The air cell increases in size during incubation at a rate that depends on temperature and humidity as moisture evaporates from the egg. The drawing shows the normal size of an egg's air cell at 7, 14, and 18 days of incubation. Size of the air cell in the egg on the 7th, 14th, and 18th day of incubation.
A specific heat capacity is the amount of energy necessary to increase the temperature of a kilogram of that substance by one kelvin. Molar heat capacity is the amount of energy necessary to raise one mole of substance by one kelvin degree. One mole of a substance is exactly 6.02x10 23 atoms or molecules of that substance.
Avogadro's number tells us there are 6.022 x 1023 molecules of water per mole of water. So, next we calculate how many molecules there are in a drop of water, which we determined contains 0.002775 moles: molecules in a drop of water = (6.022 x 1023 molecules/mole) x 0.002275 moles.