有冇d有趣的科學實驗?

I did this when I was in secondary school, it takes less than 1 hour to prepare but days to see the result.

It is a experiment to demonstrate crystal growing, the chemical we used is soldium chloride, i.e. the salt you usually use in kitchen. As you know, crystal will grow in saturation solution. So, the first step is to prepare a saturated solution and the solution must be saturated, otherwise the 'seed' will dissolve in it. It takes long time to prepare and you can fasten the process by warming the solution. After it cools down, you hang a relatively larger sodium chloride crystal in the saturated solution by using a tiny string, and the other end of the string can be tied on a stick hanging on the beaker. You will find the crystal grows after several days.