I was thinking about how there are so many potential applications for
multimedia in the teaching of science and decided to see if I could find an
effective use of multimedia for studying the heart. I found a number, but
really liked this one, which presents multimedia presentations on the brain,
the skeleton, the heart, and the digestive system:

You need shockwave to view this site, and high speed internet. Each screen
has an interactive graphic and a band of text. The text is also narrated. The
site says it would take 20 seconds to load each screen with a 56k modem.
With my high speed internet each screen took from five to seven seconds. It
didn't seem long and it was worth the wait.

The site screen is small, taking up just over a third of my screen, and I
assume it's so that the loading time is kept to a minimum. They are not too
small, though the print is smallish. Older readers may reach for their reading
glasses. (I think it's time I got some!).  The information is chunked
comfortably so that each screen has perhaps five sentences. The content
is certainly suitable for high school, but I would also use it for grade five and
up because the illustrations are excellent, the information is scientific, but
not too difficult for good readers and listeners, and students can listen to
the narration. I was thinking it would be good to use as one of a number of
sites, perhaps as a centre if bandwidth is an issue. Also, students could
listen once, then read and listen, then read... that sort of thing... for
increased comprehension and reading practice.

This site has a number of engaging interactive elements: you can roll the
cursor over the illustrations and detailed, labeled diagrams appear, and
Illustrations are designed to illustrate function. For example, the parts of the
body are superimposed on the skeleton showing how the skeleton supports
them, and an animated heart shows the blood flowing through it and being
oxygenated. You can set the heart rate to fast, normal and slow and watch
the heart pulse. There are also two really cool games: you can try to click
and drag all the bones from a pile on the ground to create a skeleton, and
similarly challenge yourself to put all your digestive organs where they
belong. That's not so easy I have found. Good think it's not a lifeskill
we need to develop in order to survive!