Why Does a Glass of Water Flip an Arrow Upside Down?

What Crafty Clover says in this video

Intro

Hi there, curious minds! I'm Crafty Clover! Let's discover something amazing. Why does a glass of water flip an arrow upside down?

The Big Idea

A tall glass of water is curved like a lens, so it bends the light passing through it. At the right distance, the picture flips from side to side. An arrow pointing left suddenly points right.

Curved Glass

Step one: curved glass. A round glass full of water is thick in the middle and thin at the edges. That shape bends light, just like a lens.

Light Crosses

Step two: light crosses. The light from the left side of the arrow bends toward the right, and the right side bends toward the left. The rays cross over each other inside the glass.

Flipped Arrow

Step three: the flipped arrow. Once the card is far enough behind the glass, your eye sees the crossed rays. So the picture turns around, left for right.

A Closer Look

Let's take a closer look! Draw an arrow on a card. Hold it behind a tall glass of water. Slowly move the card farther away. At some distance, the arrow flips direction.

Quick Facts

Quick facts! Cameras and your own eyes also use lenses. A lens in your eye flips the picture upside down on the back of your eye. Your brain turns it right side up for you. Use a glass you can safely hold, and wipe up spills.

Think Like a Scientist

Now, think like a scientist! Draw an arrow on a card, and hold it behind a tall clear glass of water. Slowly move the card away. At what distance does the arrow flip direction? Hold the glass with both hands.

Outro

A glass of water is a lens that can flip a picture. Science is amazing! Crafty Clover can be found on Amazon Books, Google Bookstore, and Apple Books. Available for purchase or download! Bye for now!