Hunkin's Experiments has some cool science acitivites aimed at primary school age students.

"Cool cartoons that will have you experimenting with food, light, sound, clothes, and a whole lot more!! Hundreds of cartoon experiments from cartoonist, broadcaster and engineer Tim Hunkin."

My personal fave: How to make a camera out of a baked bean tin

Australia's Commonwealth Scientific Industrial Research Organisation (CSIRO) Science by Email is a weekly email newsletter featuring science news and activities.

Science by Email delivers the world's best science direct to your inbox. It contains:

• the latest science news
• fun activities and experiments
• environmental insights
• a quiz
• SCOPE TV previews
• the best science websites
• occasional competitions
• upcoming events.

Another science site for kids is Toys from Trash