Middle and High School … from a Montessori Point of View
The National Snow and Ice Data Center has some interesting data-sets available, including a number of measures of the extent of Arctic sea-ice showing how fast it has been melting.
The Easy-to-use Data Products page has a lot of real data that middle and high school students can use for projects.
This summer’s arctic ice cap is the smallest since we’ve started watching it from space in the 1970’s, and the summer isn’t over yet.
Over the last few years, the rate at which the ice is melting is accelerating, probably due to the ice-albedo feedback. Albedo refers to how reflective a surface is; the average of the Earth is about 31%, while snow and ice has an albedo closer to 90%.
When the albedo is high, a lot of sunlight is reflected back into space, but when it’s lowered, such as when the sea-ice melts, the surface absorbs a lot more sunlight, which heats it up. Of course, more heat melts more ice which further decreases the albedo which causes more warming which melts more ice …. And you can see the problem.
The ice albedo feedback takes a small change (melting ice) and accelerates it. That’s a positive feedback, although the effects are usually not what you want, because they take the system (the Earth’s climate in this case) away from it’s current equilibrium. This is not to say that there are no benefits; the Northwest Passage will open up eventually, if it has not already.
↬ ClimateCentral.org ᔥ the NSIDC
Because the Moon rotates at the same rate as it orbits the Earth:
NASA has an excellent simulation of the complex process of landing Curiosity on Mar. It supplements their awesome 7 Minutes of Terror video.
A quick summary (more details here):
The equation that describes exponential growth is:
Exponential Growth: 
where:
You can set the r value, but that’s a bit abstract so often these models will use the doubling time – the time it takes for the population (the number of cells, or whatever, to double). The doubling time (td) can be calculated from the equation above by:
or if you know the doubling time you can find r using:
Finally, note that the only difference between a growth model and a decay model is the sign on the exponent:
Exponential Decay: 
Decay models have a half-life — the time it takes for half the population to die or change into something else.
Watch brown bears catch salmon in Katmai National Park on a live webcam:
Every year over a hundred Brown Bears descend on a mile long stretch of Brooks River to feast on the largest Sockeye Salmon run in the world.
— bears: brown bear & salmon cam – brooks falls on explore.org
With a simple, but effective interface, ZygoteBODY’s free, online 3d models of human anatomy are excellent.
Anatronica has an excellent, online, 3d viewer for the anatomy of the human torso. While it’s not quite the same as a physical model, it’s pretty good as a study guide for middle schoolers.