Our Cubs are working towards their Scientist badge, and this week they took on three very hands on experiments, with varying degrees of success.
The first experiment was to prove whether or not a substance can be both a solid and a liquid, without changing the temperature. The cubs mixed cornflour with water and a little food colouring and ran their fingers through it. They noticed that as they stirred it around it was very fluid. Trying to pick it up it ran through their fingers, but if they spooned it into their hand, they could roll it into a ball. As soon as they stopped rolling, it turned back into a liquid so they could pour it back into the bowl. If they punched the liquid in the bowl it behaved like a solid and you couldn’t break the surface! We’ll be trying out a few more experiments with this gloop next week and understanding why this happens.
Next they made compasses. By stroking along a needle with a magnet (always in the same direction), the Cubs magnetised the needle. Filling a bowl with water, they then placed a small flat piece of cork on the surface and laid the needle on top of the cork. The needle spun around to face north. This was checked by a real compass and found to be remarkable accurate!
Finally, the Cubs looked at chemical reactions, by pouring vinegar over wire wool in a jar. The expectation was that the protective coating on the wire wool would be removed by the vinegar, then the iron in the steel should react with the oxygen in the air and would form rust. This in turn should cause an exothermic reaction (generate heat) but in the time allowed and the limitations of the thermometers used they were unable to prove this, so will try again next week with more sensitive thermometers and allowing a longer time frame.
Next week we will be looking at how pulse rates are affected by exercise and trying a couple more experiments before the Cubs complete their Scientist badge, but suffice to say that they will have a blast on the journey!
