Rocket is still thinking about the paper race. "So if there were no air, the flat sheet would not be slowed?" he asks.
"We cannot remove all the air from the workshop," Raven says. "But astronauts once tested it somewhere with almost no air."
Nova projects a gray, dusty landscape. "The Moon," she says softly.
An astronaut in a white suit holds out a hammer and a feather. Rocket leans so close his glasses nearly touch the hologram.
"Okay," he says. "My prediction is ready."
Astronauts on the Apollo 15 mission walked on the Moon. At the end of their last moonwalk, Commander David Scott did a famous test.
He held a heavy hammer in one hand and a light falcon feather in the other. He dropped them at the same time.
The Moon has almost no air, so there was no air resistance.
The hammer and the feather hit the ground at the same moment.
Without air, objects released together fall at the same rate, no matter how heavy they are.
On Earth, air slows light, flat things like feathers and paper sheets.
| Statement | True or false? |
|---|---|
| Heavy objects always fall faster, even with no air. | ? |
| The Moon's gravity pulled the hammer and feather toward its center. | ? |
On Earth, a feather drifts down slowly. Air pushes on it.
On the Moon, there is almost no air to push.
So the heavy hammer and the light feather fell together.
| Statement | True or false? |
|---|---|
| The hammer-feather drop happened on the Apollo 15 mission. | ? |
| The feather fell much more slowly on the Moon. | ? |
| The Moon has almost no air. | ? |
| Without air, heavy and light objects fall at the same rate. | ? |
You connected your paper test to a real Moon experiment. Tomorrow we will find gravity at work all around us.