Mint Windowsill Culture

I am growing mint plants for a science fair project. One day I watered my plants in the morning. When I got back from school, the leaves of the mint plant were dried out and wrinkled. I was wondering if that meant that I am not supposed to water the plants or did I do something else wrong.

Mints need a lot of water. If the plants sit on the windowsill with the sun shining and the heating system of the house going as well, the plants will dry out quickly and even get half fried in the sun. Mint also makes a very extensive root system so that very soon there is not much soil left in the pot but just lots of roots. When you water such a pot not much water can be taken up by the remaining soil and the pot will therefore dry out faster and faster the older the plant gets.
Also, all during November and December we get very little sun at our latitude, but this changes rather rapidly in January and February. The plants become thin leaved during dull weather and when they then get a blazing sunny day -all of a sudden- they get fried!