9781422284957

Health Science

SCIENCE 24/7

A nimal S cience C ar S cience C omputer S cience E nvironmental S cience F ashion S cience F ood S cience H ealth S cience

M usic S cience P hoto S cience S ports S cience T ravel S cience

SCIENCE 24/7

Health Science

Jane P. Gardner

Science Consultant: Russ Lewin science and Math educator

Mason Crest

Mason Crest 450 Parkway Drive, Suite D Broomall, PA 19008 www.masoncrest.com

Copyright © 2016 by Mason Crest, an imprint of National Highlights, Inc.

All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, taping, or any information storage and retrieval system, without per- mission from the publisher. Printed and bound in the United States of America.

Series ISBN: 978-1-4222-3404-4 Hardback ISBN: 978-1-4222-3411-2 EBook ISBN: 978-1-4222-8495-7

First printing 1 3 5 7 9 8 6 4 2

Produced by Shoreline Publishing Group LLC Santa Barbara, California Editorial Director: James Buckley Jr. Designer: Patty Kelley www.shorelinepublishing.com Cover photo: man: Dreamstime.com/Michael Zhang; background: Dollar Photo Club/Magdal3na

Library of Congress Cataloging-in-Publication Data is available from publisher. Gardner, Jane P., author. Health science / by Jane P. Gardner ; science consultant, Russ Lewin, Science and Math Educator. pages cm. -- (Science 24/7) Audience: Grades 9 to 12 Includes bibliographical references and index. ISBN 978-1-4222-3411-2 (hardback) -- ISBN 978-1-4222-3404-4 (series) -- ISBN 978-1-4222-8495-7 (ebook) 1. Health--Miscellanea--Juvenile literature. 2. Medicine--Miscellanea--Juvenile literature. 3. Medical technology--Mis- cellanea--Juvenile literature. I. Title. RA776.G225 2015 610--dc23 2015004997 IMPORTANT NOTICE The science experiments, activities, and information described in this publication are for educational use only. The publisher is not responsible for any direct, indirect, incidental or consequential damages as a re- sult of the uses or misuses of the techniques and information within.

Contents

Introduction

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Chapter 1: Healing Bones

Chapter 2: Helmets

12 16 20 24 28 32

Chapter 3: Exploding Stars Chapter 4: Sunburns Chapter 5: Staying Fit Chapter 6: Eating Well

Chapter 7: MRI

Chapter 8: Infectious Diseases 36 Chapter 9: Conclusion: Concept Review 40 Find Out More 44 Series Glossary of Key Terms 45 Picture Credits 46 About the Author 47 About the Consultant 47 Index 48

Key Icons to Look For

Words to Understand: These words with their easy-to-understand definitions will increase the reader’s understanding of the text, while building vocabulary skills.

Sidebars: This boxed material within the main text allows readers to build knowledge, gain in- sights, explore possibilities, and broaden their perspectives by weaving together additional in- formation to provide realistic and holistic perspectives. Series Glossary of Key Terms: This back-of-the-book glossary contains terminology used through- out this series. Words found here increase the reader’s ability to read and comprehend higher- level books and articles in this field.

Introduction S cience. Ugh! Is this the class you have to sit through in order to get to the cafeteria for lunch? Or, yeah! This is my favorite class! Whether you look forward to science or dread it, you can’t escape it. Science is all around us all the time. What do you think of when you think about science? People in lab coats peering anxiously through microscopes while scribbling notes? Giant telescopes scanning the universe for signs of life? Submersibles trolling the dark, cold, and lonely world of the deepest ocean? Yes, these are all science and things that scientists do to learn more about our planet, outer space, and the human body. But we are all scientists. Even you. Science is about asking questions. Why do I have to eat my vegetables? Why does the sun set in the west? Why do cats purr and dogs bark? Why am I warmer when I wear a black jacket than when I wear a white one? These are all great questions. And these questions can be the start of something big . . . the start of scientific discovery. 1. Observe: Ask questions. What do you see in the world around you that you don’t un- derstand? What do you wish you knew more about? Remember, there is always more than one solution to a problem. This is the starting point for scientists—and it can be the starting point for you, too! Enrique took a slice of bread out of the package and discovered there was mold on it. “Again?” he complained. “This is the second time this all-natural bread I bought turned moldy before I could finish it. I wonder why.” 2. Research: Find out what you can about the observation you have made. The more in- formation you learn about your observation, the better you will understand which ques- tions really need to be answered. Enrique researched the term “all-natural” as it applied to his bread. He discovered that it meant that no preservatives were used. Some breads contain preservatives, which are used to “maintain fresh- ness.” Enrique wondered if it was the lack of preservatives that was allowing his bread to grow mold. 3. Predict: Consider what might happen if you were to design an experiment based on your research. What do you think you would find? Enrique thought that maybe it was the lack of preservatives in his bread that was causing the mold. He predicted that bread containing preservatives would last longer than “all-natural” breads.

