Today, I did a very interesting scientific experiment at home.
I want to do a buoyancy experiment. I prepare the materials first: a cup, a lot of salt, a spoon and an egg. I started the experiment. I picked up the cup, then filled it with 600 ml of water, and then put the eggs in the water. Now the egg is still at the bottom of the cup. I put three spoonfuls of salt in a row, and the eggs are a little floating. I hope this experiment will succeed. I put another spoonful, and the eggs are still in that position. I put another spoonful, and the egg floated to it, but it didn't show the water. When I put it in the eighth spoon,
The egg finally emerged from the surface of his face, revealing about 1 cm. It is estimated that the water is salty enough at this time. I was still not satisfied, so I poured all the salt in at once. It is estimated that 12.5 spoonfuls of salt should be put now. Wow, the egg rose to 1.5 cm, and now all the 2.5 cm areas are exposed. I want to hatch the eggs in half, but I have used up all the salt.
Why do eggs float? I checked the computer, because salt increases the buoyancy of water, so the proportion of water exceeds the proportion of eggs, so the eggs will not sink to the bottom of the cup, but will always float on the water without sinking.
The Dead Sea is the same principle. The Dead Sea is located in Israel. Because the area where the Dead Sea is located is hot and dry, with high temperature and strong evaporation, salt remains after water evaporation. Over the years, more and more salt has accumulated in lakes, and the Dead Sea has become the saltiest lake in the world, with a salt content as high as 230%-250%. The Dead Sea allows people who can't swim to swim on the sea. People can lie on their backs and float on the sea with pictorial in their hands.
Eggs are floating. Magic science makes things impossible, and the power of science is too great!
June 2008 10
Model essay on science and technology-"making shadows"
Today, I did an experiment to make shadows.
Speaking of shadows, you will say, "How are shadows formed and how do you do it?" If you don't know, let me tell you!
I draw the outline of a little alien first, then cut it out, then stick a straw as a handle behind the outline of the little alien, then turn off the lamp, turn on the desk lamp or flashlight and shine it on the wall, and then put the paper doll between the lamp and the wall, and you can see the little alien on the wall.
When I did this experiment, I understood that the paper puppet blocked the light, cast the shadow of a small alien on the white cloth, and the white cloth let the light pass, so the audience could see the shadow of the paper puppet. The shadow is the same shape as the paper doll. The closer the paper doll is to the lamp, the bigger the shadow.
This is the way I make shadows.