In 5th class our theme for the science fair was the environment. We explored how we could use the energy of the sun (solar energy) in different ways. Before the science fair we did an experiment with our student teacher, Ms Carroll, where we placed containers of water (that were sealed with clingfilm) in direct sunlight and out of direct sunlight and examined the difference in temperature between the two. Although it wasn’t a large difference, after a few hours we found that the water in the container in direct sun was a couple of degrees warmer than the water in the container out of direct sun.
From here we looked at how we could use solar energy to help us complete an every day task. We found out that people sometimes use solar ovens to cook food, especially when there isn’t access to electricity e.g. when camping or in places that aren’t connected to electricity. It is possible to buy solar ovens but where’s the fun in that!? We decided to make our own!
We used pizza boxes as the structure for our ovens. We lined the it with black paper (because black absorbs the heat) and tinfoil (because it reflects the sunlight). We had clear plastic ready to seal our ovens and trap the heat once we had decided what we wanted to cook.
We discussed what food to make – some people suggested sausages and other meats, which we decided against as we didn’t want to give anyone food poisoning from under cooked meats! In the end we picked meringues because they will cook at a low temperature and we didn’t know how hot our ovens would get.
Once we’d made our meringue mixture we put them into our ovens and sealed them. We placed them in a sunny place in our classroom but after lunch we had to move them to the end of the corridor in order to catch the afternoon rays.
We found it took a good while for the meringues to cook (a few days) and the weather didn’t always co-operate! A solar oven requires solar energy from the sun. However, it being Ireland, there are a lot of cloudy days which means the sun’s rays weren’t hitting the box. We also talked about how the sun’s rays aren’t as strong in Ireland as they are in places closer to the equator. We decided that this experiment would worked better in place further south with more constant sunshine e.g. Spain.
You might have spotted some of our class on RTÉ 2 a few days after the science fair explaining to reporters about our project!