理科関係のブログのリンク集にもなっています。 Let’s make a battery with familiar stuff!
I am Hideyuki Miura. I come from Iwate Prefecture in Japan. Iwate is in the Tohoku region and is located near a latitude of 40 degrees north. It is very cold now, and we have much snow. This is the symbol of Iwate, Mt. Iwate-san. Winter sports such as skiing are also popular in Iwate. Chuson-ji Temple in the historic site Hiraizumi will be designated a World Heritage site. This is a Konjiki-dou in Chuson-ji Temple. The temple is entirely covered with gold. I hope all of you have an opportunity to visit this historic site that is rich in beauty and nature.
I am an elementary school teacher. I will introduce an experiment to help primary schoolchildren understand the structure of a battery.
In Japan, students study the structure of batteries for the first time in a junior high school. Children are familiar with batteries but seldom understand the battery structure. I think that it is very important to know the battery structure because children gain awareness of energy problems by understanding the battery structure. Therefore, I think they need to learn about the battery structure even in elementary school.
I will now introduce an experiment that was conducted for children in the Young Astronauts Club in Japan. It is an experiment in which the children make a battery from familiar stuff.
As everyone knows, Galvani discovered the principle of the battery when he observed that frog legs connected to two different metals contracted; he subsequently developed a portable electroscope. Galvani thought that the muscle of the legs generated electricity. Volta, however, thought that two kinds of metal caused the electricity. This led to the voltaic cell, which was the model of today’s battery.
I usually talk about the history of the voltaic cell, and then show children this experiment.
First, we put a copper strip and a zinc plate in a beaker of water. We then connect an ammeter and a melody I.C. to the two metallic electrodes. You will see that a very small electric current flows even in water. Volta succeeded in making a battery from two different metals and an electrolyte. It is said that Volta used sulfuric acid as an electrolyte, but I use citric acid today. Please add citric acid to the water little by little.
Please make a circuit like this photograph. And please switch to this scale of the ammeter.
Zinc is ionized and starts to melt because of the citric acid. The electrons begin to move, and an electric current flows. This shows that any electrolyte will cause electric current to flow, not just sulfuric acid.
Therefore I introduce the idea that even fruits and vegetables can become batteries. Making a battery is a popular experiment. Let’s start with a lemon battery, and then let’s try many other fruits and vegetables.
Honestly, this is my first time to visit the US, and I didn’t know what fruits and vegetables were available. I’m not sure if it works with these stuff, but let’s try.
The thing which I prepared is ,○○,★★,△△. Please insert a copper sheet and a zinc plate in the vegetables and fruits, and please check whether an electric current is generated.
I tested it, and it took about 5 minutes.
Are you finished? What vegetables or fruits caused stronger currents? As a result of the experiment, I think that you understood acidic materials tend to cause electricity. This experiment helps children understand what materials can generate electric currents.
Finally, let’s make a battery using coins. Here I have some Japanese coins, a 10-yen coin made of copper and a one-yen coin made of the aluminum. I put these coins alternately between a filter paper. I will use salt solution as an electrolyte. A battery can be also made like this. I call it a 55-yen battery. Let’s make it together and check whether electric current flows.
At first please connect a holder to the circuit. And next, put a 10 yen coin in the holder. Then, put a sheet of paper with salt solution on the coin, and finally, put a 1 yen coin on the paper. Please put the 10-yen coin, the paper, and the 1-yen coin alternately five times.
Please make them like this illustration.
Even familiar things can be used to make a battery with large electric currents as we demonstrated today, providing children a new viewpoint.
For example, a battery system is essential for a spacecraft now, and children will be interested in the space development through this experiment.
Furthermore, I hope that more children become interested in the energy problem through such experiments as we conducted.
Finally, I have a small gift for you: Japanese coins, two 10-yen coins and two one-yen coins. Please try to make a 22-yen battery.
I hope that this experiment is useful for you, and you will try it in your class. Thank you very much for your kind attention.
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