Heat Loss In Coffee Essay, Research Paper

Prediction I predict that the best way to keep coffee warm is to have a

silver insulator because of what we know on radiation and silver being a poor

emitter compared to a plain beaker or a black one. I predicted this because

most saucepans are silver because silver is a poor emitter compared to white

and black and also silver? is shiny

which cuts down heat wasted by radiation.Research? ??After making a cup of coffee it loses heat because of the

following factor:·

Radiation ·

Evaporation ·

Conduction ·

ConvectionRadiation The sun radiates heat through

empty space in the form of tiny waves. If you absorb any of the Sun?s

radiation, it heats you up. This is why it is sometimes called Heat radiation.

Everything gives off some heat radiation. The hotter it is the more it

radiates. A black area absorbs much more radiation than a white surface. Much

of the radiation that hits a white surface reflects away. A silver surface is a

poor absorber and good reflector. An example of radiation is a saucepan. (A

saucepan loses heat with radiation and conduction. Also it loses heat by

convection by air currents rising above the saucepan.)Evaporation Evaporation works in a similar way to conduction. When the

beaker or water is heated the molecules vibrate more at different speeds. Every

so often, one molecule will gain a lot more speed than the others and will

escape. When it finally escapes it all it?s energy with it so less is left

behind. Now that there is less energy they are cooler. Conduction This is the only method of heat transfer that happens in

opaque solids. In the solid the particles are fixed. When heat is added they

start to vibrate one by one banging into their neighbouring particle. This is

how heat energy is passed on from one particle to the next. Good conductors are

metals such as gold, silver and glass. A glass beaker can be safety heated on a

gauze because a gauze conducts heat away from a flame. ConvectionThis method of heat transfer mainly occurs in liquid and

gas. In our experiment the water lost heat by convection because the hot water

at the bottom density decrease so it rose to the top and cooled. The slightly

cooler water descended towards the bottom creating a circulatory motion Variables To make the experiment a fair test the starting temperature

was kept to as near as possible. We did not change the amount of water used so

it would be fair. ?Same Vary Amount of water Insulator Size beaker Safety To make sure that this experiment was safe we were careful

pouring the hot water by holding the measuring cylinder with a cloth. ObservationsIn this experiment we will be taking the temperature every

one minute up to ten minutes. To make this a fair and accurate test we will be

repeating the experiment again. Apparatus ·

3C

beaker size 250ml ·

Thermometer ·

Silver foil ·

Black paper ·

Kettle ·

Sellotape ·

Scissors To Test for Radiation ??????????????????????????????????????????????????????????????????????? Wrap the

beaker in silver foil and black paper and plain and see what is the best

insulator.See what dye

is the best yellow or black Method . Set

up apparatus as shown with a thermometer inside it.. Heat

up the water and pour into the beaker..

Quickly take the temperature every minute up to ten minutes and record in the

results.Results Table for insulators Minutes Black 1 Silver 1 Plain 1 Black 2 Silver 2 Plain 2 Black 3 Silver 3 Plain 3 0 85 86 85 84 83 82 75 78 73 1 73 75 72 72 74 73 70 71 71 2 70 73 69 70 72 71 68 69 68 3 68 71 67 67 70 62 66 67 66 4 65 68 66 65 67 61 65 65 63 5 64 67 63 64 66 60 63 64 61 6 62 66 61 62 64 60 62 63 59 7 61 64 59 61 63 59 60 61 59 8 60 62 58 58 61 57 59 60 58 9 59 61 57 58 60 55 58 59 56 10 58 60 55 57 58 54 57 58 53 Result table for dye Minutes Yellow Dye 1 Black Dye 1 Yellow Dye 2 Black Dye 2 0 82 85 75 74 1 77 74 68 64 2 74 71 67 63 3 71 68 65 61 4 69 66 64 60 5 67 64 62 59 6 66 62 61 57 7 64 60 59 55 8 63 59 57.5 54 9 62 57 56 52 10 60 56 55 52 The starting temperatures are starting at different

temperatures, which make the graph unfair. So I need to work out the

temperature change so I can plot an accurate graph. Minutes Average Black Average Change In Black Average Plain Average Change In Plain Average Silver Average Change In Silver 0 81 0 80 0 82 0 1 72 9 72 9 73 9 2 69 12 70 10 71 11 3 67 14 65 15 69 13 4 65 16 63 17 67 15 5 64 17 61 19 66 16 6 62 19 60 20 64 18 7 61 20 59 21 63 19 8 59 22 58 22 61 21 9 58 23 56 24 60 22 10 57 24 54 26 59 23 Minutes Average Yellow Dye Average Change In Yellow Dye Average Black Dye Average Change In Black Dye 0 79 0 80 0 1 73 6 69 11 2 71 8 67 13 3 68 11 65 15 4 67 12 63 17 5 65 14 62 18 6 64 15 60 20 7 62 17 58 22 8 60 19 57 23 9 59 20 55 25 10 58 21 54 26 Conclusion My prediction was right silver is the best insulator. I know

this because at ten minutes silver has not had such a big temperature change

compared to the others. We know that heat is being lost because of the graph

temperature change is increasing as the time is increasing.EvaluationI think that during this experiment we use our apparatus

accurately by having the same size beaker and measuring cylinder. I think that

our experiment wasn?t extremely accurate because of the cooling down at the

start. This caused different starting temperature but because the table and

graph recorded the change it didn?t affect too much. ??????????? In my graph

it shows that Silver is the best followed by black and plain last. On the other

further experiment it showed that yellow dye was better than black dye. I

thought that my experiment went well but that human error must have been caused

because it was difficult at one time because of measuring and recording all of

them at the same time this showed in my plain line where the circled point

didn?t fit in.