Science 4th grade | UNIT 3: Solids‚ liquids and gases 3.6 Melting and boiling points
Every substance melts and boils. Different substances take different times to melt because it takes different amounts of heat to melt them. The amount of heat in a substance is called the temperature.
The temperature at which a substance melts is its melting point. This is when it changes from a solid to a liquid.
The temperature at which a substance boils is its boiling point. This is when it changes from a liquid to a gas.
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Activity 3.6 (Measuring the temperature of water)
You will need: water - a cup - ice cubes - a pan - a hot platea - a thermometer - tongs
Put some water in a cup. Measure the temperature of the water with the thermometer. Record the temperature in °C. This is the temperature of the water at room temperature.
Put the ice cubes in a pan and heat them. As soon as the ice cubes have melted, remove the pan from the hot plate. Take the temperature of the water. Record the temperature. This is the melting point. Now heat the water until it boils. Take the temperature of the steam. Record the temperature. This is the boiling point.
Safety: Be careful of the steam, it can burn you.
Questions
1) What temperatures did you record for:
a: the melting point of water
b: the boiling point of water
c: water at room temperature?
2) Draw a bar chart to show these three temperatures.
3) The melting point of water is 0°C and the boiling point is 100°C.
Did you measure these temperatures? If not, why do you think the temperatures you measured were different?
4) Why should you never put your hand in steam?