Day 15 - Under Water Science

Today is a science experiment. Have you ever heard of a scuba diver? Do you know how they work? In order for people to descend under water for more than a few minutes, they need to bring oxygen with them. To do this, there's some science involved. The first piece of equipment to make waves was the diving bell (source: History of Scuba Diving). This was a device that works in the same way that your experiment will.

Here's what you need:


  • A bowl of water
  • A drinking cup or mug
  • A napkin
Here's what to do:

  1. Place the napkin inside the mug or drinking cup. Make sure it is squished to the bottom of the cup.
  2. Turn the glass upside down and make sure the napkin does not fall out.
  3. Place the upside-down glass into the water. Make sure it is completely upside down and not titled at all. There should not be any bubbles when you put it in the water.
  4. Push it to the bottom of the bowl of water.
  5. Pull it out of the water, still keeping it upside down.
  6. Look at the napkin. It should be dry!
Why does this work? When air is trapped inside something, it creates pressure. The pressure of the air in the glass will not allow water to come in. However, if you tip the glass over while it's under water, the air will escape as a bubble, and float to the surface.

Today's challenge was inspired by Funology - a kid-friendly website.

Today's Fun Fact: Orca whales are the same as Killer wales, we just have two names for them. (Source: Kids Can Travel).

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