by Dan Meyer

• 1. How deep is the chasm?
• 2. Guess as close as you can.
• 3. Give an answer you know is too high.
• 4. Give an answer you know is too low.

• video — Brendan Fraser drops a glowstick into the chasm

• video — Brendan Fraser reveals his calculation of the depth

• 5. If you drop a rock off the top of the Golden Gate Bridge, how long will it take you to hear a splash?
• 6. Falling Rocks.