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Lesson

Energy Transfer

A baseball arrives at one speed and leaves the bat much faster. Nothing made new energy. So where did all that extra motion come from?

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Driving Question
How does energy transfer cause objects to speed up, slow down, or change motion?
🔬 Learning Science Focus 🔍 Phenomenon First 🧠 Chunked Content 🖼️ Dual Coding ✅ Retrieval Practice 📊 Cause & Effect

What You'll Be Able to Do

By the end of this lesson, you will be able to:

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I can explain how energy is transferred to or from an object during an interaction.
7.MS-PS3-5
I can describe how a change in kinetic energy shows that energy has been transferred.
7.MS-PS3-5
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I can explain why collisions involve energy transfer between objects.
7.MS-PS3-5
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I can use evidence to support a claim about energy transfer.
7.MS-PS3-5
📚 Instructional Design
Why this section exists
  • State what students will be able to do.
  • Set a clear target before content begins.
Cognitive science
  • Goal setting
  • Advance organizers
Bloom's / DOK
  • Understand to Analyze
  • DOK 1 to 3
Accessibility considerations
  • Plain "I can" statements
  • Standard code shown for reference
  • Short, scannable cards

Words You'll Meet

Choose a card to see what each word means.

📚 Instructional Design
Why this section exists
  • Front-load the terms students will meet.
  • Lower the language barrier before reading.
Cognitive science
  • Pre-teaching vocabulary
  • Reduced extraneous load
Bloom's / DOK
  • Remember to Understand
  • DOK 1
Accessibility considerations
  • One card open at a time
  • Click to reveal, no hover
  • Plain, short definitions

Faster Out Than In

A pitched baseball is already moving fast when it reaches the plate. After it meets the bat, it flies away even faster. The ball did not make that extra speed on its own.

Real World Phenomenon

Where Did the Extra Motion Come From?

Watch a batter make contact. The ball comes in fast, the bat swings to meet it, and in a split second the ball rockets back out at a higher speed than it arrived. The ball did not suddenly create its own energy. Something happened in that collision. So where did the extra motion come from?

Ball arrives Bat swings 💥 Ball leaves faster
The ball leaves the bat faster than it arrived. Its kinetic energy went up during the collision.
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Make a prediction: The ball leaves the bat faster than it arrived. Where did the extra motion come from?
Here's the big idea

The best answer is B. Energy is not created out of nothing, and it does not vanish and return. The swinging bat carries energy of motion, and when it strikes the ball, some of that energy transfers into the ball. The ball's motion increases because energy moved into it. To prove that, we follow the kinetic energy, which is exactly where this lesson goes next.

Where we're headed: First we'll define what energy transfer really means. Then we'll watch energy move during collisions, connect speed changes to kinetic energy, and finish by using evidence to back up claims about where the energy went.
📚 Instructional Design
Why this section exists
  • Anchor the lesson in a real phenomenon: a bat-and-ball collision.
  • Raise a question students will want answered.
Cognitive science
  • Curiosity gap
  • Phenomenon-based learning
Bloom's / DOK
  • Understand
  • DOK 2
Accessibility considerations
  • Concrete, familiar example
  • Short framing text
  • Visual anchor

What Is Energy Transfer?

You already know energy comes in different forms and can change from one form to another. Now we focus on something simpler and more direct: energy moving from one object to another.

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Energy Moves Between Objects

Energy cannot be created or destroyed. But it can move. When one object gives energy to another, the first object ends up with less and the second ends up with more. The total amount of energy stays the same. It has simply changed location.

To see this clearly, scientists pick a system, the set of objects they want to study together. Then they watch the energy move between the parts of that system.

Key idea: Energy Transfer

Energy transfer is the movement of energy from one object to another. When energy transfers, the amount of energy each object has changes. One object gains energy and another loses the same amount.

Key idea: Kinetic Energy

Kinetic energy is the energy an object has because of its motion. The faster an object moves, the more kinetic energy it has. This is the kind of energy we will track all lesson, because changes in motion are easy to see and measure.

Key idea: System

A system is the group of objects you choose to study together. In the opening example, the system is the bat and the ball. Drawing a circle around a system helps you track exactly where energy goes.

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The key pattern: If an object's kinetic energy changes, energy must have transferred to it or from it. A change in motion is a clue that energy moved.
📚 Instructional Design
Why this section exists
  • Define energy transfer before applying it.
  • Distinguish transfer (object to object) from transformation (form to form).
Cognitive science
  • Prior knowledge activation (forms of energy)
  • Building on conservation of energy
Bloom's / DOK
  • Understand
  • DOK 1 to 2
Accessibility considerations
  • Key terms defined in place
  • Short paragraphs
  • One clear pattern stated

Energy on the Move

A collision is one of the clearest places to see energy transfer. Two objects touch, push on each other, and energy moves between them. Click an example to follow the energy.

