SC.5.P.13.1Force and

Motion

SC. 5.P.13.1Benchmark: Identify familiar forces that cause objects to move, such as pushes or pulls, including gravity acting on falling objects.Essential Question:How is the motion of an object affected by the forces acting upon the object?Vocabulary:force magnetic forcegravity friction

Types of ForcesA force is a push or pull that can cause an object to start moving, stop moving, or change direction. The more force that is applied to an object, the greater the change in the object's motion.

An object's motion is the result of force. Forces make it possible to push, lift, press, pull, and squeeze. In nature, there are a few main kinds of forces, including the following:

• pushes and pulls• friction• magnetism• gravity

Push

A push is a force that can cause something to move away from the person or object pushing it. Pushing can only take place when objects are touching.

PullPulling- Pulling is a force that can cause something to move toward the person or object pulling it. Like pushing, pulling can only take place when objects are touching.

FrictionWhen two objects are touching and one of them tries to move, friction is the force that acts in the opposite direction of the motion. This means that friction is a force that stops motion. It can also create heat. For example, when a rolling marble is in contact with the sidewalk, friction slows the movement of the marble, eventually making it stop.

Click on the camera viewer to watch a video segment about friction.

C:\Documents and Settings\linda.vendur\D

SummarizingAnswer the following question in your

notebook:A catapult is a device in which tension

is suddenly released to hurl an object. What forces are acting on the catapult?

If you put two magnets together with different poles pointing towards one another, the magnets will ATTRACT (pull towards) each other.

If you try to put two magnets together with the same poles pointing towards one another, the magnets will REPEL(push away from) each other.

Opposites Attract!

MagnetismMagnetism is an attractive or repulsive force between magnetic materials. Magnets have two poles, a North pole and a South pole. When two magnets are placed close together, like poles will repel one another and opposite poles will be attracted to one another. Magnetism is a force that can act from a distance, depending on the strength of the magnet.

Gravity

Gravity is the force of attraction that exists between any two objects that have mass. It is the basic force of the Universe. Gravity keeps the planets orbiting around the Sun, and it pulls objects on Earth toward the Earth's center. For example, gravity causes fruit on a tree to fall to the ground.

Gravity pulls objects towards the Earth center.

Force is needed for motion and direction

A force is a push or a pull that can start, stop, or change the direction of an object's motion.All motion begins with a force.Force is needed to stop an object's motion. For example, the brakes of a car apply a force to the car's wheels in order to help the car stop.Force is also needed to change the direction of an object's motion.

Motion

Motion is a change in position. The position of an object that is in motion is always changing. It does not stay in the same place. The direction that an object is moving might change or it might stay the same.

Direction

Direction is the path along which something is moving. Words that can be used to describe the direction of an object's movement include:

up or down• left or right• north, south, east, or west 

Force & Motion The motion of an object is affected by the strength of a push or pull and the mass of the object. A force is a push or a pull that can move an object. Forces are needed to start, stop, or change the direction of an object's motion. The more force that is applied to an object, the greater the change in the object's motion. In other words, the harder an object is pushed, the farther and faster it will move.But, if the same amount of force is used to move two objects that weigh different amounts, the lighter object will usually move farther and faster before it stops than the heavier one will.

Balanced Forces vs. Unbalanced Forces

If the forces applied to an object are balanced, the motion of the object does not change. If an object is sitting still, it will continue to stay still. If an object is moving, it will continue to move in the same direction and at the same speed.

If the forces applied to an object are unbalanced, the motion of the object will change. The object could start moving, stop moving, change direction, or change speed. For example, imagine an object is sitting still. If it is given a large push from the left and a small push from the right, the object will begin moving to the right.

How your Notes Should LookForce force is a push or pull that can cause an

object to start moving, stop moving, or change direction

Kinds of forces:

pushes and pullsfrictionmagnetismgravity

Push is a force that can cause something to move away from the person or object pushing it. Pushing can only take place when objects are touching.

Pull is a force that can cause something to move toward the person or object pulling it. Like pushing, pulling can only take place when objects are touching.

