Re: I would like to be able to measure calories and build a calorimeter

Rebecca, 

I think you need information about a food calorimeter,sometimes
known as a bomb calorimeter. I would  advise you NOT to 
attempt to make one yourself.The construction is best left to experts,
and it would be extremely dangerous to try to make one yourself. 
Even the use of bomb calorimeter requires the presence of a qualified 
science teacher.

There is a much safer way to find out the calorific value of nuts:

1. Half-fill a test tube with a known mass of water (in g)
2. Fix the test tube safely in a retort stand
3. Measure the temperature of the water (in degrees C)
4. Measure the mass of the nut (in g)
5. Hold a nut at the end of a long metal pin with a heat-proof
handle.
6. Ignite the nut by placing it in a bunsen flame
7. Place the nut below the test tube until it is completely burnt
8. Record the final temperature of the water.
9. Measure the mass of the remaining burnt nut (in g) 

Do this experiment with supervision from a science teacher.
Precautions are needed. Wear goggles and follow all other 
safety precautions given by your teacher.

The calorific value can be found from 

Calorific value = (mass of water x 4.2 x rise of temperature)
                  _____________________________________________
                     (mass of nut before - mass of burnt nut)

This should give the energy content in Joules per g .

As long as you place the nut close to the bottom of the test tube most
of the heat should go into the water.Of course,there will be some heat 
losses,and this will result in a lower calculated value than the 
value found using professional apparatus.


You can find out more about ready-made professional calorimeters
from the manufacturers. You can find out the different types by looking at Parr Instruments
at http://parrinst.com/bomb_calorimeters.html

Leave the construction to experts...for safety's sake !