I like to move it, move it!
All of the activities this week involve making something, but all of them should also allow you a chance to explore ideas about forces and movement once you have finished.
To kick off, this balloon hovercraft will allow you to explore friction (the parachute activity from a couple of weeks ago is good for exploring air resistance). This one uses superglue, but I've successfully made one using blue tack to join the top to the CD.
We made some Pringles tube cannons (other brands are available) as seen in the video by the RI for the Pirate themed Spring Brunch a few years ago. If you find all your rubber bands are a bit short, then chaining them together works well for this. In the video, there are lots of suggested experiments and investigations that you can do once you've built it. For an even simpler hand cannon this cup launcher works well too. Both of these are good for talking about energy transfers (the stored energy created when you stretch the balloon or rubber band being converted to kinetic energy to fire the balls).
The crafts council has a nice set of instructions for building simple automata using cardboard cams and is good for looking at simple mechanical systems. On the other hand, if you fancy building more complicated contraptions involving dominoes, marble runs, pendulums etc there's a selection of ideas here from the Exploratorium on building your own chain reaction machine (there are loads of example machines on you tube if you search for Rube Goldberg or Heath Robinson machines).
Some of you may remember making cotton reel cars when you were young. This video from the Women's Engineering Society shows how to make one and talks about the science. I have seen them made with other cylindrical objects as well if you can't lay your hands on a cotton reel. I do have some spare cotton reels at home - email me if you'd like me to post you a couple.
Why not have a go at building this gravity defying tin that rolls uphill and challenge other people to figure out how it works (without looking inside the tin!). I've not usually needed the rubber coating that Matt has added when I've made one but you may need to try different angles for your slopes to stop it sliding (rather than rolling). While looking for a good website that showed you how to make this, I came across this rather splendid optical illusion.
Another seemingly gravity defying object is this climbing frog which uses friction to climb up two strings and for another moving frog, have a go at folding the origami frog shown above that can be made to jump.
For some straightforward silliness, this old school flapping fish race game takes some beating although it works best in a large indoor space or outside on a still day.
And finally ...
Another book recommendation, Mr Shaha's Recipes for wonder which is a book with lots of simple experiments that you can do together with your children alongside some suggestions for scientific ideas to investigate together. You can see him demonstrating some of the ideas in this video (that includes several of the activities above).
The Dyson Foundation has created a set of challenge cards with lots of different ideas and are well worth a look.