Our third class in this year’s Young Scientists course saw the children discussing the slime experiment from last week and then going on to measure the height of foam created when you do the dishwashing. I wanted them to understand about all the variables that can affect a result. Many scientific experiments are based on isolating and changing just one (independent) variable, while holding all the others constant, to see what happened to the dependent variable, or the thing we were measuring.
I always ask the children to assess risks before they carry out experiments and to assess how the experiment went, after they have performed it. It’s interesting to hear the ideas they come up with. We are not doing any quantitative risk assessment but I am trying to get them to think about the likelihood of some of the events happening.
The children then had a go at planning an experiment for the next class. Most children chose to do an experiment investigating how much water is in a potato. See the second video in the Open University series here. (This experiment also features in online the Open University course ‘Understanding Experiments’ which is completely free and available on the Open Learn website.)
A few children wanted to investigate crater formation. I’ve linked to the Science Buddies instructions but we did a variation of this experiment last year in the Earth and Space Science course and it was popular.
I asked them to think about what they were investigating, the variables involved, their hypothesis and what materials they wanted to use.
We also started to discuss what experiments the children wanted to carry out in the second half of the course. I have allowed two full classes for trying out their experiments and I want the older children especially to take charge, rather than letting me tell them what to do.
In Class 4 we carried out the potato experiment and the craters experiment. The children enjoyed these experiments, especially when the potato burst on fire! (This had been predicted and planned for and we controlled the fire very successfully.)