As promised in the science birthday tea post I thought I’d share another two of the science makes that the boys did.
First of all – bottle rockets…
These were fairly simple to make – basically use an empty drinks bottle (with a sports cap) add any decorations you like – we glued on craft foam cones and fins and drew on them with permanent marker pens. They all looked quite good…
The next part of the experiment was to fill the bottle a third to half with water, put a hole through the sports cap valve, and then attach it to a foot pump standing between three flower pots. In theory as you pump the air pressure forces the water out and the rocket shoots upwards – sadly these didn’t quite go quite to plan (I couldn’t get a good seal from the pump to the rocket) but the boys enjoyed making them.
Next – Balloon Hovercrafts
First of all you need to drink even more drinks with sports cap bottles (good job the party was on one of the hottest days in May!) and glue the lids onto an old CD (the boys decorated theirs with permanent markers again).
To make them hover – make sure that the valve in the drinks bottle lid is closed, attach a blown up balloon and then pull up the valve and watch your hovercraft float – the boys found that the smoother the floor the faster the hovercraft moved.