OBJECTIVE

In this experiment, you will find the specific heat of a metal by using the method of mixtures.

THEORY

The heat necessary to raise the temperature of a material of $1$ kg by $1$C is called the specific heat

capacity or the specific heat of a substance. For example, if you have two objects of equal mass

$($e$.$g$.,$ two cubes, one of iron and one of wood$)$ and you wish to raise their temperatures from $27$ to

$28$ degrees C$,$ then the amount of heat each object needs in order to raise their temperature by $1$

degree $(2827=1$C$)$ will be different. So specific heat is the heat necessary to raise the

temperature of each object by $1$ degree. Mathematically, we say that the amount of heat added, Q$,$

to a substance is proportional to the change in temperature, or

$=(1)$

where m is the mass of the substance and c is the specific heat.

Units:

The traditional unit of heat is the calorie $($cal$),$ which is the amount of heat necessary to raise the

temperature of $1$ gram of water by $1$C$.$ The unit of specific heat that we will use is cal$/$g$.$oC$.$ Read

this brief introduction to Specific Heat.

THE METHOD OF MIXTURES

We are interested in making an experiment to find the specific heat of a metal by using the

method of mixtures. The method basically states that if different substances at various

temperatures are mixed together, the hotter ones will lose heat and the colder ones will gain heat.

This process of heat transfer, from hotter to colder, will continue until all the substances involved

reach a common equilibrium temperature. In addition, the conservation of energy law states that

if a system is kept insulated from its surroundings so that no heat can enter or leave the system

then the amount of heat lost is equal to the amount of heat gained. That is$,$

Heat Lost $=$ Heat Gained $(2$a$)$

That is

$=(2)$

We will come back to this important equation in a moment.

Experimental Procedure

Tools Needed:

$$ A thermal coffee cup with a lid. The lid has a hole $($for the straw$).$ We will use the hole to

insert a thermometer. If a thermal coffee cup is not available, a small$-$size Styrofoam cup

with a plastic lid should be fine.

$$ Hot plate $($stove top$)$ or any heating device.