After making sure the temperature is 75 degrees then quickly cover it up with foil even the top of the beaker and then start the stop clock. Then you have to measure the temperature in the beaker every two minutes until it goes to 10 minutes. Do this same procedure for cotton wool, bubble rap and black paper. If you’ve done all of this then do one with no insulation.
Conclusion
My results told me that cotton wool is the best insulator out of the other materials. Now I know why because I went and got some more information about heat loss. Cotton wool is the best insulator because the wool doesn’t allow convection or radiation to happen. The only way the heat could escape was through conduction and only a small amount of heat was lost by conduction because the particles go from the hot side to the cold side but this process is very slow. Foil was the second best insulator because the shiny surface reflected the heat back by radiation but most of the heat was lost by conduction and foil is quiet a good conductor. Then it was bubble rap and black paper. Bubble rap had some air between the plastic so the heat was lost by conduction then convection. Black paper came last because its dull and black surface absorbed the heat then lost by convection in to the air outside.
I noticed in my results that for cotton wool and foil the temperature only went down 1 or 2 degrees every two minutes but for bubble rap and black paper it lost 5 or 6 degrees each time.
As you can see my prediction wasn’t really correct according to my results because of cotton wool, I thought that its going to loose heat by the hot air going through it, but the air cant just travel through it because it’s a solid.
Heat Transfer
Heat energy causes molecules in gases and liquid to move around faster and the particles in solids to vibrate. When the particles move faster the temperature tends to rise. When the temperature had risen the heat goes from a hot surrounding to a cooler surrounding.
There are 3 main ways heat can travel by conduction, convection and radiation.
Conduction
Conduction occurs mainly in solids. Thus is the process where vibrating particles pass on their extra vibration energy to the nearby particles. This process goes on through out the solid until it causes a rise in temperature at the other side.
The heat that is usually transferred by conduction is very slow if convection can’t t happen on the material another words if it’s a solid.
Convection
Only occurs in gases and liquids because the particles are free to move about it can’t happen in solids because the particles don’t move. Convection happens when more energetic particles move from the hotter region to the cooler region and take their energy with them. When the more energetic (i.e. hotter) particles get somewhere cooler they then transfer their energy by collision, which warms up the surroundings. An example of this can be the wind.
Radiation
Also known as infrared radiation and it entirely consists of electromagnetic waves, it travels in straight lines at the speed of light, it can be reflected back by a silver surface and it can be absorbed by dark matt surfaces. It goes through transparent materials e.g. water or glass and no particles are involved. The hotter they are the more radiant heat it gives out. Cooler ones around them will absorb this heat. You can feel this by standing near a fire.
Evaluation
I think I did a kind of a fair test because I kept the starting temperature the same for all the different materials. My results were not that accurate even though I did the experiment three times, I still got some different results that were kind of odd by a small number of degrees. This is what made me think hard for my average results. This is because I didn’t look at the thermometer properly it might have couple of degrees short or higher.
Something that really contributed in my results was the room temperature because I did the experiment in a period f two days. The temperature might have been lower in the second day and that might have caused the temperature in the beaker to come down quicker. Next time I will hopefully try to finish the experiment in one day. When I did my experiment I covered the whole beaker with the material to make a fair test, but I didn’t cover the bottom of the beaker. I know that heat rises but their still could be some heat lost from the bottom of the beaker.
I think my results were not enough to make a firm conclusion because the first try of the experiment was very inaccurate so my average results didn’t come out very accurate.
I can extend my work by taking the temperature every one-minute and doing that for a longer period of time. I can also try out different materials or even possibly doing a combination of two different materials together.
