Science Education Standards:

Physical Science:

• As a result of their activities in grades 5-8, all students should develop an understanding of Motions and Forces
• If more than one force acts on an objects along a straight lines, then the forces will reinforce and cancel one another, depending on their direction and magnitude. Unbalanced forces will cause changes in the speed or direction of an object's motion.

Earth and Space Science:

Earth in the Solar System

• Most objects in the solar system are in regular and predictable motion.
• Gravity is the force that keeps planets in orbit around the sun and governs the rest of the motion in the solar system.

Short Description: Students view Web movies of astronauts on the Moon and discuss what they can learn about one's lunar weight; a calculator is provided to get their weight on other planets; a discussion of the causes of weight and gravity is then suggested with different hypotheses.