See how the human heart moves blood through the body in this animated feature from the NOVA: "Cut to the Heart" Web site.

If you have ever had to adjust to a new time zone, you have noticed that it takes a while before you start to feel normal again. By shifting your sleep and activity schedule, you have altered the pattern of your body's circadian rhythms....

After exercise, your heart rate increases, this is normal for everyone. However this experiment asks whether the recovery time for a heart's beating rate is faster for people who get regular exercise versus those that do not.

Heart rates can be determined by the amount of physical activity your body is engaging in. The more physically active you are, the faster your heart beats. You can measure the rate your heart is beating by taking your pulse. This science...

Self-guided learning activity where students learn about the structure and function of the human cardiovascular system. There is a short quiz at the end of the lesson to check for understanding.

This feature from the NOVA: "Cut to the Heart" highlights facts about the heart, including its size and placement, and will help you to understand the importance of this wondrous organ in our bodies.

This interactive site provides animations and activities in several areas of physiology. The images are simple, but clear. The accompanying text provides a good description of the process being shown.

In this lesson plan students will use water balloons to simulate the effects of gravity and microgravity on fluid distribution in the body.