Be prepared to make mistakes and try again

We finished off our Young Scientists course by the children planning and carrying out their own investigations. Two groups chose to do ‘balloon-powered’ cars and the other group chose ‘super-sour lemonade’.

I had given them a limited number of themes to choose from and they worked in groups to think about what they wanted to investigate and how they would carry out their experiments. I think this worked well. Last year, each child had a different area of interest or an idea that they wanted to investigate. I had to put in a significant amount of behind-the-scenes work to identify suitable experiments and provide material, and it was hard to cover everything meaningfully.

This year I spent time in weeks leading up to the investigations making sure the children were prepared. I provided forms with prompts such as

Title of investigation


What will happen if my hypothesis is correct?

What might happen if my hypothesis is not correct?

Materials needed




The sixth and seventh classes were entirely dedicated to the children trying out their investigation. I mentioned, both to the children and their parents, that I was not expecting them to get everything right first time. I wanted plenty of time for them to make mistakes, change their ideas or their methods and try things again. I hope that in this way the children learned (by doing, not by being told) that the process of conducting scientific investigations is iterative rather than linear.

Some ‘experiments’ in science courses are designed to back up certain scientific facts or knowledge. They cover the material that the teacher is trying to explain in the course. It can be very helpful to have a visual and hands-on demonstration of these scientific facts. Nevertheless, these are not real experiments. The teachers and children already have an idea of what the ‘right’ result is and they try to adjust their experiments to get that result. Anyone who does not get this result thinks that they have failed and that they are bad at science. I have heard from several of my adult friends that this was the way they felt during science classes.

‘Disappointment’ by Ida Waugh {{PD-US}}

Not so in these classes! I really wanted these experiments to be about the scientific method and not about ‘facts’,or being right or wrong. We did not know how the experiments would turn out. We may have had our suspicions, particularly with the lemonade experiment. The younger children carried out the lemonade experiment and I guided them more than the older groups. For example, I told them how much citric acid and how much water to put into each test bottle. For the other children I provided material and not much else. But all children had plenty of opportunities to try things again and to reflect on the process. For example, both groups making balloon-powered cars found it was really tricky to attach the balloon on to the car and they came up with different solutions to this problem.

In the last class the children presented their investigations in groups, each child or pair of children covering a particular section like background, method, risks, results etc.. I had hoped that all of them could produce a scientific poster for the last session but we used all of the previous classes in conducting the experiments. This was okay. They have had experience presenting material by poster or talks already so we were not focusing on that outcome.

I also provided a folder for each child containing details of the activities they had covered in the course, and some more information about the scientific method and how it works in practice.

I was delighted by how well this course went and I look forward to repeating it with different children who want to find out how scientists work.


Bubbles, craters and taters.

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.

‘Soap bubbles 3’ by Keith Williamson on flickr.

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.)