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Investigation: Broken BonesInvestigation-Broken-Bones

  • Subject:
  • |
  • Grade(s): 6-8
  • |
  • Duration: One or two class periods

Lesson Plan Sections


Students will understand the following:
1. There are a variety of injuries to the human body.
2. The process of maintaining healthy bones.
3. The healing process of a broken bone.


For this lesson, you will need:
KWL chart (Divide a piece of paper into three columns: What We Know; What We Want to Know; What We've Learned.)
colored pencils/markers
laminated "signs" of vocabulary words used in the lesson (optional)


1. Place your KWL chart in front of the class and ask students to brainstorm what they already know about bones: What are bones made of? Are bones solid? What makes bones strong? What do bones do for us? (Write their responses in the first column of the chart, "What We Know.")
2. Ask students what they want to find out about bones. (Write their questions in the second column of the chart, "What We Want to Know.")
3. Next, describe the importance of our skeletal system, including information such as the following:
  • It is responsible for creating cells that help keep us healthy (white blood cells).
  • It protects our vital organs.
  • It supports our muscular system, allowing us to move.
4. Explain that in order for bones to maintain themselves, they must constantly break down and rebuild the collagen and minerals that they are made of. Introduce the vocabulary words osteoclast and osteoblast.
  • Cells called osteoclasts are multinucleated cells that eat away the bone's mineral coating and collagen. You can think of them as "bone destroyers."
  • Cells called osteoblasts are cells that lay new collagen and coat the bone with fresh minerals. You can think of them as "bone creators."
5. Describe the process of bone maintenance: Osteoclasts break down the "old" collagen and minerals that make up healthy bones. Then the osteoblasts follow and lay down fresh collagen and minerals. The process is never ending. As a result of this constant breakdown and replacement, human bones are never more than 20 years old.
6. Explain that although bones are very strong, they do sometimes break. Describe what happens to the body when a bone is broken:
  • The injury is flooded with natural painkillers called endorphins, which temporarily block out pain.
  • An injury will swell because the body is sending extra oxygen and nutrients to the injury to begin the healing process.
  • A large hematoma, which is a collection of blood, surrounds the break in the bone.
  • Stem cells , which are responsible for making new cells, usually divide every one to two days. Now that there is an injury, they will divide every three minutes.
  • Within four weeks the hematoma will harden around the break, making the injured area extra strong.
  • Over the next several months, osteoclasts will "eat away" the hardened hematoma and the injury will be repaired.
  • Within a year of the injury, the bone will be almost as strong as it was before the break!
7. Have students draw (in cartoon style) the process of bone repair following a break, making sure to incorporate the new vocabulary words they have learned.
8. Return to the KWL chart, and ask students to share facts they've learned about bones. (Write their responses in the third column of the chart, "What We've Learned.")

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Adaptations for Older Students:
Have students research the body's healing process and create a visual time line of the steps involved as a bone repairs itself. The time line should begin at the moment of injury and end with the injury healed. Encourage them to identify the chemicals and cells involved in each stage of the process.

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Discussion Questions

1. According to the Centers for Disease Control and Prevention, more males than females are affected by serious injury each year. Why do you think this is so?
2. Bones regenerate faster in children than they do in adults. What is responsible for this difference?
3. Analyze the importance of endorphins at the time of injury. How would a serious injury be different if there were no such chemical? How might it help the injured person that endorphins are not long lasting?
4. Why does an injury swell? Can you think of any advantages of this swelling? Are you more likely to ignore an injury that does not swell?
5. Explain the idea that your bones are never more than 20 years old.
6. Name one way the body responds when a bone is broken. How does this response help the injured person?

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Evaluate students' learning by asking them to write a paragraph describing the internal healing process of a broken bone. Students should be required to use at least three of the vocabulary words from the lesson.

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Say What?
Write vocabulary words on index cards. Divide the class into groups, giving each group one card. Give the class 5 to 10 minutes to come up with a catchy way to enable other students to remember their word. Groups may develop a poem, rap, story, or skit—encourage them to be creative! Have each group present its "memory trick" to the class.

If We Had No Bones
Review the different purposes of bones with your class. Have students write and illustrate a short paragraph describing what our bodies would be like without bones. Then have them research the skeletal structures of different animals. Do all animals have bones? How are bones different among various animals? How are they alike?

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Suggested Readings

All About Bone: An Owner's Manual
Irwin M. Siegel, Demos Medical Publishing, 1998.
The author is an orthopedic surgeon who writes about what bone is, what it does, and what can go wrong with it, including fractures and a variety of diseases. How each part of a human skeleton works is explained as well as how bones heal.

Bones: The Unity of Form and Function
R. McNeill Alexander, Macmillan, 1994.
Bones are marvels of engineering, strong yet lightweight and perfectly shaped for their duties. This over-sized book is an exploration of the structure, composition, and movement of bones of all animals including the human animal. Museum-quality, full-page, color photographs of everything from fish jaws to rattlesnake fangs and from a lion's retractable claws to a human hand illustrate how bones do everything they do.

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Learn about and view all types of fractures which can affect children. Then see how everything grows back together again.

Bumped, Bruised, and Worse: Preventing and Treating Kids Sports Injuries
While adults most often will tear a muscle or ligament when they fall or collide, kids are far more likely to break a bone. Want to know what to do next? Check the Kids Health section of Discovery Health to find out

Childhood Injury Fact Sheet
Although not all childhood injuries result in broken bones, many do. Find out more about risks, types and causes at this site provided by the Center for Disease Control.

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Click on any of the vocabulary words below to hear them pronounced and used in a sentence.

speaker    endorphins
Definition: Our body's natural painkillers.
Context: Endorphins help us manage the immediate pain from injuries, enabling us to get out of danger, but they are not long lasting.

speaker    hematoma
Definition: A swelling or collection of blood at the site of an injury resulting from the break of a blood vessel.
Context: A collection of blood, not necessarily a bruise, a hematoma is necessary to repair bones.

speaker    osteoblast
Definition: Cells responsible for adding new collagen and minerals to bones.
Context: Osteoblasts are responsible for the second half of skeletal maintenance; these cells are known as the "bone creators."

speaker    osteoclast
Definition: Large cells responsible for removing minerals and collagen from bone.
Context: Osteoclasts perform the first step in bone maintenance; they are known as the "bone destroyers."

speaker    stem cells
Definition: Cells that are responsible for making new cells, normally dividing every one to two days.
Context: When a bone is injured, stem cells divide at a much faster rate—once every three minutes.

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This lesson plan may be used to address the academic standards listed below. These standards are drawn from Content Knowledge: A Compendium of Standards and Benchmarks for K-12 Education: 2nd Edition and have been provided courtesy of theMid-continent Research for Education and Learningin Aurora, Colorado.
Grade level: 6-8
Subject area: Health
Understands the fundamental concepts of growth and development.
Understands how the human body changes as people age (e.g., muscles and joints become less flexible, bones and muscles lose mass, energy levels diminish, senses become less acute).

Grade level: 6-8
Subject area: Health
Knows how to maintain mental and emotional health.
Knows characteristics and conditions associated with positive self-esteem.

Grade level: 6-8
Subject area: Health
Knows essential concepts and practices concerning injury prevention and safety.
Knows strategies for managing a range of situations involving injury (e.g., first-aid procedures, abdominal thrust maneuver, cardiopulmonary resuscitation).

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Lynn Wiegand, current health education teacher, Rocky Hill Middle School,Clarksburg, Maryland.

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