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4. Develop aHypothesis: A hypothesis is a possible answer or solution to a scientific prob- lem. Sometimes, they are written as an “if-then” statement. For example, “If I get a good night’s sleep, then I will do well on the test tomorrow.” This is not a fact; there is no guarantee that the hypothesis is correct. But it is a statement that can be tested with an experiment. And then, if necessary, revised once the experiment has been done. Enrique thinks that he knows what is going on. He figures that the preservatives in the bread are what keeps it from getting moldy. His working hypothesis is, “If bread contains preservatives, it will not grow mold.” He is now ready to test his hypothesis. 5. Design an Experiment: An experiment is designed to test a hypothesis. It is important when designing an experiment to look at all the variables. Variables are the factors that will change in the experiment. Some variables will be independent—these won’t change. Others are dependent and will change as the experiment progresses. A control is nec- essary, too. This is a constant throughout the experiment against which results can be compared. Enrique plans his experiment. He chooses two slices of his bread, and two slices of the bread with preservatives. He uses a small kitchen scale to ensure that the slices are approximately the same weight. He places a slice of each on the windowsill where they will receive the same amount of sunlight. He places the other two slices in a dark cupboard. He checks on his bread every day for a week. He finds that his bread gets mold in both places while the bread with preservatives starts to grow a little mold in the sunshine but none in the cupboard. 6. Revise the hypothesis: Sometimes the result of your experiment will show that the original hypothesis is incorrect. That is okay! Science is all about taking risks, making mistakes, and learning from them. Rewriting a hypothesis after examining the data is what this is all about. Enrique realized it may be more than the preservatives that prevents mold. Keeping the bread out of the sunlight and in a dark place will help preserve it, even without preservatives. He has decided to buy smaller quantities of bread now, and keep it in the cupboard. This book has activities for you to try at the end of each chapter. They are meant to be fun, and teach you a little bit at the same time. Sometimes, you’ll be asked to design your own ex- periment. Think back to Enrique’s experience when you start designing your own. And remem- ber—science is about being curious, being patient, and not being afraid of saying you made a mistake. There are always other experiments to be done!

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1 healing bones “S o, Rania, let’s see how that arm is healing.” Dr. Williams shut the door behind her. Laptop computer in hand, Dr. Williams was ready for Rania’s checkup. Dr. Williams carefully examined her arm, seeing how it moved in different direc- tions. She asked Rania, “Now, remind me again how this happened?” “Well,” Rania looked at her mother. “I was at the skateboard park and was trying to do an ollie off the half-pipe. My foot slipped off the board and I fell, putting my arm out to break my fall.” Looking at her arm, “I broke my fall, but I also broke my arm.” Dr. Williams chuckled under her breath. “I see a lot of that with kids your age. Let’s take a look at the X-rays and see how things are healing.”

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Dr. Williams put two sets of X- rays up on the screen of her laptop. “Here is the broken radius at the time you broke it,” she said, point- ing at the first X-ray. “And here is the X-ray they took today. Yes, it does seem to be healing quite well.” Putting aside the computer, she turned back to Rania and her mother. “Looks good to me.” Rania’s mother had a question. “Doctor. How did it heal that fast? I know when my brother broke his leg last winter skiing, it took months for it to completely heal.” “That’s a good question. It’s important to remember that bones are living. They grow and develop as Rania grows. There are basically three parts to a bone. In the middle of the bone is the marrow . Marrow is a type of tissue . Some marrow makes blood cells, different marrow stores fat that is used as energy. “Surrounding the marrow is what is known as spongy bone. This part of the bone actually does look like a sponge—it has a lot of small holes in it. It is very lightweight but is super strong. The outer layer of the bone is called compact bone. This part of the bone is hard and dense with nerves and blood vessels running through it.” “So will my arm be weaker now?” Rania wanted to know. “Actually, it might be stronger, believe it or not. Not that I am encouraging broken bones or marrow the innermost part of a bone where red blood cells are produced tendon connective tissue that attaches muscle to bone tissue group of similar cells that perform the same function in the body Words to Understand

These X-rays show before and after images of broken arm bones. On the left, the fracture is visible. On the right, healed bones.

