Free Rice

For each question you get right rice is donated to the hungry people in the world.

http://www.freerice.com/index.php

I have added this to this weeks homework.
Change the subject by clicking on the subject tab at the top.
Once you have answered the first question you can change the level. It appears at the bottom.

Breathing Earth
This is incredible! http://www.breathingearth.net/
Hold your mouse over a country to see the population size, births and deaths and CO2 emissions.