Gravity - Look Inside

GRAVITY GRAVITY

MASS, ENERGY, AND THE FORCE THAT HOLDS THINGS TOGETHER WITH HANDS-ON SCIENCE ACTIVITIES FOR KIDS

CINDY BLOBAUM

Some of the QR codes in this book link to primary sources that offer first-hand information about the topic. Many photos are often considered to be primary sources as well, because a photograph takes a picture at the moment something happens.

WHICH WAY IS DOWN?

When you think about a cup falling o the counter, what do you picture? Does the cup fall up or down? Why? is might seem like a silly question, but the answer involves a very important concept in the universe—gravity!

ESSENTIAL QUESTION

What force keeps us on the earth?

On Earth, the invisible force of gravity pulls everything toward Earth’s center. Th is is something we all learn at a very young age as we’re fi rst learning to walk. It’s not easy! And gravity continues to be a huge part of our lives, and the world around us, for as long as we live. You can’t turn it on or off. It pulls you down whether you want it to or not. Without it, you would float away!

GRAVITY

WORDS TO KNOW

force: a strength or energy that can change the motion of an object.

gravity: a natural force that pulls objects on and near Earth to the earth.

astronaut: a person trained for spaceflight.

matter: anything that has mass and takes up space.

attraction: an invisible power that pulls things together.

How does gravity keep you safe? What forces can you use to work against gravity, and why do we need to do this sometimes? Why does the position of your belly button matter? How do astronauts work in zero gravity? Can gravity make life easier? You’ll learn the answers to these questions and more in this book!

IT’S ALL A MATTER OF MATTER

Gravity works on all matter. Matter is anything that takes up space and can be measured. Chocolate cake is matter. It takes up space. You can stick a fork in it, and describe how it looks and tastes. You can measure how much it weighs, how large it is, and if it is hot or cold.

Gravity—and balance—keeps these stones standing.

Which Way is DoWn?

What’s it like to live without gravity? Astronauts who have been to space have the answer to that question! Take a look at this video showing how people move and function in a zero-gravity environment. What are some of the challenges these astronauts face? How can they solve some of these challenges? What things might be easier in zero gravity?

Aeon zero gravity

A feather is matter. So are dogs and cats, a car, this book, your body, and even a speck of dust. What about air and other gases? Are those matter? Can invisible things be matter? Yes! Even though we can look right through the air around us and it’s a little trickier to weigh, air and other gases are matter.

The Scientific Method

A scientific method worksheet is a useful tool for keeping your ideas and observations organized. The scientific method is the way scientists ask questions and then find answers. Use a notebook as a science journal to make a scientific method worksheet for each experiment.

Question: What are we trying to find out? What problem are we trying to solve?

Research: What is already known about this topic?

Hypothesis: What do we think the answer will be?

Equipment: What supplies are we using?

Method: What procedure are we following?

Results: What happened and why?

What isn’t matter? Your thoughts and feelings. They are real, but they don’t take up space. You can’t touch or measure them. How about light?

Not matter! Gravity is another thing that isn’t matter. It doesn’t take up space and you can’t touch it.

Gravity’s force is a natural attraction that affects all matter. Gravity pulls all matter closer together. There is gravity between an apple and a banana sitting on a table. There is gravity between a bird and a tree. Most of the time, the pull of gravity between objects is so small that we don’t notice it. But the more matter an object has, and the closer it is, the stronger its pull.

WORDS TO KNOW

gravitational pull: the force of gravity acting on an object. magma: melted lava.

The earth is very, very big. Its gravitational pull is stronger than anything for millions of miles around it. Earth’s gravity pulls you, the air, plants, trees, and even the moon, closer to its center. It keeps our feet on the ground!

In this book, we’ll take a closer look at the phenomenon of gravity and discover how it works, why it works, and the history of the science that brought us to our current understanding of gravity. The deceptively simple concept of gravity provides the basis for our entire existence on Earth, and will play a role in determining which planets we might someday explore! Let’s get started!

Ups and Downs

The sun’s gravity is keeping all our planets in place. The sun even pulls on you! But it is so far away you don’t notice it. Earth is by far the biggest, closest object to humans, so it has the strongest pull on us.

You might think of the earth as being a big ball, but it really isn’t. There are tall mountains and deep valleys. If you took all the water away, it would look bumpy and lopsided. Since the earth is not even, there are some places with more mass and some places with less. This means the pull of gravity is a bit stronger in some places and a bit weaker in others. Sri Lanka, an island off the tip of India, has the lowest pull of gravity on the planet. Scientists think it might be because of the way melted lava, or magma, is moving under the crust. If you visit there, you might be able to jump a bit higher than usual. But you might not feel like jumping at all if you climb to the top of a mountain in the Himalayas, such as Mount Everest. Gravity is stronger than average there. Plus, all that climbing gear you were carrying would pull you down!

Which Way is DoWn?

