There's a mini-science museum called Discovery in the Brewers Quay in Weymouth and it's great. it's three smallish rooms choca with physics stuff you can play with ! esther and i went and it we had the place to ourselves.

esther loved the mirrors best - there was a room where you could go in and shut the door and see yourself off to infinity in all directions.

and i always love a fish eye mirror

highly recommended !