1. Direct Measurement:
* Lunar Lander Data: The Apollo missions, especially the lunar landers, directly measured the gravitational acceleration on the Moon's surface. The data confirmed that the gravitational pull on the Moon is about 1/6th that of Earth.
2. Observation of Objects in Free Fall:
* Astronauts' Movements: We have seen footage of astronauts bounding across the lunar surface with ease. Their movements clearly demonstrate the weaker gravitational pull.
* Lunar Roving Vehicle (LRV): The LRV, used for exploring the Moon's surface, also behaved differently under the lower gravity.
3. Orbital Mechanics:
* Lunar Orbit: The Moon orbits Earth at a specific distance and speed. This orbital motion is dictated by Earth's gravity and the Moon's own mass and gravity. The observed orbit of the Moon confirms the lower gravity on its surface.
4. Scientific Explanation:
* Mass and Gravity: The force of gravity is directly related to an object's mass. The Moon has significantly less mass than Earth, resulting in a weaker gravitational pull.
Therefore, it's not a single experiment but a collection of observations, measurements, and scientific understanding that collectively prove the lower gravity on the Moon.