Energy

Energy

Middle School

​

Learning Objectives

• Define energy and identify its different forms, like kinetic and potential energy.

• Explain the connection between energy, force, and an object’s motion.

• Describe energy transformation and the Law of Conservation of Energy.

• Analyze how mass, speed, and position can affect the energy of an object.

Key Vocabulary

​

Energy

The ability to cause change in an object or a system, and it exists in many different forms.

​

Force

A push or pull that is applied to an object, which can cause a change in its motion.

​

Kinetic Energy

The form of energy that an object possesses by virtue of being in motion.

​

Potential Energy

The stored energy an object has based on its position, condition, or chemical composition.

​

Gravitational Potential

Energy stored in an object as the result of its vertical position or height.

​

Elastic Potential Energy

Energy stored in objects that can be compressed or stretched, such as springs and rubber bands.

Key Vocabulary

​

Energy Transformation

The process of energy changing from one form to another, such as electrical to thermal energy.

​

Law of Conservation

The principle that energy cannot be created or destroyed, only transferred or transformed to other forms.

Energy, Motion, and Force

• Energy is the ability to cause change and comes in many forms.

• Energy is needed for motion, which is a change in an object's position.

• A force, which is a push or pull, requires energy to be applied.

Multiple Choice

What is the fundamental definition of energy?

• The ability to cause change

• A push or a pull on an object

• A change in an object's position

• The weight of a stationary object

Multiple Choice

What is the relationship between energy and motion?

• Energy is required to cause a change in position.

• A change in position creates energy.

• Energy and motion are separate and unrelated concepts.

• Only objects at rest possess energy for motion.

Multiple Choice

Based on the principles of energy and force, what is necessary to make a stationary object start moving?

• Energy must be used to apply a force.

• Motion must happen before a force can be applied.

• A force must be applied without using any energy.

• The object's position must change on its own.

​

​

Kinetic Energy: The Energy of Motion

​

Multiple Choice

What is kinetic energy?

• The energy an object has because it is in motion.

• The energy stored inside an object at rest.

• The energy an object has due to its height.

• The energy produced by a chemical change.

Multiple Choice

If two cars are traveling at the same speed, how does their mass affect their kinetic energy?

• The car with more mass will have more kinetic energy.

• The car with less mass will have more kinetic energy.

• Both cars will have the same kinetic energy.

• Only the speed of the cars determines their kinetic energy.

Multiple Choice

Based on the formula for kinetic energy $$KE = \frac{1}{2}mv^2$$ , what would happen to a car's kinetic energy if its speed were to double?

• The kinetic energy will be doubled.

• The kinetic energy will be quadrupled (four times greater).

• The kinetic energy will be halved.

• The kinetic energy will not change.

Potential Energy: Stored Energy

• Potential energy is stored energy based on an object's position or its shape.

• Gravitational potential energy depends on an object's height above the ground.

• Elastic potential energy is stored when an object's shape is changed.

Multiple Choice

Which statement best defines potential energy?

• Energy that is stored based on an object's position or shape.

• Energy an object has because of its movement.

• Energy that is created by heat.

• Energy an object has because of its temperature.

Multiple Choice

What is the relationship between gravitational and elastic potential energy?

• Gravitational potential energy is based on height, while elastic potential energy is based on an object's shape being changed.

• Gravitational potential energy is a result of changing shape, while elastic potential energy is a result of height.

• Only gravitational potential energy is considered stored energy.

• Only elastic potential energy depends on an object's position.

Multiple Choice

Which of the following objects has both gravitational and elastic potential energy?

• A compressed spring at the top of a bookshelf.

• A car driving on a flat road.

• A ball resting on the floor.

• A stretched rubber band on a table.

​

​

Energy Transformation and Conservation

Energy Transformation

• Energy can be transformed, or changed, from one form of energy to another.

• For example, a toaster transforms electrical energy into thermal energy to toast bread.

• Our bodies convert chemical energy from food into kinetic energy for movement.

Energy Conservation

• This fundamental law states that energy cannot be created or destroyed.

• Energy can only be transferred between objects or transformed from one form to another.

• The total amount of energy within an isolated system always remains constant.

Multiple Choice

What is the fundamental law of energy conservation?

• It cannot be created or destroyed, only change form.

• It is lost whenever it is used to do work.

• It can be created by machines but not by nature.

• The total amount of it in the universe is decreasing.

Multiple Choice

How does the example of a toaster help explain energy transformation?

• It shows how electrical energy changes into thermal energy.

• It demonstrates that energy is destroyed by the toaster.

• It proves that thermal energy can be created from nothing.

• It explains how kinetic energy is converted to electrical energy.

Multiple Choice

A person eats food to get chemical energy and then uses that energy to move. What conclusion can be drawn about the energy in this system?

• The total energy in the system remains constant as it is converted from chemical to kinetic form.

• More kinetic energy is produced than the chemical energy that was stored in the food.

• The chemical energy is destroyed in order to create the kinetic energy for movement.

• The transformation process causes a loss of total energy in the system.

​

Common Misconceptions

Misconception	Correction
Energy is destroyed when things stop moving.	Energy is not destroyed. It changes into other forms, like heat from friction.
An object at rest has no energy.	Objects at rest can have stored potential energy due to their position or state.
Energy and force are the same.	Energy is the ability to cause change. A force is a push or pull.

​

Summary

• Energy is the ability to cause change and is required for all motion.

• Kinetic energy is the energy of motion; potential energy is stored energy.

• Energy can be transformed from one form to another, but is never lost.

• The Law of Conservation of Energy states that energy is never created or destroyed.

Poll

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

• 1

• 2

• 3

• 4