Human Bones BROWARD COUNTY ELEMENTARY SCIENCE BENCHMARK PLAN ACTIVITY ASSESSMENT OPPORTUNITIES. Grade 4 Quarter 3 Activity 21

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1 activity 21 Human Bones BROWARD COUNTY ELEMENTARY SCIENCE BENCHMARK PLAN Grade 4 Quarter 3 Activity 21 SC.F The student knows that the human body is made of systems with structures and functions that are related. SC.H The student knows that to work collaboratively, all team members should be free to reach, explain, and justify their own individual conclusions. SC.H The student knows that a model of something is different from the real thing, but can be used to learn something about the real thing. ACTIVITY ASSESSMENT OPPORTUNITIES The following suggestions are intended to help identify major concepts covered in the activity that may need extra reinforcement. The goal is to provide opportunities to assess student progress without creating the need for a separate, formal assessment session (or activity) for each of the 40 hands-on activities at this grade level. 1. Ask, If your leg bones were really connected like this activity s model bones were, do you think you would be able to run faster than you can run now? (No, your stride would be too wide to control.) Have students use their model bones to test this out. Then ask, What are some things the skeleton of bones in your body allows you to do? What are some things you do to protect your skeleton from damage? (Accept all reasonable responses.) 2. Use the Activity Sheet(s) to assess student understanding of the major concepts in the activity. In addition to the above assessment suggestions, the questions in bold and tasks that students perform throughout the activity provide opportunities to identify areas that may require additional review before proceeding further with the activity. broward county hands-on science Quarter 3 255

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3 activity 21 Human Bones OBJECTIVES Students observe and discuss the functions of various bones in the human body. The students identify some of the bones in the human body observe that bones support the body and protect vital organs observe that bones are connected to one another at the joints construct a model of the leg SCHEDULE About 45 minutes VOCABULARY clavicle cranium femur fibula humerus joint mandible patella pelvis MATERIALS radius rib scapula skeletal system skeleton sternum tibia ulna vertebra For each student 1 Activity Sheet 21, Parts A and B 2 paper fasteners For each team of two 1 pair scissors* For the class 1 cardboard skeleton 1 model skeleton 1 poster, Human Skeleton 1 transparency, skeleton *provided by the teacher PREPARATION Make a copy of Activity Sheet 21, Parts A and B, for each student. Each student will need two paper fasteners. Each team of two students will need a pair of scissors. Hang the Human Skeleton poster where students can see it. Allow students access to the model skeleton. BACKGROUND INFORMATION Bones make up the skeleton, which is the framework of our body (see Figure 21-1). Bones support the body, protect vital organs, and provide a place for muscles to attach. The skeleton of an adult human consists of 206 bones: 29 in the skull including the bones in the face and middle ear; 26 in the spine (vertebrae); 29 in the rib cage (ribs and sternum); 60 in the shoulders, arms, and hands; and 62 in the hipbone (pelvis), legs, and feet. Human bones are made of protein and calcium phosphate, in about equal amounts. The protein component is the bone marrow, blood, blood vessels, and nerves. The calcium phosphate component is the hard, whitish, shell-like exterior you see when you look at a bleached and dried bone. The largest bone in the human body accounting for about one-fourth of body height is the thigh bone (femur) in the leg. The three smallest bones each less than 2 mm long are in the middle ear. broward county hands-on science Quarter 3 257

4 cranium mandible scapula clavicle sternum ribs humerus pelvis radius ulna vertebrae carpals metacarpals phalanges femur patella tibia fibula Figure The human skeleton. 258 activity 21 Human Bones tarsals metatarsals phalanges

5 Activity Sheet 21, Part A Activity Sheet 21, Part B Human Bones Human Bones 1. Label the bones of the human skeleton. 2. Cut out the bones. Put them together to make a model as shown in the picture. Use your model to see how the joints move. cranium scapula ribs mandible clavicle sternum humerus paper fastener paper fastener A B A pelvis radius ulna carpals metacarpals phalanges vertebrae femur tibia fibula patella tarsals metatarsals phalanges B 1 Guiding the Activity Write the word skeleton on the board. Students will probably know that a skeleton is made up of different bones. Ask, What do you think bones do? Additional Information Students may say that bones support the body and that certain bones protect vital organs. 2 Write the words skeletal system on the board. Tell students that the skeletal system consists of the bones that provide support for the body. In an adult human, the skeletal system consists of about 200 bones. Distribute Activity Sheet 21, Part A, to each student. Display the transparency of the human skeleton and pronounce the name of each bone. Encourage students to say the names of the bones aloud with you and to write these names in the appropriate spot on the diagram in Activity Sheet 21, Part A. broward county hands-on science Quarter 3 259