A B 💥 A slows down, B speeds up
1 · Bat & baseballbat → ball
2 · Foot & soccer ballfoot → ball
3 · Billiard ballscue → eight ball
4 · Bumper carscar → car
Click an example
Pick a collision →
Each example is a system of two objects that touch and push on each other. Click any one to see which object loses kinetic energy and which one gains it.
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The same story every time: In each collision, a force acts during contact and energy moves from the faster object to the slower one. One object speeds up, the other slows down, and energy is transferred between them.
📚 Instructional Design
Why this section exists
  • Show energy transfer across multiple collisions.
  • Build a repeatable pattern students can generalize.
Cognitive science
  • Multiple worked examples
  • Dual coding with the interactive diagram
  • Pattern recognition across cases
Bloom's / DOK
  • Understand to Apply
  • DOK 2
Accessibility considerations
  • Click to reveal each case, no hover
  • Labeled diagram paired with text
  • Parallel, familiar examples

Speeding Up and Slowing Down

Kinetic energy depends on motion, so watching an object's speed tells you what is happening to its energy. A change in speed is the visible sign of a change in kinetic energy.

Speeding Up
Kinetic energy increases
  • A skateboard rolls faster down a ramp
  • Energy was transferred to the object
  • More speed means more kinetic energy
Slowing Down
Kinetic energy decreases
  • A rolling ball slows and stops on grass
  • Energy was transferred away from the object
  • Less speed means less kinetic energy
Read the Motion, Find the Energy

You do not need special tools to detect energy transfer. You can read it from the motion. If an object speeds up, energy was transferred into it. If an object slows down, energy was transferred out of it.

When a rolling ball slows and stops, its kinetic energy did not vanish. It transferred to the ground and the air through friction. The energy moved out of the ball and into its surroundings.

Connect it back: The baseball left the bat faster, so its kinetic energy increased, which means energy was transferred to it. The same rule that explains a slowing ball also explains a speeding one.
📚 Instructional Design
Why this section exists
  • Link the measurable variable (speed) to kinetic energy.
  • Make energy transfer observable, not abstract.
Cognitive science
  • Comparison and contrast (speeding up vs slowing down)
  • Concrete to abstract
Bloom's / DOK
  • Understand to Analyze
  • DOK 2
Accessibility considerations
  • Side-by-side comparison cards
  • Short, parallel bullet lists
  • Plain causal language

Backing Up the Claim

In science, saying that energy transferred is a claim. A claim is only as strong as the evidence behind it. The standard for this lesson asks you to support claims about energy transfer with evidence.

Key idea: Claim and Evidence

A claim is a statement that answers a question, such as "energy was transferred to the ball." Evidence is the observation or measurement that supports it, such as "the ball's speed increased after the bat hit it." A measured change in kinetic energy is strong evidence that energy transferred.

Why Does a Moving Ball Stop?

Claim: Energy transferred out of the ball.

Evidence: The ball was moving, then it slowed and stopped. Its speed dropped to zero, so its kinetic energy decreased. Energy did not disappear. It transferred to the ground and air through friction.

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Why Does a Skateboard Speed Up Downhill?

Claim: Energy transferred into the skateboard.

Evidence: The skateboard rolled faster and faster as it went down. Its speed increased, so its kinetic energy increased. That gain in kinetic energy is evidence that energy was transferred to it.

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The reasoning move: Start with what you observe about motion. If kinetic energy went up, energy transferred in. If it went down, energy transferred out. The change in motion is your evidence.
📚 Instructional Design
Why this section exists
  • Practice the core skill of 7.MS-PS3-5: argue from evidence.
  • Model claim-and-evidence reasoning explicitly.
Cognitive science
  • Worked examples of argumentation
  • Making thinking visible
Bloom's / DOK
  • Analyze to Evaluate
  • DOK 2 to 3
Accessibility considerations
  • Consistent claim-evidence structure
  • Familiar examples
  • Short, labeled paragraphs

Three Collisions, One Pattern

Let's trace cause and effect through three familiar collisions. In each one, a moving object transfers energy to a slower object, and you can see the result in the motion.

Bat → baseball. The fast-moving bat strikes the ball. Energy transfers from the bat to the ball, and the ball speeds up and flies away. Cause: the bat's motion. Effect: the ball gains kinetic energy.
Runner → soccer ball. The runner's foot moves into the still ball. Energy transfers from the foot to the ball, and the ball speeds up. Cause: the foot's motion. Effect: the ball gains kinetic energy.
🎩 Cue ball → eight ball. The moving cue ball hits the still eight ball. Energy transfers between them, so the cue ball slows and the eight ball speeds up. Cause: the cue ball's motion. Effect: the eight ball gains kinetic energy.
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The pattern holds every time: a moving object carries kinetic energy, contact transfers some of that energy to another object, and the second object's motion changes as a result. Different objects, same cause and effect.
📚 Instructional Design
Why this section exists
  • Generalize the model across cases.
  • Make the cause-and-effect chain explicit.
Cognitive science
  • Interleaved examples
  • Cause-and-effect modeling
  • Transfer to new contexts
Bloom's / DOK
  • Apply to Analyze
  • DOK 2
Accessibility considerations
  • Parallel cause-effect labels
  • Familiar sports examples
  • Short, scannable items

Brain Check

Three quick questions before we put it all together. These are not graded. Pulling answers from memory now will help them stick.

