Today, Zhou Yiqun, Xu Yang and Yang Xiaoqing and I did an experiment about the ups and downs of science class. Before the experiment, we prepared many experimental supplies, such as a big basin, water, plastic foam, empty toothpaste tube, small medicine bottle, plasticine, sponge, eggs, paper clips, soil, six long nails and two short nails. Our experiment is to put some water in a big basin, then put these objects into the water and observe their ups and downs. However, we have to guess their ups and downs first.

We think that the objects that can float are plastic foam, empty toothpaste tubes and small medicine bottles. The sinking objects are plasticine, sponge, eggs, paper clips, dirt and nails. We put the plastic foam into the water first, and it floated. We put the empty toothpaste tube into the water, but it sank. At this time, the science teacher came in and filled the empty toothpaste tube with air, so it floated. We put plasticine into the water again and it sank. The science teacher asked us to make plasticine into a boat shape, which really floated. We put the vial, sponge, egg, paper clip and nail into the water respectively. As a result, vials and sponges floated, while eggs, paper clips and nails sank. Then, we have to change their ups and downs. We first inserted the nail into the plastic foam to make it sink, but it floated. We added some soil to the bottle and it sank. We tied the paper clip to the sponge again to make it sink, but it floated. Soon, this interesting experiment was over.

Hydraulic/hydraulic pressure

One day I saw the diver coming out of the sea on TV. I saw that he was very tired. I asked my father why. Dad said: it's because of the water pressure. Let's do an experiment! "

The materials my father asked me to find are: 1 2L soda can, 1 roll tape, 1 nail, 1 flat plate.

I put the soda can away, and nailed nails in the holes 2 cm, 4 cm, 8 cm and 10 cm from the bottom of the bottle. Then seal the three holes with adhesive tape, fill the soda can with water, then put the flat plate under the perforated side and tear off the adhesive tape. Do you know what happened? Is there a difference between three-hole water spraying? Of course not. The water 2CM from the bottom is sprayed farthest, followed by the water 4CM from the bottom, and the water closest to the bottom is 10CM.

Dad said, "This proves that the depth of water is different and the pressure of water is different." The deeper the water, the greater the pressure; The shallower the water, the less pressure. Therefore, the hole with a distance of 2CM from the bottom of the bottle shoots farthest and the hole with a distance of 10CM from the bottom of the bottle shoots closest. "

In order to know what other factors are related to stress. I did another small experiment: insert a straw into the mouth of a small paper box and insert it tightly. Then I use a straw to add water to the carton. When the water reached the suction pipe, the bottom of the small carton cracked. After many experiments, the result is the same. It turns out that water pressure is also related to weight. Because the bottom of the carton bears the maximum weight of water, the water pressure is the greatest, so the bottom of the carton cracks.

Water pressure is everywhere, whether it is the water in the tap or the water in the river. If there were no water pressure, we would have no running water to drink now. So water pressure is everywhere!