Force, Motion and Energy5.6

Electricity—Persuasive When you switch on a light, you are using electricity—a kind of energy. People use electricity to light their homes and buildings, wash and dry clothes, or make motors work. Electricity is a very powerful form of energy.It is easy for electrical energy to flow through some materials. The materials through which electricity flows are called conductors. Copper wires are very good conductors of electricity. Most copper wires you see are coated in plastic. Plastic is an insulator—a material that stops or slows the flow of electricity. Plastic protects us from the electrical current. Glass and wood are also good insulators. Water is a conductor of electricity. For that reason, keep electrical machines away from water. You must use electricity in a safe way.

Prompt:What are some things you can do to use electrical machines safely? Convince your parents that you understand electrical safety at home.

Electricity—Expository When you switch on a light, you are using electricity—a kind of energy. People use electricity to light their homes and buildings, wash and dry clothes, or make motors work. Electricity is a very powerful form of energy.It is easy for electrical energy to flow through some materials. The materials through which electricity flows are called conductors. Copper wires are very good conductors of electricity. Most copper wires you see are coated in plastic. Plastic is an insulator—a material that stops or slows the flow of electricity. Plastic protects us from the electrical current. Glass and wood are also good insulators. Water is a conductor of electricity. For that reason, keep electrical machines away from water. You must use electricity in a safe way.

Prompt:List some materials that are good conductors of electricity. Then, make a list of materials that are good insulators. Display the list for your classmates.

Friction—Expository Roll a marble across a table top and then across a carpeted floor. On what surface does the marble roll better? The marble rolls much better on the smooth, hard floor. The carpet rubs against the marble, creating friction and slowing down its movement. Friction is a force between two objects rubbing together. Smooth surfaces have less friction than rough surfaces. Sometimes we want things to move smoothly. We don’t want or need much friction. Think about the wheels and gears on a bicycle. We keep them clean and oil them so that they can move freely and smoothly. Now think about the handlebars of the bicycle. We don’t want our hands to slide off the smooth metal. The grips on the handlebars keep our hands from slipping. They provide friction.

Prompt:Look carefully at the picture of the couple skating. Explain how friction affects the people and objects in this photograph.

Friction—Descriptive Roll a marble across a table top and then across a carpeted floor. On what surface does the marble roll better? The marble rolls much better on the smooth, hard floor. The carpet rubs against the marble, creating friction and slowing down its movement. Friction is a force between two objects rubbing together. Smooth surfaces have less friction than rough surfaces. Sometimes we want things to move smoothly. We don’t want or need much friction. Think about the wheels and gears on a bicycle. We keep them clean and oil them so that they can move freely and smoothly. Now think about the handlebars of the bicycle. We don’t want our hands to slide off the smooth metal. The grips on the handlebars keep our hands from slipping. They provide friction.

Prompt:Choose either rough or smooth objects to write about. Think of examples and how other things move against them or how they feel.

Gravity—Expository When the car is at the top of a roller coaster, there’s only one way to go . . . down! Gravity is a force that pulls objects towards each other. It is the reason that things roll down, fall down, or stay down. Gravity is all around us. On Earth, we measure the pull of gravity as weight. Your weight, measured on a scale, is actually how much gravity is pulling on you.The bigger an object is, the more gravity it has. In our Solar System, the sun has the greatest mass and the greatest amount of gravity. The Earth has more gravity than the moon, but less than Jupiter. If you weigh 60 pounds here on Earth, you would weigh about 160 pounds on Jupiter, but only 10 pounds on the moon.

Prompt:Read a book or go online to find out about the first moon landing. Write a report on how the moon’s gravity affected how the astronauts moved.

Gravity—Persuasive When the car is at the top of a roller coaster, there’s only one way to go . . . down! Gravity is a force that pulls objects towards each other. It is the reason that things roll down, fall down, or stay down. Gravity is all around us. On Earth, we measure the pull of gravity as weight. Your weight, measured on a scale, is actually how much gravity is pulling on you.The bigger an object is, the more gravity it has. In our Solar System, the sun has the greatest mass and the greatest amount of gravity. The Earth has more gravity than the moon, but less than Jupiter. If you weigh 60 pounds here on Earth, you would weigh about 160 pounds on Jupiter, but only 10 pounds on the moon.

Prompt:Should you be able to go on the largest roller coaster ride at a theme park? Give a few specific reasons why you should be able to ride this coaster.

Light—Narrative Sometimes, when the sun shines are rain, you can see a rainbow. A rainbow may seem like magic in the sky, but it is really caused by the refraction of light passing through water drops in the air. Sunlight is actually made up of many colors of light.A rainbow happens when the sun is low and behind you. As the sunlight travels through the tiny drops of water, the light rays separate out into the colors of the rainbow. You can also separate out the colors with a prism.The colors will always be in the same order: red, orange, yellow, green, blue, indigo, and violet. You can remember the order of the colors in a rainbow by remembering the name ROY G. BIV.

Prompt:What do you imagine is at the end of the rainbow? Write the story of a child who finds out.

Light—Descriptive Sometimes, when the sun shines are rain, you can see a rainbow. A rainbow may seem like magic in the sky, but it is really caused by the refraction of light passing through water drops in the air. Sunlight is actually made up of many colors of light.A rainbow happens when the sun is low and behind you. As the sunlight travels through the tiny drops of water, the light rays separate out into the colors of the rainbow. You can also separate out the colors with a prism.The colors will always be in the same order: red, orange, yellow, green, blue, indigo, and violet. You can remember the order of the colors in a rainbow by remembering the name ROY G. BIV.

Prompt:Imagine a rainbow after a rain. Describe the details of where you see it and what it looks like. How does it make you feel?

Transfer of Energy—Descriptive How do you make an object move? Forces such as a push or a pull make objects move. Forces need energy to happen. Energy can be transferred to an object to make it move. The girl uses the energy in her arms and legs to dance.The force needed to move something depends on how large the object is. What if this girl wanted to do a cartwheel, rather than dance in place? She would have to use more energy to turn a cartwheel. She would use less energy to stand still than if she was moving.

Prompt:Write a description of this girl’s dance program. Where was the program held? Who was watching. What sounds could be heard?

Transfer of Energy—Persuasive How do you make an object move? Forces such as a push or a pull make objects move. Forces need energy to happen. Energy can be transferred to an object to make it move. The girl uses the energy in her arms and legs to dance.The force needed to move something depends on how large the object is. What if this girl wanted to do a cartwheel, rather than dance in place? She would have to use more energy to turn a cartwheel. She would use less energy to stand still than if she was moving.

Prompt:Your school is holding tryouts for a Christmas program. Write an essay to persuade the program director that you should be in the program. Can you dance? Can you sing or play an instrument? What skills do you have that would persuade the director to choose you to be in the program?