When building calorimeters, a material with a low specific heat is often used (such as Styrofoam, aluminum, etc.). Differences in temperature cause heat transfer, so a larger difference in temperature between the calorimeter and the surrounding air would mean more heat transfer from the calorimeter to the surroundings.

Hence the heating effect produced by an electric current, I through a conductor of resistance, R for a time, t is given by H = I2Rt. This equation is called the Joule’s equation of electrical heating.

pyrometers

Calorimeter, device for measuring the heat developed during a mechanical, electrical, or chemical reaction, and for calculating the heat capacity of materials.

Buying a calorimeter is an investment, so you need to have confidence in your supplier.

A coffee cup calorimeter is a constant pressure calorimeter. As such, the heat that is measured in such a device is equivalent to the change in enthalpy. A coffee cup calorimeter is typically used for solution based chemistry and as such generally involves a reaction with little or no volume change.

The biggest source of error in calorimetry is usually unwanted heat loss to the surroundings.

A coffee cup calorimeter is great for measuring heat flow in a chemical solution, but it can’t be used for reactions, which involve gases since they would escape from the cup. A bomb calorimeter is used to measure heat flow for solids with low to high temperature reactions.

The role of the Styrofoam in a coffee cup calorimeter is that it reduces the amount of heat exchange between the water in the coffee cup and the surrounding air. The value of a lid on the coffee cup is that it also reduces the amount of heat exchange between the water and the surrounding air.