Hooked on Science: Reversing arrow

Materials

• Transparent glass
• Black permanent marker
• Piece of paper
• Water

Instructions

• STEP 1: Fill the transparent glass with water.
• STEP 2: Using the black permanent marker, draw a horizontal arrow on the piece of paper.
• STEP 3: Place the piece of paper with the arrow behind the glass filled with water. Make sure the paper is touching the glass and observe the arrow.
• STEP 4: Move the piece of paper with the arrow away from the glass of water and observe the arrow. What are the effects of placing the piece of paper with the arrow behind the glass of water?

Explanation

As you move the piece of paper with the arrow away from the glass of water, the arrow appears to reverse. The light is refracted as it passes through the glass, the water, then through the back of the glass and finally through the air to the paper with the horizontal arrow. This refraction causes the horizontal arrow to appear as if it is reversed.