Because some objects sank in the little bowl of water and in the bathtub full of water. Some objects float in the little bowl of water and in the bathtub full of water. From my experiment, I determined that my hypothesis was correct. Each time I added 10 coils to the nail, it made the electromagnet stronger. Dirty water can get cleaned up a little bit by small rocks and tree seeds and it can be cleaned a lot by sawdust and paper towel.
Nature has all parts in it, in the ground to clean up dirty water.
I learned that if you find any metal around the house and connect it to wire and a light bulb it conducts electricity. I learned when the switch isn't touching it, the bulb won't light up because electricity has to go all the way around the circuit without stopping. I learned that lemon juice has a special chemical in it that burns before paper does. Crystals grow into different shapes.