Making Things Move
Forces can do amazing things! They can make things START moving, STOP moving, go FASTER, go SLOWER, or change DIRECTION. Let's explore how forces work!
Learn
A force (a push or pull) can change how something moves. Forces can make things go, stop, speed up, slow down, or turn!
Four Things Forces Can Do
START Moving
A push or pull can make something that's still begin to move!
Example: Pushing a swing to start it moving
STOP Moving
A force can make something that's moving come to a stop!
Example: Catching a ball to stop it
Go FASTER or SLOWER
A force can speed things up or slow them down!
Example: Pushing harder on a bike pedal to go faster
Change DIRECTION
A force can make something turn or go a different way!
Example: Hitting a ball to make it go left
Bigger Force = Bigger Change!
The stronger the push or pull, the more it changes how something moves:
- A gentle push makes a ball roll slowly
- A BIG push makes a ball roll fast and far!
- A gentle tap might not stop a moving wagon
- A BIG push back will stop it quickly!
What Makes Things Slow Down?
Have you noticed that rolling balls eventually stop? That's because of friction!
- Friction is a force that happens when things rub against each other
- Friction slows things down
- Rough surfaces have more friction (things stop faster)
- Smooth surfaces have less friction (things slide more)
Examples
Let's see forces in action!
Example 1: Playing Soccer
The ball is still on the grass.
You kick it (push) - now it's moving! Your push made it START moving.
Your friend kicks it the other way - now it changed DIRECTION!
The ball rolls across the grass and eventually stops - friction slowed it down.
Example 2: Riding a Bike
You're on your bike.
You push on the pedals - you START moving!
You push harder - you go FASTER!
You squeeze the brakes (a push on the wheels) - you SLOW DOWN and STOP!
You turn the handlebars - you change DIRECTION!
Example 3: Pushing a Friend on a Swing
Your friend sits on a still swing.
You push them - the swing STARTS moving!
You push again when they come back - they go HIGHER (faster)!
If you stop pushing, the swing slowly stops because of friction in the chains and air.
Example 4: Rolling Cars on a Ramp
You put a toy car at the top of a ramp.
You let go - gravity PULLS it down, and it STARTS moving!
A car on a steeper ramp goes FASTER (gravity pulls harder).
If you put a pillow at the bottom, the car STOPS (the pillow pushes back).
Example 5: Playing Hockey
A hockey puck slides on ice.
Ice is very smooth - there's less friction!
That's why hockey pucks slide so far and fast!
A puck on carpet would stop much faster because carpet is rough (more friction).
Practice Problems
Think about what force is doing in each situation!
Problem 1
You push a toy car and it starts rolling. What did the force do?
Show Answer
The force made the car START moving!
Problem 2
You catch a ball that was flying toward you. What did your hands do to the ball?
Show Answer
Your hands made the ball STOP moving!
Problem 3
A wagon is rolling slowly. You push it harder. What happens?
Show Answer
The wagon goes FASTER!
Problem 4
A ball is rolling toward you. You tap it to the left. What did you make it do?
Show Answer
You made it change DIRECTION!
Problem 5
You give a ball a tiny push and it rolls a short distance. Then you push it really hard. What's different?
Show Answer
The harder push made the ball go faster and farther! A bigger force makes a bigger change!
Problem 6
A ball rolls on grass and stops. Another ball rolls on a wood floor and goes much farther. Why?
Show Answer
The grass has more friction because it's rough. The smooth floor has less friction, so the ball can roll farther!
Problem 7
Why does a ball always come back down when you throw it up?
Show Answer
Gravity pulls it back down! Gravity is a force that pulls everything toward the ground.
Problem 8
You're riding your bike fast. You squeeze the brakes. What happens?
Show Answer
You slow down and stop! The brakes push against the wheels to make you stop.
Problem 9
Two kids are on a seesaw. One kid pushes off the ground. What happens?
Show Answer
The seesaw starts moving! The push makes the seesaw go up and down.
Problem 10
A hockey puck slides farther on ice than on carpet. Why is ice special?
Show Answer
Ice is very smooth, so there's less friction. Things can slide farther when there's less friction!
Check Your Understanding
Question 1
Name four things that forces can do to moving objects.
Show Answer
Forces can: 1) Start movement, 2) Stop movement, 3) Make things faster or slower, 4) Change direction!
Question 2
What happens if you push something harder?
Show Answer
A bigger push makes a bigger change! Things go faster, farther, or stop more quickly!
Question 3
What is friction?
Show Answer
Friction is a force that happens when things rub together. It slows things down. Rough surfaces have more friction!
Question 4
Why do things fall down when you drop them?
Show Answer
Gravity! Gravity is a force that pulls everything down toward the ground.
Next Steps
Ramp Experiment!
Try this experiment at home:
- Make a ramp with a book or board
- Roll a toy car or ball down the ramp
- Make the ramp steeper - what happens?
- Put different surfaces at the bottom (carpet, towel, smooth floor)
- Which surface lets the car roll the farthest?
- Practice predicting what will happen when you push or pull things
- Notice how forces work in playground games
- Think about friction - why do we wear rubber-soled shoes?
- You've completed the Simple Forces unit! Great job!