Earth and the moon had gravitational attraction. It’s the moon’s pull on Earth that is responsible for the tides we see in the oceans! Credit: NASA

Essential Questions

Each chapter of this book begins with an essential question to help guide your exploration of electricity. Keep the question in your mind as you read the chapter. At the end of each chapter, use your science journal to record your thoughts and answers.

ESSENTIAL QUESTION

What force keeps us on the earth?

TEXT TO WORLD

Have you ever watched a rocketship take off? How is the rocketship able to break away from the force of the earth’s gravity?

FINDING DOWN WITH A PLUMB BOB

TOOL KIT

° science journal

° 4 pieces of string, each 3 feet long

° 4 pencils

° 4 different items of different weight (craft stick, magnet, small plastic toy, nail)

In ancient times, such as when ancient Egyptians were building their pyramids, builders used a plumb bob. This tool uses gravity to show a vertical line. People still use them today! A simple plumb bob is a small, heavy object on the end of a string. Plumb bobs always point straight down. Make your own to find out what materials work best for this tool.

› Tie one end of each string to the center of a pencil. Tie one item to the other end of each string. Predict which item will make the best plumb bob.

› Hold the pencil at each end and lift up. What happens to the object at the end of the string? What happens if you tilt the pencil so one end is higher?

› Repeat this with each pencil and item. Record your observations in your science journal.

What’s Happening?

The plumb bob with the most mass is the most affected by gravity and will show the most directo route to the ground.

Try This!

What happens when you try to use each plumb bob near a refrigerator? In a tub of water? In front of a blowing fan? Which item makes the best plumb bob? How might this be a helpful tool for you?

GROWING DOWN

Plant roots grow down and stems grow up. Roots bring plants the water they need. Stems hold leaves up toward the sun so they can make food. Why do roots grow down? Is it because water is stored in the soil or because gravity pulls them down? Make a hypothesis, do an experiment, and record your thoughts on a new scientific method worksheet in your science journal. Then track the results to see if you are right!

TOOL KIT

° science journal

° 16 dried beans (soaked in water overnight)

° 4 paper towels

° 4 zippered sandwich bags

° tablespoon

° stapler

° sunny window with sill or flat surface

° tape

› Fold each paper towel in half, then fold it again. Put one in each bag. It should fill the bottom half of the bag.

› Pour about 2 tablespoons of water into each bag. You want the paper towels to be damp, but not dripping wet.

› Staple each bag in three evenly spaced places about 2 inches from the top of the bag. This makes four spots for seeds.

› In one bag, place a bean in each space between the staples. Change the direction of the bean each time. Start with the first bean facing up, then down, then right, then left. Repeat this in the same order for each bag.

› Zip the bags shut. Find a window that gets a lot of sunlight. Tape one bag to the window with the zipper on top. Tape one bag to the window with the zipper at the bottom. Tape one bag to the window with the zipper facing right or left. Lay one bag flat on the window sill or a flat surface with the same sunlight.

› Check on your seeds every day. In what direction are the roots growing? Is gravity at work? Record your observations. Is it what you predicted? It is possible that some beans might not sprout.

WORDS TO KNOW

vertical: straight up and down.

Try This!

What happens if you change the direction of the bag after the roots have started to grow? Do they continue to grow in the same direction or do they change?

WHAT’S UP? WHAT’S DOWN? WHAT’S KEEPING YOU STEADY?

In Gravity: Mass, Energy, and the Force that Holds Things Together with HandsOn Science Activities, young scientists and engineers ages 8 to 12 explore the invisible but powerful force that is responsible for keeping the entire universe in place—including you! Gravity is the natural phenomenon that makes everything in the universe attracted to everything else. On Earth, that means gravity is why we fall down toward the ground, the reason we have tides, and why we weigh a certain number of pounds.

Hands-on STEAM experiments, fun illustrations, essential questions, fascinating sidebars, and links to online resources and videos in this book are as forceful as gravity itself!

Try these hands-on STEM projects!

• Make a working model of a scale

• Design a building using cantilevers

• Learn some martial arts moves to better understand balance

• Spin a basketball on your finger to learn about balance

books from Nomad Press include the following educational components:

Timeline of important events

Hands-on, science-minded activities

Links to online media

Essential questions

Text-to-world connections

Primary sources, including maps, photographs, and letters

Extensive back matter, including glossary, index, and resources

Guided Reading Levels and Lexile measurements

PUB DATE: OCTOBER 2022

PB: 9781647410100, $17.95

HC: 9781647410070, $22.95

3 Book Hardcover Set: 978161930 9685, $ 67.95

eBook: all formats available, $12.99

Specs: 8 x 10, 112 pages, color interior with illustrations and photography

Ages: 8 12

Grade Level: 3 6

Publicity & Marketing: Co-op funds available

Major national galley mailing

Amazon Merchandising program

National trade advertising, including: - Publisher’s Weekly - Booklist - School Library Journal

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For more information about these books, contact Nomad Press: a@nomadpress.net, 802.649.1995