Potential Energy

Potential Energy

Middle School

​

Learning Objectives

• Define potential energy and differentiate it from kinetic energy.

• Identify and describe different types of potential energy, including gravitational, chemical, and elastic.

• Explain the law of conservation of energy using real-world examples.

• Analyze how potential energy is transformed into other forms of energy in various systems.

Key Vocabulary

​

Potential Energy

The energy stored in an object because of its position or its particular arrangement or state.

​

Kinetic Energy

The energy an object has because of its motion; you can see it as movement.

​

Gravitational PE

Gravitational Potential Energy is related to an object's height, like a rock placed high up.

​

Chemical PE

Chemical Potential Energy is stored in the bonds of substances, like in food or batteries.

​

Elastic PE

Elastic Potential Energy is stored when an object is stretched or compressed, like a drawn bowstring.

​

Conservation of Energy

The rule that energy cannot be created or destroyed, but it can change its form.

Key Vocabulary

​

Joule

The standard unit used to measure both energy and work in science and engineering fields.

​

​

Potential vs. Kinetic Energy

Potential Energy

• This is stored energy an object has because of its position or state.

• A hammer held still above a nail possesses maximum potential energy.

• Energy is measured in a standard unit called Joules, abbreviated as (J).

Kinetic Energy

• This is the energy an object has when it is actively in motion.

• As the hammer swings down, potential energy converts into kinetic energy.

• Energy is never lost, it just transforms from one form to another.

Multiple Choice

What is potential energy?

• The energy an object has because of its motion.

• The energy an object has because of its position or state.

• The energy created when an object is actively moving.

• The standard unit used to measure all forms of energy.

Multiple Choice

What happens to the energy of a hammer as it swings down toward a nail?

• Its potential energy increases as it gets closer to the nail.

• Its potential energy is converted into kinetic energy.

• The total energy is lost as the hammer moves downwards.

• New energy is created from the motion of the hammer.

Multiple Choice

A hammer held still above a nail has 20 Joules of potential energy. Based on the principle of energy transformation, what can be concluded about the amount of energy just before the hammer strikes the nail?

• The total energy is 20 Joules, which has been transformed from potential to kinetic energy.

• The total energy is now greater than 20 Joules because motion adds energy.

• The total energy is less than 20 Joules because energy was lost during the swing.

• The total energy is 0 Joules because the potential energy was used up.

​

​

Types of Potential Energy

Gravitational & Chemical

• Energy is stored in an object based on its height and mass within a gravitational field.

• A heavier object positioned higher up has greater gravitational potential energy.

• Energy stored in the bonds between atoms, such as in food or batteries, is chemical potential energy.

Elastic & Other Forms

• This energy is stored when an object like a rubber band or spring is stretched or compressed.

• A drawn bowstring is a prime example of an object storing elastic potential energy.

• Objects can also have potential energy from being within a magnetic or electrostatic field.

Multiple Choice

What type of energy is stored in the bonds between atoms, such as in food or batteries?

• Chemical potential energy

• Gravitational potential energy

• Elastic potential energy

• Magnetic potential energy

Multiple Choice

Based on the principles of gravitational potential energy, which of the following objects would have the greatest amount?

• A heavy book on a high shelf

• A light book on a high shelf

• A heavy book on a low shelf

• A light book on a low shelf

Multiple Choice

A drawn bowstring, a compressed spring, and an object in a magnetic field are all described as having potential energy. What fundamental principle do these examples share?

• They all have energy stored due to their position or condition.

• They all involve the force of gravity.

• They all store energy in chemical bonds.

• They all must be in motion to have energy.

Energy Transformations in Action

• Potential energy at the top converts to kinetic energy at the bottom.

• Chemical energy in fuel or food is converted into kinetic energy for movement.

• A dam converts water's potential energy into kinetic and then electrical energy.

Multiple Choice

What does it mean for energy to be transformed?

• It is created from nothing.

• It is completely destroyed.

• It stays in the same form forever.

• It changes from one form to another.

Multiple Choice

What is a common relationship shown in the examples of a falling object and the use of fuel?

• Energy for movement is produced from a stored form of energy.

• Kinetic energy is converted into chemical energy for storage.

• Electrical energy is required to create potential energy.

• Kinetic energy is always converted directly into electrical energy.

Multiple Choice

Which statement best explains the sequence of energy transformations that occur at a dam to generate electricity?

• Potential energy becomes kinetic energy, which then becomes electrical energy.

• Electrical energy becomes kinetic energy, which then becomes potential energy.

• Kinetic energy becomes potential energy, which then becomes electrical energy.

• Potential energy is converted directly into electrical energy.

​

Common Misconceptions about Energy

Misconception	Correction
Energy gets 'used up' or destroyed.	Energy is only transformed; the total amount is always conserved.
An object that is not moving has no energy.	Objects at rest can have stored potential energy due to their position.
Potential and kinetic energy are the same thing.	Potential energy is stored, while kinetic energy is the energy of motion.

​

Summary

• Energy is classified as potential (stored) or kinetic (motion).

• Energy transforms between forms but is never created or destroyed.

• Gravitational potential energy depends on an object's mass and height.

• Chemical potential energy is stored in food, fuel, and batteries.

• Elastic potential energy is stored in stretched or compressed objects.

• Energy transformations power everything from pendulums to hydroelectric dams.

Poll

On a scale of 1-4, how confident are you about the concepts covered in today's review?

• 1

• 2

• 3

• 4