Grade: Grade 3 Subject: Science Unit: Forces & Motion SAT: ProblemSolving+DataAnalysis ACT: Science

Motion and Speed

Everything around us is moving! Cars drive down streets, birds fly through the sky, and even you move when you walk to school. Let's explore what motion and speed are all about!

What is Motion?

Motion is When Something Changes Position!

When an object moves from one place to another, we say it is in motion. If something stays in the same spot, it is at rest (not moving).

📍 Key Vocabulary

Motion - A change in an object's position compared to where it started.

Start Position --> End Position
If these are different, the object is in motion!

🛋️ At Rest vs. In Motion

Look around your room. Which things are moving and which are staying still?

🪑
At Rest
A chair sitting in place - not moving
🐕
In Motion
A dog running across the yard - moving!
Think About It: You need a reference point to tell if something is moving. If you're on a bus, are you moving? Compared to the seat, no! Compared to trees outside, yes!

What is Speed?

Speed Tells Us How Fast Something Moves!

Speed is how quickly an object changes its position. Some things move fast and some things move slow.

Fast vs. Slow

Objects can move at different speeds. Let's compare!

🐢
Slow
Turtle
Takes a long time to go a short distance
🐇
Fast
Rabbit
Goes a long distance in a short time
🚗
Faster
Car
Much quicker than animals walking
✈️
Very Fast
Airplane
Travels many miles in just one hour

Speed Simulator - Watch Different Speeds!

Click a speed button, then click "Go!" to see how fast the car moves.

🚗 🏁
Current Speed: Medium

Distance and Time

Speed = Distance divided by Time

To find speed, we look at how much distance (how far) something travels in a certain amount of time (how long).

Understanding the Speed Formula

Speed = Distance / Time
How far you go divided by how long it takes
Example: A bike travels 10 miles in 1 hour
Speed = 10 miles / 1 hour = 10 miles per hour (mph)

📏 Distance

Distance - How far an object travels. We measure it in feet, meters, miles, or kilometers.

Time

Time - How long it takes for something to happen. We measure it in seconds, minutes, or hours.

🚶
Walking
About 3 miles per hour
🚴
Biking
About 10-15 miles per hour
🚗
Car on Highway
About 60-70 miles per hour
🚄
Fast Train
About 150-200 miles per hour

Race Time! Which One is Fastest?

Click "Start Race" to see who wins! Watch how speed affects who finishes first.

Turtle
🐢
Rabbit
🐇
Cheetah
🐆

Changing Direction

Motion Can Change Direction!

Objects don't always move in a straight line. They can turn, zigzag, curve, or go in circles. When direction changes, the motion changes too!

🧭 Directions of Motion

⬆️
Up
A ball thrown in the air
⬇️
Down
Rain falling from clouds
⬅️
Left
A car turning left
➡️
Right
A car turning right

Direction Controller - Move the Ball!

Use the arrow buttons to move the ball around. Watch how it changes direction!

Click an arrow to move the ball!
Fun Fact: When you ride a merry-go-round, you're always changing direction even though you feel like you're going in circles! That's because "direction" means which way you're pointed at any moment.

Predicting Motion

We Can Guess Where Things Will Go!

By watching how something moves, we can predict (make a good guess about) where it will go next. Scientists use this to understand how the world works!

🔮 Making Predictions

To predict motion, think about:

  • Direction - Which way is it going?
  • Speed - How fast is it moving?
  • Forces - Is anything pushing or pulling it?
A ball rolling down a ramp...
Will keep rolling in the same direction until something stops it!

Prediction Challenge!

Read each situation and predict what will happen!

A ball is rolling to the right on a flat floor. What will it do?
Score: 0 / 0

Practice Problems

Test your knowledge about motion and speed!

Question 1

What do we call it when an object changes its position?

Question 2

Which animal is typically the SLOWEST?

Question 3

To find speed, what do you divide distance by?

Question 4

A car travels 60 miles in 1 hour. What is its speed?

Question 5

When a ball bounces off a wall, what changes?

Check Your Understanding

If a bicycle and a car both start at the same place and travel for 1 hour, which will go farther?

A toy car is sitting on a table. Is it in motion or at rest?

You throw a ball straight up. What happens to its direction?

What We Learned

🏃

Motion

When an object changes its position from one place to another.

Speed

How fast something moves - distance divided by time.

📏

Distance & Time

We measure how far (distance) and how long (time) to find speed.

🔄

Direction

Objects can change which way they're moving - up, down, left, right!

🔮

Prediction

We can guess where things will go by watching their motion.

Great Job! You've learned all about motion and speed! Now you can observe the world around you and understand why things move the way they do. Keep exploring and asking questions about motion!

Next Steps

  • Observe moving objects around you - are they fast or slow?
  • Try timing how long it takes to walk across your classroom
  • Watch a ball roll and predict where it will stop
  • Think about how forces (pushes and pulls) affect motion