Forces and Motion

Day 1

Vocabulary: Write one word on separate pages in your science journal.

•force•motion•push•pull•balanced force

•unbalanced force•gravity•friction

Forces • A force is a push or a pull. You push on a door. You pull on a

wagon. Each push or pull is a force. There are many different forces. The force of the wind pushes sailboats and windmills. Forces in car engines can pull cars down the street.• The amount of force you have to use to move an object depends

on its mass. The more mass something has, the more force you have to use to make it move.

This boy is pushing the These dogs are

snowball. The push of pulling on the

the boy is a force to rope. Each pull

move an object away is a force to move an object toward you.

from you.

Harcourt Science

Day 2

Motion• Birds fly across the sky. Insects crawl across the ground.

Leaves move back and forth in the breeze. The wheels on a bicycle go around in a circle. All these things are in motion. Motion is a change in position.• Every time you see something in motion, you know a force

somewhere got it going. Every motion is started by a force. Every motion is stopped by a force. Once something is in motion, it will move until some force stops it.

Look at the picture of the city. Each streak of

light shows that an object is moving. What

else could show motion? Harcourt Science

How do forces affect objects?• Forces can change the way things move.• Suppose your chair is next to the wall. You want it to be near

your desk. How would you get it there? Yes, you would move it. Moving it would change the position, or place. • The change in position of an object is called motion. Motion happens any time something moves from one place to another.

This box is in motion. The boys are also in motion.

Houghton Mifflin Kentucky Experience Science

Day 3

Pull

Push

How do forces affect objects?• Think again about moving your chair. To move your chair,

you would have to use a force on it. A force is a push or pull. A push moves something away from you. A pull moves something toward you.• Any change in motion uses a force. You use a force to start

or stop a motion. You use a force to make a motion go faster or slower. You use a force to change the direction of a motion. Using a strong force causes a big change in a motion.

How is this girl using force?

Houghton Mifflin Kentucky Experience Science

1938

PushBoth

Pull

5711

2610124

Balanced and Unbalanced Forces• Suppose you want to move a soccer ball down the field. To start the

ball moving, you have to apply a force. You give the ball a kick with your foot. The ball starts moving. Now suppose you want to stop the ball. Again you have to apply a force. You have to put your foot up and push on the ball to stop it. If you don’t stop the ball, it will keep rolling until some other force stops it.

• Not all forces stop or start motion. Suppose you and a friend push on a box. You push one way. Your friend pushes the opposite way. The forces on the box are balanced, so the box doesn’t move. But if another person starts pushing on your side, the forces aren’t balanced anymore. Now the box moves.

When this girl rides her unicycle, the forces pushing on the left side are the same as the forces

pushing on the right side. This keeps her from falling sideways.Harcourt Science

Day 4

http://www.youtube.com/watch?v=YyJSlcIbd-s

Balanced and Unbalanced Forces Flipbook: 1.Cut on the dotted line.2. Fold on the solid line with the words on the outside.3. Write the definition on the inside flap.4. Draw a picture on the inside of the back, below the definition.

definitiondefinition

Balanced Force

picture

Unbalanced Force

picture

Gravity• There is a force that pulls everything

around us down. That’s why when you drop something, it falls down. The force is called gravity. Gravity is the force that pulls objects toward each other. All objects are acted on by gravity.

Gravity is the force that pulls objects toward Earth. On Earth, all things fall toward the ground. Gravity is the force pulling this egg toward the ground.

Harcourt Science

Day 5

Gravity, Mass, and Weight• The more mass two things have, the more gravity pulls

them toward each other. Earth has a very large mass, so the pull between objects and Earth is large. The moon has less mass than Earth. The pull between the moon and objects is about one-sixth of what it is on Earth.• Weight is the measure of the pull of gravity on an object.

On Earth, you have one weight. But if you were to go to somewhere with a different amount of gravity, you would have a different weight. On the moon, for example, you would weigh one-sixth what you weigh on Earth.

