discuss possible causes of differences in energy densities between the two materials (wood and charcoal) as well as sources of experimental error

It shows that the experiment is designed properly.

27. =3,500,000 x 4,000 = 14,000,000,000

Those are different gas lawshere is a brief description of themcharles's law states that volume and temperature are directly proportional to each other as long as pressure is held constant.  boyle's law asserts that pressure and volume are inversely proportional to each other at fixed temperature.gay-lussac's law introduces a direct proportionality between temperature and pressure as long as it is at a constant volume.    source:

I'm pretty sure the answer is alcohol