6 Guiding the Activity Starting at the head and working your way down, identify the cranium (skull) and the mandible (lower jaw). Point to the skull and ask, Which organs are protected by the skull? Call their attention to the clavicle, sternum, ribs, and vertebrae. Ask, Which organs are protected by these bones? Explain that every adult human has twelve pairs of ribs and twenty-six vertebrae. Mention that the clavicle is also called the collarbone, the sternum is also called the breast bone, and the scapula is often referred to as the shoulder blade. Now focus on the arms. Tell students to feel the bones in their own arms. The long bone of the upper arm is called the humerus. The lower arm (forearm) has two bones: the ulna and the radius. The hand is made of many small bones. Next, focus on the legs. Our legs are attached to our pelvis, or hipbone. The femur is the thigh bone and the patella is the kneecap. The lower leg has two bones: the tibia (shin) and the fibula. The foot is made of many small bones. Ask, Which bone do you think supports the most weight? Distribute Activity Sheet 21, Part B, and two paper fasteners to each student. Divide the class into teams of two and give each team a pair of scissors. Have students identify the bones pictured on the activity sheet, and then have them cut out the bones. Tell them to use paper fasteners to join the upper and lower leg bones at the hip and knee. 260 activity 21 Human Bones Additional Information Students will probably state that the brain is protected by the skull, but make sure they know that the eyes and inner parts of the ears are also protected by the skull. The heart and lungs are protected by the ribs and sternum. The spinal cord is protected by the vertebrae. Students may know that the femur supports the most weight.

7 8 9 Guiding the Activity Write the word joint on the board. Ask, What are joints? What is their function? Tell students that joints are where adjoining bones meet. By enabling the bones to sit at different angles to one another, joints make it possible for the body to bend, kneel, twist, and turn. Ask students to investigate how the parts of their leg models move. Ask, Which parts represent joints? Ask students, How is the model leg different from a real leg? Ask, Where in the human body are the bones and joints that allow the most precise movements located? Explain that short bones and the joints between them permit delicate movements. Have students compare the movements of their fingers and toes with those of their arms and legs. Additional Information Accept all reasonable answers. The two paper fasteners represent joints in that they are the points at which the bones meet and they enable connecting bones to move in relation to one another. Students will probably say that the model leg moves in ways a real leg cannot. Students will probably say that they can perform precise movements with their hands and feet. R EINFORCEMENT Have students work together to assemble the cardboard skeleton. SCIENCE JOURNALS Have students place their completed activity sheets in their science journals. C LEANUP Return the transparency to the kit. Discard the paper scraps. Have the class display their leg models, or take them home. broward county hands-on science Quarter 3 261

8 Connections Science Challenge The following demonstration illustrates the importance of calcium and phosphorus in strong bones: Let students examine uncooked leg or thigh bones from a chicken. Safety Note: Make sure that you remove all the meat and wash the bones thoroughly before letting students handle them. Ask students whether they can bend a bone without breaking it. (no) Then put the bones in a jar filled with vinegar. After at least three days, remove the bones, rinse them with water, and let students try to bend them again. (They will bend.) Ask students to suggest a reason for the soaked bones flexibility. (The acidic vinegar dissolved the calcium and phosphorus in the bones, leaving them soft and flexible.) Ask students to explain why calcium and phosphorus are important minerals in their diet. (They help build strong bones.) Science Extension Obtain several long bones from a butcher shop or the meat department of a supermarket. Ask the meat cutter to saw some of the bones crosswise and the rest lengthwise. Let students examine the cut bones and describe what they see. The crosswise cut shows the cylindrical shape of a long bone s shaft and its hollow, marrowfilled core. The lengthwise cut shows the core and also the denser bone tissue at the knuckle end of the bone. Provide magnifying lenses so students can observe that bone actually has tiny spaces in it. Safety Note: Make sure students wash their hands thoroughly after handling the bones. Have students do the following activity to observe the relationship between a long bone s cylindrical shape and its weightbearing function: Roll a sheet of paper into a narrow tube and fasten it with tape. 262 activity 21 Human Bones Make an identical second tube. Lay one tube between two books like a bridge and then put weights on the middle of the tube until it buckles. Stand the second tube upright and put weights on the upper end until the tube buckles. Which tube bore the most weight before it collapsed? (the upright tube) In a follow-up discussion, help students see the similarity between the upright tube and the long weightbearing bones of the upper and lower leg. Science and the Arts Provide a wide variety of materials for students to use in making pictures of the human skeleton, using the diagram on the activity sheet as a model. Encourage students to be creative. For example, some students could make a skeleton by gluing lengths of white paper straws to black construction paper. Other students may enjoy drawing bones on an outline they have traced of their own body. Science and Math Encourage interested students to investigate how many vertebrae make up the spinal column, how many ribs are in the rib cage, or how many bones make up the skull. Some students may want to research the number of bones in the entire skeleton (206). Does the number depend on the person s age? Science, Technology, and Society Many surgical techniques and artificial devices have been developed to repair or replace joints that are damaged by disease or injury. Encourage interested students to research such techniques and devices, including the use of the arthroscope in reconstructing a joint and knee or hip replacement surgery.