Enchanted Learning
Enchanted Learning: Earth's Oceans Tides
This site explains what tides are and the difference between Proxigean Spring Tides, spring tides, and neap tides, and how these are formed. Graphic illustrations are provided.
Texas Education Agency
Texas Gateway: Newton's Universal Law of Gravitation
By the end of this section, you will be able to explain Earth's gravitational force, describe the gravitational effect of the Moon on Earth, discuss weightlessness in space, and understand the Cavendish experiment.
OpenStax
Open Stax: Newton's Universal Law of Gravitation
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.