I had been meaning to do the Thermal Conduction Experiment with Spoons with my children but just hadn’t got around to it. So when I was sent a pair of Heat Holders Thermal socks and questions were raised about them, it seemed the perfect time to explain about thermal conduction and thermal insulation.
About Heat Holders Thermal socks
With a Tog rating of 2.3, making them over seven times warmer than a basic cotton sock, they are the ultimate thermal sock. Heat holders advanced construction holds more warm air close to the skin, keeping feet warmer for longer! They have advanced insulating yarn, long looped thermal pile and soft brushed inners.
My verdict: They were indeed really good at keeping the heat in and really comfortable. The purple colour I was afraid might run in the wash but not a drop. I would recommend them.
Insulators of heat
My son was surprised to learn that thermal clothing did not heat the body up, but that actually they worked by not letting the heat escape. We talked about the other insulators of heat. The first things that were mentioned were different types of thermal clothing – hats, vests, pyjamas. Then we went on to think about other things around our home: Things such as oven gloves, thermos flasks, and the plastic kettle. We decided that plastic, cork and fabrics were good thermal insulators. We talked about how some thermal insulators are used to keep the heat out as well as in – such as a cool box. That what we mean by a good thermal insulator is that it is a bad conductor of heat.
The Spoon Conducting heat experiment
This is probably the lesson I remember most at school, mainly because to this day it is one that I put into practise most days in the kitchen. It is about which materials are good conductors of heat, and which ones are good insulators of heat.
What is the Problem?
The Problem is we want to know which materials are good conductors of heat, and which are good insulators of heat?
The independent variables (something that is changed in the experiment) were the types of material the spoons were made from – wood, plastic and metal. The dependent variables (what you are measuring in the experiment) were whether the handles were hot or cold. The constant variables were the container the spoons and water were placed in, the level and type of liquid, the times the spoons were checked. For a controlled variable we had spoons of the same materials not in the water to determine whether they would change temperature over time without added heat.
We considered what we had learnt about the different materials around the home before drawing our own hypothesis. I may have had a helping hand in talking about irons and the metal plate to encourage them to come to the conclusion that the metal would be the one that would get hurt, as I didn’t want them to touch it for too long and burn themselves (although they shouldn’t I would still prefer them to be aware of it getting hot and be cautious).
We hypothesized that the metal spoon would get hot the quickest.
Saucepan of water
Spoons – 2 of each metal, wood, and plastic.
Sheet to record results.
The water in the pan is heated enough to be considered hot (but not boiling). One of each of the types of spoon were left on the side, and one of each type gently placed in the water (making sure they are not touching). After 1 minute each of the spoons were tested by someone to determine whether they were hot, and the result recorded. This was repeated after 5 minutes, and 10 minutes. If at any point the spoon was hot it did not need touching again.
Results & Conclusion
The results did show that the metal spoon was the only one to get hot. In conclusion we said that metal was a good conductor of heat, and that wood and plastic were good insulators of heat.
We talked about how it was a fair test because the spoons are roughly all the same size and shape, but that actually they weren’t complete and that the spoons left on the side had all remained cold so we do not think that any differences had affected our results. Another experiment could look at whether size makes the spoon heat up faster.
A difference could be due to different testers deciding whether the spoon was hot or not. This could be changed by one person testing the spoons but then confounding results may come from the transference of heat from their hands. The spoons all being in the water at the same time may have affected the conductivity of each other if they had touched one another, but to do it separately may have caused slight differences in the temperature of the water.
This experiment is really useful for everyday life in determining which spoon is best for different types of cooking, serving up and eating. As I have mentioned it is Science Engineering week, and part of their job is to define the problem and consider the constraints involved. For them knowledge of good conductors and insulators of heat are very important so that they know which is the best material for the job at hand. They also do not want to put anyone being at risk of being burnt!
In summary we learnt that heat only moves from hot things to cold things. Some things let heat travel through them easily and are called thermal conductors. Other things do not let heat pass through them and are called thermal insulators. Thermal insulators can help keep things hot or cold.
I received a free pair of Heat Holders socks in order to review them. All opinions are my own.