CULTIVATE THE BACTERIA THAT GROW ON YOUR HAND
Ingredients: small airtight container, gelatin dessert
If you buy gelatin from a package, follow the instructions to make it. If you do not find gelatin to make, it should be even easier and just touch the gelatin from the glass jar and wait to see what happens.
Heat water on the stove and add the package contents to it, stirring the mixture vigorously until the gelatin grains dissolve. While the solution is still hot, pour into container where you want to cultivate your bacteria, and put the lid on in order to avoid contamination. Store the container in the fridge overnight so the gelatin can solidify. Remove from fridge once solid, touch the gelatin, put the lid on again and leave the container at room temp or near the radiator for a few days.
After some days you will see some white spots on the gelatin. These are your hands’ skin bacteria. Even if you try to wash your hands and repeat the experiment again, we will always have bacteria on our hands.
Explanation
Microorganisms are everywhere but we do not normally see them since they are so tiny and dispersed. In this case, they use the gelatin as food, and since there are so many nutrients in it they can divide (reproduce) many times and accumulate in the container until we are actually able to see them