. Potatoes are made up of 99% water and 1% "potato matter." Jack bought 100 pounds of potatoes and left them outside in the sun for a while. When he returned, he discovered that the potatoes had dehydrated and were now only made up of 98% water. How?

It could have been evaporation in the water cycle. What happens is that in liquid water, the atoms and molecules are moving easily. In a solid, they are squeezed together and are packed tightly. In gas, they are moving frantically about.

So, when the potato contained water of 99%, the atoms were moving freely, but when you left it in the sun, the atoms and molecules began to start gaining speed until the atoms were so fast that they escaped into the air. That is why only 98% of the water was left.