The human body is a well-developed
machine that moves efficiently. Ask students how a human moves. The
bones and muscles together make the body move. Both are needed to make
the body walk, run, jump, or preform any other motion that the body is
capable of. If our bones were all one piece, we could not move. The
human body has joints that help movement.
Muscles move the limbs and other
parts of the body in the directions allowed by the ligaments. In the
case of movement at the knee joint, one major muscle is on the front and
several muscles are on the back of the joint. There are similar
arrangements of muscles around the ankles and many other areas of the
body. Bodies are literally a bag of bones that muscles can change into
different figures. All muscles differ from each part of the body.
Motion is all around us. The human
body has developed the forces that act on it, making a human machine
that moves effectively and efficiently. Machines are made to help humans
- Instruct students to touch and move the joints
in their body. Instruct students to do the following:
- Lift their foot about 15 cm off the ground.
Have students rotate their foot.
- Twist their head from left to right.
- Bend their knees.
- Hold their hand in front with palm up. Extend the thumb toward
their pinky then move their thumb straight up.
- Support themselves by leaning on a hand against a table then lift
their foot about 20 cm above the ground. Move the foot so that it
makes a small circle in the air.
- Students have now used their joints. Humans
have many large and small joints. Emphasize that they could not make
graceful movements without joints - they would look like robots.
- Have students feel their muscles by instructing
them to do the following:
- Firmly flex the forearm. Determine the
location on the arm at which a muscle gets tense and enlarges. This is
called the bicep muscles.
- Examine the lower legs while rising up on the toes.
- Clench the teeth together and locate the tense muscles on the face.
- Turn the head to the far left or right. Note where the muscle