Skeletal System
Lesson Goals:
The kids will learn what purpose the skeleton serves in our bodies, some basic skeletal
vocabulary, and get an introduction to some of the types of bones in bodies.
Materials
Bone Sorting Sheets
Owl Pellet
Plastic Tweezers
Wooden Skewer
Cardboard Sheet
Tacky glue
Pen
Part I: Introduction (5-10min)
The kids will go over their worksheet, which will just ask them to name as many reasons
as possible that the skeleton is important. Also, we’ll ask the kids if they think bones are
alive, and have them name as many bones as possible. We’ll then go over this together.
There are three main purposes the skeleton serves: 1) structure; 2) protection (i.e the
skull or rib cage), and 3) movement, without the ability to anchor to bone, our muscles
couldn’t move us. Also hearing requires bones to work as well. I’ll ask the kids to come
up to the table at this point and show them some real bones that Hilary Mills has on
loan. I’ll then show them what we’ll be doing today, which is going through owl pellets
and finding the bones of rodents, emphasizing that we have a lot of the same types of
bones as other animals. The students will get their materials and begin the actual
lesson.
Part II: Dissecting Owl Pellets (Remainder of time)
Students will work in pairs. Each pair will get one owl pellet, one cardboard sheet, one
bone sorting sheet, one tweezer, one pen and one wooden skewer at the end of the
introduction. There will be one tacky glue bottle/table.
Students dissect the owl pellet together, and use the bone sorting sheet to id the bones
and see how much of a skeleton they can assemble on the cardboard sheet in the time
that we have. Tutors will point out some purposes of the bones and get the kids to think
about where in their body a bone is located.
Vertebrae: Both supporting the weight of the body and protecting the spinal cord. Ask
“Why do you think the spine is in segments?” Point out that the bones are hollow in the
middle. In people the vertebrae get larger as they go down the spine to support more
weight.
Skull: Actually a bunch of bones fused together. Protecting the Brain.
Ribs: Surround and protect the heart, liver, lungs, spleen and kidneys
Sternum: Along with the ribs helps protect the heart, lungs and major blood vessels
from damage
Pelvic Girdle: Connects the spine to the femurs. In childhood each side is 3 separate
bones, which then fuse together. Supports the weight of the body from the vetebrae
column, and protects the lower organs such as the urinary bladder, the reproductive
organs, and also, in pregnant women, the developing fetus.
Bones in the Arm: humerus (aka your funny bone) is the bone in your upper arm, the
ulna and the radius connect to the wrist
Bones in the Leg: femur (the longest, largest and strongest bone in your body); tibia and
fibula (notice that the tibia is larger, it bears the most weight); patella or kneecap
(protects the knee joint)
Shoulder Girdle: Consists of the clavicles and scapulae. Connects the arms to the
central skeletal system (axial skeleton). Also the attachment point for the many
muscles that allow the shoulder and elbow to move.
Cool bone facts to throw out to the kids:
-We have 206 bones in our bodies, but babies are born with 300. Many of these fuse
together to give the adult number.
-Humans and Giraffes have the same number of bones in their necks, the neck
vertebrate in giraffes are just longer
-The longest bone in your body is the femur in your leg (~1/4 of your height, the smallest
is the stirup bone in your ear (1/10 inch)
-97% of animals don’t have a backbone, those that do are pretty similar
-There are 27 bones in your hand, and 14 in your face!
-Every second our bone marrow makes 2 million red blood cells, the marrow is the stuff
in the middle of the bone
-Over a period of seven years the bone is slowly replaced until it is a new bone
-The enamel on your teeth is the strongest substance in your body
-A joint is where two bones meet
-The term skeleton comes from a Greek word meaning “dried up”