This astronaut is on the moon. His weight is 1/6 what it is on Earth. If he weighs 180 pounds on Earth, he weighs 30

pounds on the moon.Harcourt Science

Gravity

Gravity• One force affects all matter on Earth. It keeps

the juice in your glass and the glass on the table. The force is gravity. • Gravity is a force that pulls objects toward each

other. Earth’s gravity pulls things toward its center. That is why your glass falls to the floor if it falls off the table. Gravity is found between all things. Gravity is not just between Earth and other things.

Gravity pulls the glass bottle toward Earth. Its force is strong. It is strong enough to break the bottle when it hits the floor.

Houghton Mifflin Kentucky Experience Science

Day 6

Gravity• Gravity acts on things without touching them.

How strong gravity is depends on the mass of something. Mass is how much matter something has. • There is more gravity between things that

have more mass. Earth has a large mass, so there is a strong pull between Earth and other things on or near it.

Gravity pulls the children down the slide.

Houghton Mifflin Kentucky Experience Science

Day 7

Paper Cup and Pencils

Friction• Friction is a force that slows down and stops motion

between two things that touch.• Rough things make more friction than smooth things.• Friction can be useful. Friction keeps your feet from slipping

on the floor when you walk. Sometimes friction is not useful. Friction can slow down machines. Many machines use oil to make parts slippery and have less friction.

The blade on this ice skate is smooth. It makes less friction with the ice. The rough tip make more friction with the ice. It helps the skater stop and start.

Houghton Mifflin Kentucky Experience Science

Day 8

Procedure1. Color and cut out dragon racer. DO NOT CUT ON THE DOTTED LINE!

2. Create the ramp with the clothespins and ruler, as shown above.

3. Put a testing surface at the bottom of the ramp. Predict how far in centimeters the dragon will travel on your recording sheet. Set the dragon racer on this surface at the bottom of the ramp. Roll the marble down the ramp. Measure how far in centimeters the dragon racer went. Record. Repeat two more times.

4. Repeat step 3 with a different testing surface until all testing surfaces are used.

5. Discuss findings as a class to explain friction.

6. Using the knowledge gained from the exploration, predict how far in centimeters the dragon racer will go on the real world surfaces. Record predictions.

7. Place your ramp on one of the real world surfaces with your dragon racer at the bottom. Roll the marble down the ramp into the dragon racer. Measure how far in centimeters the dragon racer went. Record. Repeat two more times.

8. Repeat step 7 until all the real world surfaces are used.

9. Complete discussion questions on recording sheet.

Motion• You can tell about the motion of something by its

distance, direction, and speed.• Motion is a change of position. You can tell where

something is by looking at where other things are around it.

The position of the long jumper changes in each picture. Houghton Mifflin Kentucky Experience Science

Day 9

Motion• Every change in motion needs a force. A force is a

push or a pull. It passes energy between two things. Gravity can pass energy between things even when they are not touching. Friction passes energy between things only when they are touching.

Houghton Mifflin Kentucky Experience Science

Vocabulary Review• Review these vocabulary words:

Day 10

Memory Game• Shuffle your cards and

place them face down. One person draws two card trying to get a matching definition.• If they match, the

player keeps the cards. If not, they are replaced and the next player goes.• Whoever has the most

matches at the end wins!

Tug-O-WarYou are about to be in a tug of war competition.•Make a prediction: which class will win and why?• Record and analyze outcome: Who won? Why do you think the team won?

Day 11

• Construct a plan in order for the losing team to win. In order to construct a plan we need to:• Identify the main reason for loss.• Determine the physical attributes of each team (number of students, number of boys vs. girls, body size/structure, athletic ability/strength)• How can we create a greater amount of force, so that the losing team will win? Develop a question/problem. This is what scientists do. • Create a hypothesis. • Think about the following variables/strategies: Does number of, size, order, gender, body type, space, orientation and distance from target.

• Create a plan to test the variable: Discuss the scientific method, establish a control group, and choose one variable to test. Test the variable through Tug O’ War. Use at least three trials and record results. • Discuss the results and form a conclusion.

QUESTION (“What would happen if. . .”)

 

HYPOTHESIS 

 

PROCEDURE Identify

variable group and control

group 

 

  Trial 1 Trial 2 Trial 3

RESULTS   

     

CONCLUSION