"Boiling point of Water" Return to list of pracs

Aim: This activity is used to investigate the boiling point of water..

Equipment: The equipment includes...  

• pot;
• water;
• thermometer;
• stopwatch.

Method: Place approximately 2 cups of water in a pot and place it on an oven with a low heat. Record the temperature using a thermometer every minute for 15 minutes. Note the change in temperature values and particularly the change in temperature as it approaches 100 degrees Celsius. Draw a line graph of temperature versus time.

Background knowledge: Heat applied to ice will melt it. Normally the addition of heat raises the temperature of the water. The temperature will actually not rise until all of the ice molecules have been converted into water. It is only then that the temperature will begin to rise again. The water will stay at 100 oC until all of the water molecules have changed to steam molecules before the temperature increases again. Note the rate of temperature change as it approaches 100 degrees Celcius levels off ...

Another thing is that temperature is related to internal energy of a system. It is related to the average amount of movement energy of the water. So, anything that increases the amount of movement should increase the temperature. For example, hammering a piece of metal; rubbing your hands together; heating metal in a fire; pumping a bike tyre. Matter exists as a solid, liquid or gas.