Skeletal System Written by Karl Muster Visited classroom October 2013 Topics: biology, skeletal system, nutrition Required knowledge: "strength", "molecule", "tissue" Grades: 1st-3rd Materials

• 1 skeleton puzzle per group (~3 students) or one for the class • glue sticks or round-head fasteners • black paper • dish soap • food coloring • small shallow container (like a lid) per group • 1/2 cup milk per group • pictures to pass around to students or show on projector

Preparation Cut out the skeleton puzzle pieces if you are limited on time (if you are visiting a classroom). You can decide if you want to do small puzzles or large ones. The templates can be found on the website. Part 1: The Human Skeleton The skeleton is a name for all the bones in your body. Bones do many useful things for you. The most obvious one is that it provides support. Without your skeleton, you would be a pile of mush. Secondly, your muscles can only pull on things, and your skeleton gives something that the muscles can attach to and pull on, or else muscles wouldn't do anything. Thirdly, bones give you protection. Many of your important organs are protected by your rib cage, and your brain is protected by your skull. There are some extra things that your bones do for you. They are important for storing nutrients, which are the parts of healthy foods that your body uses. When you eat, you "digest" the food to get nutrients, but your body doesn't use it all up right away. Most of them are sent to your bones for storage when you need it. Also, inside of your bones is tissue called "marrow", which is where your blood is made. It makes the parts of blood that transport oxygen through your body and also the parts that fight germs when you get sick. ACTIVITY: Hand out black paper and the puzzle pieces to each of the student groups. The students will have a fixed amount of time to assemble the puzzle in their groups. They might need some assistance. Another option is to print large pieces and get volunteers to add a bone to the skeleton one at a time. Using round paper fasteners for the joints will allow the skeleton to move, which can be a useful demonstration. Go over the names of each one at the end. You can also go over what each one does.

Go over some random facts about skeletons for fun. You can pose these either as facts or questions.

• Are teeth bones? No. • How many bones in adult human? 206 • Smallest Bone? (stapes- middle ear) small as a grain of rice • Biggest bone? (femur- thigh bone) • How many Vertebrae do you have (24) • There is only one bone that does not form a joint, the hyoid which is near your throat • Most of the bones in your body are in your hands and feet • Who has more bones, a baby or an adult? Babies have about 300 bones, but they

eventually fuse together. Babies' bones are really breakable, so you have to be careful when holding a baby.

• Are bones alive? Yes, when you break a bone, it can heal after a few months Part 2: Joints The place where bones come together are called "joints". They can come together in different ways, and that determines how you can move, and some of these joints are very important for daily activities. ACTIVITY: To demonstrate why certain joints are important, these are some activities that the students can try. Have them get in a circle and play Simon Says. You may need to pick volunteers to try each one, especially for the jumping ones if you're not on the ground floor.

• Walking without knee joint • Walking without ankle joint • Touching head with arms straight • Touching feet with knees straight • Picking something up without thumbs (Grab thumb with other hand) • Pick up pencil with your fingers glued together: like seal flippers • Jumping without knees • Jumping on heels (no ankle or foot joints) • Running on heels

There are several types of joints. Some joints are a combination of several kinds:

1. Ball and Socket - full circular movement; ex. arm/shoulder, leg/pelvis 2. Hinge - movement in two directions; ex. elbow 3. Pivot - circular rotation ex. mandible/skull 4. Plane - sliding movement, usually not much movement ex. vertebrae, some hand joints 5. Fibrous - doesn't move ex. skull bones, ribs

Some joints, like between your vertebrae and in your pelvis, have a tissue called "cartilage" that acts as a cushion. This is why your spine is flexible. It's also the same stuff that your nose and ears are made of. Sharks have no bones; their skeleton is made up of cartilage.

Part 3: Calcium Again, your bones are where many nutrients are stored. Calcium is a nutrient that is stored in the bone to make bones strong. It is also used in other parts of the body, like your blood, brain and muscles. Dairy products like milk and cheese are good sources of calcium and other nutrients that your bones need. ACTIVITY: Magic Milk (see module on website). This lets students see that milk has nutrients. The soap pulls the nutrients apart, which pushes the milk away from it. That's why the milk seems to flow outwards from the soap.