Lab 21.1

Thermal Energy of a Peanut

Abstract:

We measured the amount of energy given off into water from a burning peanut and likewise from a burning marshmallow.

We found that the average for 4 pairs of change in temperature in a burning marshmallow was 8.3 degrees Celsius.

We found that the average kcal per gm. for the class "peanut" data was 0.803 kcal/gm.

Data:

?(see sheets)

Calculations:

Ti - Tf = /T

22.7celcius - 36.5celcius = /T

-13.8 Celsius = /T

m'mallow % error:

%error = theo. - exp.

theo.

%error = 6.00kcal/gm - .742kcal/gm * 100

6.00kcal/gm

%error = 88%

Peanut % error:

%error = theo. - exp.

theo.

%error = 3.25kcal/gm - .0083kcal/gm * 100

3.25kcal/gm

%error = 99%

Q=MC/T (peanut)

Q=(20gm)(1.00cal/gm°C)(41.9°C)

Q=838c

Graph:

?(see sheet)

Questions:

1.The percent error was 88%.

this is most likely due to the inaccuracies in or data taking. These reasons will be addressed in question # 4.

2.The percent error was 99%

Indicating that the experiment had many flaws, these various sources of error are expanded on in questions #3 and #4

3. It may have gone in to any combination of the following:

The air around it, the glass test tube, the metal holder and even into the person themselves (through the holder), the needle which it was on,into the cork and thus even into the table. It may have also turned into smoke and gone into the air.

4. The main things that could have effected the peanut results were:

the problems addressed in # 3, in some cases relighting the peanut,

a bad flame(burn),and not having the test-tube close enough to the peanut.

5.The peanut: it is a more concentrated material.

6.Again the peanut, and again because in is a much more concentrated material. One proof of this is in the total burn time (duration of the flame)

peanut: 243 sec. the mallow: 17.3 sec.

7.yes, we (i) did get a fairly straight line(see graph). However I dont think the class data would follow close to my graphs pattern: the range in difference was large in most areas. For example: final temp,group #5: 25.3 cel.

Final temp, group #2: 65.7 cel.

8. the slope: M=0.25 cel/sec

I would expect a steeper slope for the marshmallow, because the marshmallow burned at a much faster pase then the peanut.

My groups data proves this: In only 17.3 sec (total burn time) the heat went up from its initial temp. of 22.3 cel. to 30.5 cel. (8.2 degrees of change.) It took the peanut a full 30 sec. just to heat up 0.3 degrees

(22.7 cel. to 23.0 cel.).

This all shows that the mallow has a lower specific heat than the peanut.

9.(See sheet)

Conclusion:

We attempted to find the amount of energy given off from a peanut/

marshmallow into water.We found that the peanut gave off more energy.

We also found the amount of thermal energy contained by both a peanut and a marshmallow. Thus we found that the marshmallow has a lower specific heat than the peanut. The Proof: (As stated in question #8)

In only 17.3 sec (total burn time) the heat went up from its initial temp. of 22.3 cel. to 30.5 cel. (8.2 degrees of change.) It took the peanut a full 30 sec. just to heat up 0.3 degrees (22.7 cel. to 23.0 cel.)

With the percent errors being 88% and 99%,respectively, the experiment

can can be much improved from the problems explained in questions #3 and #4. The ways of improvement in this experiment are the following: conducting the experiment in a sealed off device (calorimeter). Another way would be to somehow get all the energy emitted from the peanut or mallow directly into the test tube/water. A third way would be to avoid all outside heat influences (again,isolation). If you do not have the necessary tools several simple suggestions are the following: seal the test-tube, make sure the test-tube is constantly right in the flame, and in a more controlled environment.