How your Notes Should LookFriction is a force that stops motion

Magnetism is an attractive or repulsive force between magnetic materials.

Gravity is the force of attraction that exists between any two objects that have mass. .

Motion begins with a force..

How your Notes Should Look

Direction is the path along which something is moving.

Force and Motion

The motion of an object is affected by the force of a push or pull and the mass of the object.

• The more force that is applied to an object, when it is pushed, the farther and faster it will move.

• If the same amount of force is used to move two objects that mass different amounts, the lighter object will usually move farther and faster before it stops than the heavier one will.

How your Notes Should Look

Balanced Forces

When the motion of the object does not change. If the object is moving it keeps moving if it still it stays still.

Unbalanced Forces

the motion of the object will change. The object could start moving, stop moving, change direction, or change speed.

Guided PracticeThree Stay One Stray

Answer questions with your group. When finished designate one person to go from group to group to compare answers and explain.After the stray comes back to their group the stray shares the other responses.

1. A circus acrobat was shot out of a cannon. As she flew across the room, she began to fall down toward the net.What force caused the acrobat to fall down toward the net?

A. frictionB. heatC. gravityD. wind

Guided Practice

1. C Gravity is the force that pulls objects to the ground.

Guided Practice

2. A rolling ball will slow down until it finally stops. What force slows down and stops the ball?

A. gravityB. solar powerC. frictionD. speed

Guided Practice

Friction is the force that slows objects down and causes them to eventually stop.

2. CGuided Practice

3. A soldier with a parachute jumped out of an airplane. After he opened his parachute, he fell more slowly.

What upward force slowed down his fall? A. gravity B. friction C. air resistance D. weight

Guided Practice

Remember dropping the flat sheet of paper? The air resistance slowed down its fall to the ground. A parachute acts the same way, making it safe for people to jump out of planes.

3. CGuided Practice

4. Mike lifted a heavy box. What force did he have to overcome to move the box upward?

A. gravity B. air resistance C. friction D. muscular

Gravity is the force that pulls objects to the ground, but it is also the force that holds objects, and us, to the ground.

4. A

Summarizing

How is the motion of an object affected by the forces acting upon the object?

Answer this question using the following words.

gravit

y

friction

push or pull forc

e

magnetic force

Check Your Understanding

William used a hammer to pound a nail into a wooden board. When the nail was about halfway through the board, he stopped and turned the board upside down. The nail stayed in place in the board. Which of the following acts on the nail to keep it in place in the board? A. friction B. gravity C. magnetism D. mass

Dawn has a bar magnet.

What will happen when she brings the north end of her magnet to the south end of Brittany’s magnet?

A. They will attract B. Nothing will happen C. They will repel D. Sparks will fly

Check Your Understanding

Juan and Kathleen bought model rocket kits. They built identical rockets with identical engines. Juan, however, glued small pieces of a broken bicycle reflector to his rocket to make it more visible in the sky.

If everything is the same on both rockets except for the reflector pieces, which rocket will travel higher when they are launched at the exact same time?

Check Your Understanding

Check Your Answers1. A. Friction2. A. They will attract3. Kathleen’s Rocket

Candice is riding her mountain bike to school the morning after a heavy rainstorm. Just before she gets to school, there is a grassy slope she usually rides up easily. Today, when she gets to the slope, she keeps pedaling, but her bike doesn't go up the hill.

Explain why Candice's mountain bike wouldn't go up the slope easily.

Exit Slip

Internet Resources for

Force and Motion

TEACHER RESOURCE: Force and Motion Theme Page

This website has numerous links to activities and lessons dealing with force and motion. It has material appropriate for all learners from beginning to advanced.

BBC Science Clips: Pushes and Pulls

An interactive website that looks at the effect of a push and a pull on a toy cart. BBC Science Clips: Force and Movement

In this interactive game, students are able to explore the concept of force and movement by manipulating a car toy in an obstacle course. BBC Science Clips: Magnets and Springs

This website allows students to learn about the forces involved with magnets. ThinkQuest: Force and Motion

This website gives students background information on different forces and the concept of motion. Some of the readings may be above the appropriate grade level.