Comparing sizes in the solar system

Just to prove that I wouldn't pass an exclusively science site by, I wanted to let everyone know about a website that allows students to compare sizes of the eight planets (R.I.P. Pluto) and much, much more.

Embed your Powerpoints

I just signed up for a free service called authorSTREAM, which I found by way of Larry Ferlazzo's ESL blog. authorSTREAM allows you to upload Powerpoint Presentations (with sound if you like) to be viewed on their site or embedded in your own blog or website. I was thinking of a blog that had each Powerpoint that had been shown to the students right there to be accessed at any time.