# Lesson Plan: Gravity Science

This lesson plan includes the objectives, prerequisites, and exclusions of the lesson teaching students how to describe the effects of gravity on objects that have mass and how gravity allows planets to orbit stars.

#### Objectives

Students will be able to

- recall that some forces can act between objects without the objects being in contact,
- recall that gravity acts between all objects that have mass,
- recall that the force of gravity between two objects depends on the masses of the objects and the distance between them,
- recall that the force of gravity between two objects increases if their masses are greater and decreases if the distance between them increases,
- recall that gravity acts between the Sun and the planets,
- recall that gravity is the force that causes planets to orbit stars and moons to orbit planets,
- recall that wherever an object experiences the force of gravity of a planet, it is said to be in that planet’s gravitational field.

#### Prerequisites

Students should already be familiar with

- what a force is,
- the idea that gravity is a force,
- the difference between mass and weight,
- the idea that mass can be measured in grams and kilograms,
- the idea that planets orbit stars,
- the idea that moons orbit planets.

#### Exclusions

Students will not cover

- calculations of the gravitational force between two objects using Newton’s law of gravitation,
- calculations of an object’s weight on Earth using ,
- calculations of orbital properties such as orbital speed or period,
- centripetal force,
- noncircular orbits,
- drawing field lines,
- interpreting or recognizing diagrams of the gravitational field,
- calculations of the gravitational field,
- any non-Newtonian ideas about gravity.