Why Does a Coin Appear When You Pour Water Into a Bowl?

What Crafty Clover says in this video

Intro

Hi there, curious minds! I'm Crafty Clover! Let's discover something amazing. Why does a coin appear when you pour water into a bowl?

The Big Idea

A coin in an empty bowl can hide behind the rim. Pour in water, and light from the coin bends as it leaves the water. Now it clears the rim, and your brain thinks the coin floated into sight.

Hidden Coin

Step one: the hidden coin. In an empty bowl, light from the coin travels in a straight line. The rim of the bowl blocks that line, so you cannot see the coin.

Add Water

Step two: add water. Light from the coin bends as it leaves the water and enters the air. The bent path now clears the rim and reaches your eye.

Brain Trick

Step three: the brain trick. Your brain thinks light always travels straight, so it puts the coin higher up. The coin never moved. Only the light's path changed.

A Closer Look

Let's take a closer look! The coin sits at the bottom of the bowl. The rim blocks your view. Water bends the light over the rim. Now the coin pops into view.

Quick Facts

Quick facts! The bending of light at a surface is called refraction. Light bends because it travels slower in water than in air. The same bending makes a fish look closer to the surface than it is. Pour water gently so nothing spills.

Think Like a Scientist

Now, think like a scientist! Place a coin in an empty bowl and step back until the rim just hides it. Keep your head still while a friend pours water in gently. Does the coin pop into view? Wipe up any spills.

Outro

The coin did not move. Bent light made it appear. Science is amazing! Crafty Clover can be found on Amazon Books, Google Bookstore, and Apple Books. Available for purchase or download! Bye for now!