DENJIRO: Take a look at this knife. It’s a handmade bronze knife. It is said that around 3,000 B.C., the Bronze Age began in Mesopotamia and Egypt. So what exactly is bronze? Bronze is made by adding a bit of melted tin to copper. Copper can be rather easily obtained from chalcopyrite, and tin from cassiterite.
Now, let’s actually make a bronze knife. If the mixture contains a lot of tin, it will get hard but brittle. If there’s less tin, it’ll be soft and malleable, so you need to adjust the ratio according to what you are making. In order to make a hard knife that won’t break easily, the ratio of tin to copper will be 1:9. I’m going to add copper and tin pellets in a crucible and melt them. I’ve heated the two materials to about 1,000 degrees Celsius, and they’ve become a liquid. I’m now going to pour the liquid into a sand casting mold that’s in the shape of a knife. Once it cools down and hardens, I take it out of the mold.
BOY: It’s in the shape of a knife.
DENJIRO: Now I just have to polish this, and my bronze knife will be complete. Let’s try using it. I’m going to split this piece of wood.
BOY: That’s a sturdy knife!
DENJIRO: Now I’m going to shave some wood.
BOY: It cuts well too!
DENJIRO: You may think that bronze isn’t as practical as iron, but as you can see, it can make a useful tool. Bronze is still widely used today, in things like statues and medals.
I hope energy will bring you all happiness. Our magic word is "Happy Energy!”
21 окт 2024
