Chapter 15: Motion Miss Barnes

Today you will need: Science Book Force and Motion Glossary Pencil Listening ears

Define it! Get your Force and Motion Glossary out! Find the word: Write the definition: The action of changing place or position (moving).

How would you describe motion? Motion is everywhere: You move everyday in one way or another. Walking down the hallway Roll over in bed Heart Beats Eyelids blink up and down

Brainstorm With your shoulder partner, think of all the ways you see motion everyday!!!! Create a list to be turned in at the end of class! Write your names on it. This is your ticket out the door.

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What causes motion? Motion is caused by force. What is force?

Define it! Get your Force and Motion Glossary Out! Find the word: Write the definition: Force is a push or pull that acts on an object.

Different kinds of motion? Can there be different kinds of motion? YES!!!!

Straight Line Motion Objects can travel in a straight path. Baseball player racing to home plate. Trains on a track.

Curved Motion Objects can travel in a curved path or circular motion. A car turning a corner. The Earth moving around the sun.

Vibrating Motion Objects can travel back and forth. A guitar player plucks a guitar string. A rubber band that has been plucked.

Define it! Get your Force and Motion Glossary out! Find the word: Speed Write the definition: Speed is the rate at which an object changes position.

Speed Speed is the main way we describe motion. Speed is how far an object moves during a certain amount of time. Average speed= Distance/ Time

Speed If I say: The train traveled 60 miles per hour (mph). This means: The train traveled a distance of 60 miles in one hour. If I say: Bob types 50 words per minute (wpm). This means: Bob can type 50 words in one minute of time.

Brainstorm With your shoulder partner, think of other speeds you have heard of. Create a list to be turned in at the end of class! Write your names on it. This is your ticket out the door.

Speed and Force The speed of an object depends on the force applied to the object and the mass of the object. Which do you think would have a faster speed? A 2lb rock falling off of the Empire State building. A 10lb rock falling off of the Empire State building.

Speed and Force A 10lb rock falling off of the Empire State building. The rock with the larger mass would fall more quickly than a smaller rock.

Speed and Force An object with a greater mass will require a greater force to move it. It will take more force to move a car than a book. Why? The masses are very different. The car has a much greater mass.

Speed and Force If you have two objects with the same amount of mass, but a stronger force is applied to one? Which will travel fastest? The object with the greater force applied will travel faster. The force applied to an object, affects its speed.

May the force be with you…

Gravity Gravity pulls every object on Earth towards the Earth’s center. Because of gravity, the Earth is pulling on objects without even touching them. An object’s weight is the amount of gravitational force between it and the Earth.

Review On your sheet of paper answer the following question: If we were to travel to other planets, would our weight change? Why?

Gravity The gravitational pull of an object to the earth is called weight. We measure weight with a scale. Where have you seen a scale before? The scales we use in our classroom are called spring scales, because they use a spring to determine the weight of an object.

Magnets are forces too… Magnetism is a force that pushes and pulls on other objects. This force is greatest at the magnet’s poles. Materials that are attracted to magnets, will pull towards the magnet.

Magnets are forces too… The north pole of one magnet will attract the south pole of another magnet. Opposites attract!!!! The north pole of two magnets will push away. So will two south poles! 

Magnets Activity

Discuss it!!! Turn to your shoulder partner and discuss: How do you think static electricity could be a force? You have 1 minute! GOOOOOO!

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Answer: Static electricity causes a build up of charges. Just like with magnets, opposites attract! Positive charges are attracted to negative charges and can cause a pull between the two objects. Also like magnets, like charges repel from each other. This also causes motion as the two objects move away from one another.

Friction Friction is the force that results when two materials rub against each other. Friction slows down the motion of an object or it stops it from starting to move.

Let’s Experiment! Walk around in your shoes. Slide your feet across the floor. What does it feel like? Take off your shoes! Now slide around the floor in your socks. Is there a difference? The texture of the soles of your shoes is different from the texture of your socks. Friction is greater between your shoes and the floor than between your socks and the floor.

Reflect Why do you think there is a difference when you rub your feet on the carpet and when you rub them on the floor? What could cause this difference? Would it be easier to run in your socks or in your shoes? Why?

Friction Friction causes motion to slow or stop or not move at all. Friction is a force! The texture, shape, or speed of one object can affect the amount of friction with another object.

Work, What’s that? What do you think of when you hear the word “work”? To most people, “work” reminds them of a job or career. The scientific meaning of “work” is much different. The energy used when a force moves an object.

Work: If the force applied to an object does not make the object move, then no work has been done. Holding an object in place can require a force, but since the object did not move, no work is done.

Friction Activity