Interactive
University of Colorado

University of Colorado: Ph Et Interactive Simulations: Gravity and Orbits

For Students 9th - 10th
Move the sun, earth, moon, and space station to see how it affects their gravitational forces and orbital paths. Visualize the sizes and distances between different heavenly bodies, and turn off gravity to see what would happen without it.
Unit Plan
E-learning for Kids

E Learning for Kids: Antarctica Penguins: How Does the Moon Influence the Tide?

For Students 4th - 6th
This lesson explains how the moon affects tides on Earth and about the different types of tides.
Primary
MadSci Network

Mad Scientist: Why High Tide Away From the Moon or Sun?

For Students 9th - 10th
An excellent and thorough answer to the often asked question about high tide "bulges" on the side of Earth facing away from the Moon or Sun.
Unit Plan
Physics Classroom

The Physics Classroom: Cavendish and the Value of G

For Students 9th - 10th
A short description of how Cavendish measured the value of G - the universal gravitation constant and supported Newton's theory. Illustrated.
Interactive
Ambleside Church of England Primary School

Ambleside c.e. Primary School: Your Weight on Other Planets

For Students 3rd - 8th
Students enter their weight here on Earth, and find out how much they would weigh on the moon and other planets.
Unit Plan
OpenStax

Open Stax: Newton's Universal Law of Gravitation

For Students 9th - 10th
In the following interactive students will explain Earth's gravitational force and describe the gravitational effect of the Moon on Earth. They will discuss weightlessness in space and examine the Cavendish experiment.