How Fast Things Fall and Why Light Bends: teacher key

Gravity, grade 6 edition, written for 6th grade. From a dropped ball to a bent beam of starlight, see how scientists measure what gravity does.

Read the book. Print this page for the key.

Questions and answers

About how fast does a falling object speed up near Earth's surface?
- About 9.8 meters per second every second (answer)
- About 1 meter per hour
- About 100 miles per second
What stays the same on Earth, on the Moon and in orbit?
- Your weight
- Your mass (answer)
- Your height
Why do astronauts on the space station float?
- Space has no gravity
- They and the station are all falling together around Earth (answer)
- The station is very high up
What is gravitational lensing?
- Massive things bending light from more distant things (answer)
- The Moon pulling the sea
- A ripple in space
When did scientists first directly detect gravitational waves?
- 1687
- 1919
- 2015 (answer)