DENJIRO: Today, I made something like this. It's a dried flower.
As you can see, it's quite dry. And this is what I used to dry it: silica gel.
When you put a flower in here, the silica gel absorbs water from the flower, and it dries up in its original shape. Today, we're going to conduct an experiment with silica gel.
Let's make silica gel. This clear liquid is a sodium silicate solution. We'll mix it first.
Now, I'll put hydrochloric acid into the solution.
The solution has become white. When I tilt the beaker...
BOY: It has solidified!
DENJIRO: The chemical change caused the solution to solidify. We'll dry this to get rid of moisture.
Once it gets completely dry, we get silica gel.
Silica gel has many tiny holes like a sponge does, but these holes can't be seen with the naked eye. These holes are where water gets absorbed.
Silica gel is white when it is made, but commercial silica gel has these blue beads, too. This is silica gel that contains cobalt chloride.
When you pour water in here...
BOY: It's turning red!
DENJIRO: Cobalt chloride turns red when it absorbs water. With this chemical, you can easily tell if it’s time to change the silica gel as it has absorbed water.
NARRATOR: Silica gel that has absorbed water and turned red can actually be reused after heating it on a frying pan. Once the water evaporates, the silica gel turns blue. Once, it turns blue, it's ready for use again.
DENJIRO: I hope energy will bring you all happiness. Our magic word is "Happy Energy!”