350-word composition for the sixth grade of primary school: scientific experiment (1)-floating needle on the water

Composition topic: scientific experiment (1)-a needle floating on the water

Keywords: sixth grade, Fushuimian Primary School

This article applies to: the sixth grade of primary school.

Composition source:

This 350-word composition is about the sixth grade of primary school. The topic is: small scientific experiment (1)-a needle floating on the water. Everyone is welcome to contribute enthusiastically.

Small practical experience in science

A needle floating on the water.

He' nan province lingbao city No.1 primary school

Class 4 (3) Zhao

Students, do you know that needles can float on the water? How can a needle float on the water? This is what I thought before, but last night, after I did an experiment with my parents, I found that the needle could actually float on the water.

Very few materials are needed, just a bowl of water, needles and detergent.

Operation method:

1, fill the bowl with water;

2. Carefully place a needle on the water;

3. The needle can float on the water;

Finally, drop a drop of detergent into the water and the needle will sink.

According to the above operation method, I first fill the bowl with clear water and carefully put the needle on the water. The needle really floats on the water. But because my mother didn't record it in time, when I touched the needle floating in the water, it suddenly fell to the bottom of the bowl. Hey! For the first time, the moment from success to failure.

The second time, I quietly put the needle in the water, yeah! The needle is floating on the water again, which makes me very happy. My mother encouraged me to keep putting the needle on the water, and the second needle floated on the water, and I showed a bright smile. Then I put the third needle, but it fell off. In this way, I kept experimenting repeatedly, and the final result was floating on it.

Four needles, sink these four needles below. In this experiment, there are as many floating needles as there are submerged needles, which is a draw.

I think this experiment is very interesting and I want to continue doing it. Mother said, "You can't use so many needles in this experiment. I can only give you three injections. " I promised my mother's request because I had mastered the skill of sticking needles on the water. This time there are two needles on the water and 1 needle under the water, which shows that my experiment has made progress every time.

Finally, I dropped a drop of detergent into the bowl, and instantly, two needles floating on the water fell into the water.

Oh ... yeah! I made it!

Do you know why the needle floats on the water and sinks? Let me tell you something! Because the surface tension of water supports the needle, the needle will not sink. The reason why the needle sinks immediately after the detergent is dropped into the water is that the detergent reduces the surface tension and the needle cannot float.

New term: Surface tension is a cohesive connection formed by water molecules. This cohesive connection is due to the fact that some molecules are attracted together and the molecules squeeze each other to form films. This kind of film is called surface tension, which can hold the object that should sink.

Experimental tip: Needles are dangerous, please ask parents for help.

The experiment last night was so interesting that I learned why the needle can float on the water and the new term "surface tension". In experiments again and again, I learned not to rush for success, but to take your time and find the trick to solve the problem, so that I can win every time. This little scientific experiment made me understand this adage better: there is no royal road to science, and only those who climb along steep mountain roads can hope to reach the peak of glory. Hehe ... I will do such a small scientific experiment in the future.