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Question
Take a glass. Bring it near your mouth and blow hard on it. Do this two or three times. Does the glass look hazy?
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Solution
Yes, a mirror can also be made hazy in the same way. On blowing air from the mouth on the mirror, the mirror becomes moist. The air blown from the mouth is hot and the mirror is cold. The hot air that we breathe out contains water vapours which turn into tiny droplets of water when it comes in contact with the colder mirror. This makes the mirror moist and hazy. The air blown from the mouth is wet.
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