Hypotonic Solution

The concentration of dissolved substances is lower in the solution outside the cell than inside the cell. The water wants the concentration to be equal. So, the water will rush into the cell to lower the concentration outside the cell. But, there is so much water in the cell, so the cell will burst. Think of it this way. When you make kool-aid, there's sometimes more of the kool-aid mix at the bottom. So, what do you do in that situation? The easy thing to do is to add more water. Then, everything is perfectly mixed. This is a perfect example for a hypotonic solution.