaporates very fast by absorbing heat from surroundings. When our hand is moistened with alcohol, drops of alcohol absorb heat from the hand to achieve latent heat of vaporization and evaporate. As the hand loses heat to alcohol, it feels cool. This is an example of cooling by evaporation.
APPEARS IN
RELATED QUESTIONS
Why does a desert cooler cool better on a hot dry day?
Why are we able to sip hot tea or milk faster from a saucer than a cup?
Water in a dish evaporates faster than in a bottle. Give reason.
Why is heat energy needed to melt a solid ? What is this heat energy called ?
Define the following terms Condensation
Define the following term Freezing.
During summer days, water kept in an earthen pot (pitcher) becomes cool because of the phenomenon of :
Evaporation of water from lakes and river ______.
Look at Fig. 1.3 and suggest in which of the vessels A,B, C or D the rate of evaporation will be the highest? Explain.
Comment on the following statements:
Rate of evaporation of an aqueous solution decreases with increase in humidity.
