Day 1: The Bedrock of Gravity

1. The Unbreakable Laws of Gravity

Gravity is a force that pulls any two objects with mass toward each other.

• Law 1: The pull gets stronger when the objects are heavier.
  Analogy: Imagine two magnets. The bigger the magnet, the stronger it pulls the other one.
• Law 2: The pull weakens the farther apart the objects are.
  Analogy: Think of a rubber band stretched between two toys. The farther the toys, the looser the band feels.

FIRST PRINCIPLE:
The force of gravity between two masses is proportional to the product of their masses and inversely proportional to the square of the distance between them.

2. Why Gravity Feels Like a Pull

When you stand on the Earth, your body has mass, and the Earth has a huge mass. Because of the first principle, the Earth pulls you down. The same rule works for the Moon pulling the ocean, or the Sun pulling the planets. The only difference is how big the masses are and how far apart they are.

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