Quick Recall · 1 of 3
Just a quick brain check. Not graded.
A still ball is kicked and speeds away. What does the increase in speed tell you?
Quick Recall · 2 of 3
Just a quick brain check. Not graded.
A rolling marble gradually slows and stops on the floor. What happened to its kinetic energy?
Quick Recall · 3 of 3
Just a quick brain check. Not graded.
In the bat-and-ball collision, where does the ball's extra motion come from?
📚 Instructional Design
Why this section exists
  • Strengthen memory through retrieval before the wrap-up.
  • Surface misconceptions early.
Cognitive science
  • Retrieval practice
  • Generation effect
  • Productive struggle
Bloom's / DOK
  • Understand to Apply
  • DOK 1 to 2
Accessibility considerations
  • Ungraded and low stakes
  • Immediate feedback
  • Short tasks reduce load

Following the Energy

You started with a question: where did the baseball's extra motion come from? Now you can trace the whole chain, step by step.

It Starts With Motion
A moving object carries kinetic energy.
The swinging bat is moving, so it has kinetic energy. Any moving object carries energy because of its motion, ready to be passed on.
Contact Transfers Energy
During the collision, energy transfers from one object to the other.
When the bat and ball touch, a force acts between them and energy transfers from the bat into the ball. Energy is not created. It moves between interacting objects.
The Motion Changes
The change in kinetic energy is your evidence.
The ball leaves faster, so its kinetic energy increased. That change is the evidence that energy was transferred to it.
The full chain:
A moving object has kinetic energy Contact applies a force Energy transfers between objects Kinetic energy changes Speed goes up or down
When the kinetic energy of an object changes, energy has been transferred to or from that object. Energy is never created or destroyed in these events. It simply moves between interacting objects, and the change in motion is the proof.
📚 Instructional Design
Why this section exists
  • Tie the pieces into one cause-and-effect chain.
  • Answer the opening question directly.
Cognitive science
  • Schema building
  • Elaboration
  • Coherent narrative
Bloom's / DOK
  • Understand to Analyze
  • DOK 3
Accessibility considerations
  • Step-by-step beats
  • Plain causal language
  • Builds on prior sections

Check Your Understanding

Ten questions covering everything you explored, from kinetic energy to collisions to claims and evidence. Answer every question, then submit.

Your score will not be sent Your score will be sent to your teacher
0 / 10 selected
🧠 Show Your Thinking

Scientists don't just know the answer. They explain their thinking.

Write your own explanation first. Then submit your work to compare your thinking with a model answer.

In one or two sentences, explain how the baseball ends up moving faster after it meets the bat. Trace the energy from the bat to the ball, and explain what the ball's change in speed proves. Use the word transferred.

One strong way to say it The swinging bat is moving, so it carries kinetic energy. When the bat and ball collide, a force acts during contact and some of that energy is transferred from the bat into the ball. The ball speeds up because energy moved into it, and that gain in kinetic energy is the evidence that energy was transferred. No energy was created; it simply moved between the two objects. If your sentences follow the energy from the bat to the ball and use the change in speed as proof, you have it.
📚 Instructional Design
Why this section exists
  • End the lesson with the student building the energy-transfer chain in their own words, not selecting it.
  • Give the one place where the student generates rather than clicks.
Cognitive science
  • Generation effect and self-explanation
  • Cause and effect: tracing energy from bat to ball
  • Self-check reveal for comparison, ungraded
Bloom's / DOK
  • Analyze to Evaluate
  • DOK 3
Accessibility considerations
  • Short response, one or two sentences
  • Keyword scaffold provided
  • Model answer revealed after submitting

🔍 The Question You Came In With You started this lesson asking: "How does energy transfer cause objects to speed up, slow down, or change motion?" If you can connect a change in kinetic energy to energy moving into or out of an object, you have answered it.
📚 Instructional Design
Why this section exists
  • Check understanding against the lesson goals.
  • Give students and teachers a clear signal.
Cognitive science
  • Retrieval practice
  • Feedback loops
Bloom's / DOK
  • Understand to Apply
  • DOK 1 to 2
Accessibility considerations
  • Answer explanations provided
  • Practice and classroom modes
  • Plausible, evenly placed options

More Learning

The lesson is just the beginning. Dig deeper into how kinetic energy moves between objects during collisions, and how a change in motion becomes evidence of energy transfer. More investigations, simulations, and challenges are coming soon.

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More Coming Soon
The lesson is just the beginning. More investigations, simulations, and challenges are coming soon.
Coming Soon
📚 Instructional Design
Why this section exists
  • Offer pathways beyond the core lesson.
  • Signal that learning continues past the quiz.
Cognitive science
  • Interest-driven extension
  • Transfer to new contexts
Bloom's / DOK
  • Apply to Analyze
  • DOK 2 to 3
Accessibility considerations
  • Optional and self-paced
  • Clear labels for what is available
  • No penalty for skipping