Does Light Travel in a Straight Line?

 Learning Concepts

1. Light travels in a straight line.
2. When something blocks the path of light a shadow is formed.

Materials 

• flashlight
• 3 index cards with a hole punched in the center of each card
• something to hold the 3 cards upright (I used 3 clips) 
 

Directions

• Stand the cards up a few inches apart on a flat surface. (Line up the holes.)
• Shine a flashlight from one end through all the holes.
• Did the light travel through all the holes?
• Move the middle card a little so the hole is not lined up.
• Shine a light through the holes.
• What happened?
• Did the light travel through all the holes? 
• Does light travel in a straight line?
• What happens to light when it is blocked?
• How is a shadow formed?