Energy Change and Conservation

Energy Change and Conservation

Middle School

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Learning Objectives

• Describe how energy can change from one form into another.

• Explain the law of conservation of energy in a closed system.

• Apply energy transformation and conservation concepts to real-world examples.

• Differentiate between single and multiple steps of energy transformations.

Key Vocabulary

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Energy Transformation

The process of energy changing from one form to another, like a toaster making heat.

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Single Transformation

This occurs when energy changes its form only once, such as in a household toaster.

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Multiple Transformations

A series of energy changes, like digesting food for movement and maintaining your body temperature.

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Energy Conservation Law

This law states energy cannot be created or destroyed, only transferred or changed into different forms.

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Kinetic Energy

The form of energy that an object possesses due to its motion, like a rolling ball.

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Thermal Energy

The energy that comes from heat, generated by the movement of tiny particles within an object.

Key Vocabulary

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Chemical Energy

Energy stored in the bonds of chemical compounds and released during a chemical reaction.

Energy Can Change Form

• Energy can be transformed from one form to another.

• A toaster changes electrical energy directly into thermal energy.

• Eating toast involves multiple transformations, like chemical to kinetic energy.

Multiple Choice

Which statement best describes the process of energy transformation?

• Energy changing from one form to another.

• Energy being created from nothing.

• Energy being completely destroyed.

• Energy staying in the same form forever.

Multiple Choice

What principal energy change happens in a toaster?

• Chemical energy is changed into light energy.

• Kinetic energy is changed into electrical energy.

• Electrical energy is changed into thermal energy.

• Thermal energy is changed into chemical energy.

Multiple Choice

When a person eats toast to fuel their body for movement, what energy transformation is taking place?

• Kinetic energy is converted to electrical energy.

• Chemical energy is converted to kinetic energy.

• Thermal energy is converted to chemical energy.

• Electrical energy is converted to thermal energy.

The Law of Conservation of Energy

• Energy is constant; it cannot be created or destroyed, only transferred or transformed.

• A baseball's kinetic energy transfers to the air, becoming thermal energy from friction.

• A baseball travels farther in thin air because less energy becomes heat.

Multiple Choice

Which statement best describes the Law of Conservation of Energy?

• Energy cannot be created or destroyed, only transferred or transformed.

• Energy is created whenever an object starts moving.

• Energy is destroyed by forces like friction.

• Energy can only exist in one form at a time.

Multiple Choice

When a moving baseball slows down due to air friction, what happens to its kinetic energy?

• It is transformed into thermal energy.

• It is destroyed by the air friction.

• It is increased by the air friction.

• It is converted into potential energy.

Multiple Choice

Based on the principle of energy conservation, why does a baseball travel a shorter distance through very dense air?

• The ball's mass increases, making it fly shorter.

• More of the ball's kinetic energy is transformed into heat.

• The force of gravity is stronger in denser air.

• The ball's kinetic energy is destroyed more quickly.

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Common Misconceptions

Misconception	Correction
Energy can be 'used up' or 'lost' forever.	Energy is never destroyed; it is transformed into other forms or transferred.
An object that is not moving has no energy.	Stationary objects can have potential or chemical energy.
Energy transformation is not a common process.	Energy transformations happen constantly all around us.

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Summary

• Energy can be transformed from one form to another in single or multiple steps.

• The law of conservation of energy states that energy is never created or destroyed.

• Seemingly 'lost' energy is often transformed into other forms, like thermal energy from friction.

• Energy transformation and conservation are seen in everyday examples like eating or a flying baseball.

Poll

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

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• 3

• 4