Science Interactives and Apps

Crickweb have many good interactive games and animations.
BBC Science Clips 
These are interactive simulations that can be used with a whole class on a whiteboard or at individual computers.
The activities are organised by year groups 1 to 6 and are based on the QCA scheme of work.

Sheppard Software
Many beautifully presented interactives including health and nutrition on their website here.
Particularly good are the animal, plant and environment games and animations at their Kid's Corner here

Teaching Appz
Teaching Appz
This is one of Mark Warner's great free sites.