by Dan Meyer

• 1. Is reality closer to the top video or the bottom?
• 2. Using your finger, show just how long it takes light to get from the Earth to the Moon.

• video — flashlight on

• 3. What information will you need to know to solve the problem?

• file — double number line
• image — the distance to the moon
• image — the speed of light

• video — answer

• 4. If it were bright enough, how long would it take Dan's flashlight to reach Pluto?
• 5. Choose an object in the universe and find out how long it will take the light from Dan's flashlight to reach it.'
• 6. If the light takes a month to reach a certain point in space, where might that point be?
• 7. How far does light travel in ten years? (A: Ten light-years. Introduce a new unit of distance.)