Light travels in straight lines
A road has a bend. You hear a scooter before you see it. Why?
Step 1 of 4
- A lamp, three cards with holes, and an eye stand in a row.
- Draw a straight line from the lamp to the eye.
- Light goes straight through and reaches the eye.
- Move one hole off the line, and light stops there.
In air, light goes straight, so a bend hides the scooter. Sound still reaches you.
The new word
- Ray — the straight path light takes. Draw a ray as a line with an arrow.
The rule
In air, light goes in a straight line. A wall in the way stops it. Light does not curve to follow a bent pipe.
So a bent pipe hides a flame at the far end. A straight pipe shows the flame.
Watch out!
Your eyes do not send out anything to see. Light from the lamp arrives at your eye.
Now try it. Slide the middle hole. Can the eye see the lamp?
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