To determine the melting point of ice - Class 9th Science Lab Work
Experiment - 13
Aim
To determine the melting point of ice.
Theory
The temperature at which a solid changes into its liquid state is known as its melting point. Once a solid attains its melting temperature, the temperature remains same until the entire solid converts into liquid.
Materials Required
Round bottom flask (250 mL), a double bored cork, beaker (100 mL), thermometer (-10ºC − 110ºC), stop-watch (or a stop-clock), spirit lamp(or gas burner), tripod stand with wire gauze, spring balance, a glass tube, a polythene bag, laboratory stand, water, crushed ice, and thread.
Procedure
Step 1: A beaker is taken and filled up to half with crushed ice.
Step 2: Bulb of the thermometer is inserted into the ice and let it stand in a vertical position (Fig. 2).
Step 3: Stop-watch is or the stop-clock switched on and the reading of thermometer is noted and the state of ice in the beaker is observed after every one minute till the whole of ice melts.
Step 4: Recording of the temperature is continued till the temperature of the water so formed rises up to 2−3 ºC.
Observation and Calculations
| Sl. No. | Temp. when ice starts melting in ºC (t1) | Temp. when ice completely melting in ºC (t2) | Boiling point of water (t1+t2)/2 (in ºC) |
| 1 | 0 | 0 | (0+0)/2= 0ºC |
| 2 | 0 | 0 | (0+0)/2 = 0ºC |
Results and Discussion
The melting point of ice is 0ºC.
Precautions
1. The bulb of the thermometer should be completely inside the crushed ice.
2. The thermometer should not touch the wall of the beaker.
3. Recording of temperature and time should be done simultaneously.
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