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anything,” Dr. Williams explained. Pointing to the site of the break in the newest X-ray, she said, “New bone tissue formed here. The new bone tissue filled in the gap left there by the break. That part of the bone is stronger than it was before.” Rania’s mom smiled. “That’s a relief.” Rania agreed enthusiastically. “Sure is. I can’t wait to get back to the skateboard park and try that trick again. I just know I can do it this time!” Dr. Williams shook her head. “You need to be sure to take care of your bones, young lady.”

Bones There are a total of 206 bones in the human body.

This includes 26 that are in the feet and 54 in your hands! The lon- gest bone is your femur, or thigh- bone. This is also the strongest bone. The smallest bone is found in your middle ear. All the bones in your body are connected to other bones by tendons , except for the hy- oid. This is a U-shaped bone that is found at the base of your tongue!

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Try It Yourself

“Drink your milk!” Ever wonder why grown-ups say that all the time? It’s because of the calcium in the milk and other dairy products. Calcium helps make your bones strong. See what can happen to your bones if they don’t get enough calcium.

Materials: • three clean and dry chicken or turkey bones • three glass jars • vinegar • water • calcium powder

1. Fill each glass jar about ¾ of the way with water. Place 3 tablespoons of vin- egar in one jar. Add 3 tablespoons of calcium powder to another, leaving the third unaltered.

2. Label each jar.

3. Add a chicken bone to each jar, making sure the bones are completely sub- merged in the water.

4. What do you think will happen to the bones in each jar? Write your predic- tions.

5. Wait a week. At the end of that time carefully remove the bones.

6. How do they feel? How do they look? What impact did the vinegar have on the bone? What about the calcium powder?

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helmets 2 “A ctually, going back to the skateboard park brings up another point, Rania. You must be sure to always, always, always wear a helmet while skateboarding. Or while riding a scooter or your bike.” Rania sighed. “I know. My mom tells me that all the time.” Rania’s mom spoke up. “I see kids Rania’s age who ride with helmets on but not buckled. That isn’t going to keep them safe.” Dr. Williams shook her head. “That’s right. I have seen a lot of concussions where the child

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said they were wearing a hel- met but it flew off their head because it wasn’t properly fas- tened.” The doctor also pointed out the importance of making

concussion an injury to the brain which changes the way it works Words to Understand

sure to use a helmet that fits well. She even suggested making sure to have the bike store expert fit the helmet on the user before they leave the shop. The strap should be snug under the chin and fully extended from the helmet. If the straps are loose or twisted, the snap might pop open. A helmet that falls off is no better than no helmet at all. The doctor opened a cabinet in the room and brought out a mangled bicycle helmet. She handed it to Rania. Rania looked at the helmet, her eyes big and round. “Wow. What happened to this?” “And more importantly, what happened to the person who was wearing it?” said her mom. Dr. Williams told the story. A 15-year-old boy was riding his mountain bike on a path in the local woods. He went over a jump, slipped on the landing, and ran head first into a tree. He broke his collarbone and ended up with a concussion . “A concussion, remember, is a serious injury to the brain. It changes the way the brain oper- ates, at least temporarily. Many people get concussions from a hit to the head, like this patient.

This helmet might have saved a life. Bicycle safety experts say that any cracked or damaged helmet should be replaced.

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Contact sports, such as football, see a lot of concussions, too. Usually, over time, the brain heals and the patient fully recovers. But it takes time. It will be a while before this young man can get on his bike again.” Rania’s mom shook her head. “And, that was when he was wearing a helmet.” Turning to her daughter she warned, “Imagine what would have happened to him if he hadn’t been wearing one. Just look at the dent in that helmet. That would have been his skull.” Dr. Williams agreed. “That helmet saved his life. So, Rania, please always wear a helmet!”

The Brain and a Concussion The brain of the average

adult weighs about three pounds. It is “floating” inside the skull, surrounded by fluid. This fluid acts like a shock absorber and protects the brain from minor hits and bumps. However, if the brain moves really fast inside the skull, a concussion occurs. During a concussion, the whole head is moved quickly, which makes the brain hit the inside of the skull. When the head stops moving, the brain bounces back and hits the other side of the inside of the skull. That impact causes the concussion.

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