Effect of temperature on solubility
The materials required for this science fair project:
- 3 beakers
- 300ml water
- Some ice cubes
- 1 measuring cylinder
- 1 hot plate
- 1 thermometer
- 1 kg sugar
- 100 grams salt
- 100 grams sodium bicarbonate
- 1 digital weighing scale
- 1 spatula
1. For this experiment, the independent variable is the temperature of the solvent (water) and the type of substance used – sugar, salt and sodium bicarbonate. The dependent variable is the amount of substance dissolved in the water. This is determined by measuring the weight of the substance using the digital weighing scale. The constants (control variables) are the type of solvent (water), the amount of water used and the air pressure in the room.
2. The 3 beakers are labeled as “sugar”, “salt” and “sodium bicarbonate”.
3. The temperature of the water is brought to 20°C by adding some ice cubes to the water. Once the temperature of the water has stabilized, 100ml of the water is measured using the measurement cylinder and poured into each of the 3 beakers.
4. Sugar is added, 10 mg at a time, to the beaker labeled “sugar” and it is mixed using the spatula. The sugar is continuously added until it is not able to dissolve in the water anymore. The amount of sugar that has been added is calculated and recorded in the table given below.
5. The beaker is now placed on the hot plate and the temperature of the solution is brought to 40°C. The sugar is again added, 10mg a time, until it does not dissolve in the water anymore. The total sugar added (including the sugar previously added) is calculated and recorded in the table below.
6. Step 5 is again repeated at 60°C, 80°C and 100°C and the results are recorded in the table below.
7. Steps 4, 5 and 6 are again repeated using salt and sodium bicarbonate. However these 2 substances will be added to the water 1mg a time instead of the 10mg used for sugar. The results are recorded in the table below.