Dissolving tablets more quickly
The materials required for this science fair project:
- 8 Alka-Seltzer tablets
- 8 beakers
- 1 large beaker
- 1 bottle of ice water
- 1 pack of ice cubes
- 800ml of Hydrochloric acid at pH 2
- 1 hot plate
- 1 thermometer
- pH paper
- 1 measuring cylinder
- 1 stopwatch
1. For this science project, the independent variable is whether water or hydrochloric acid is used as the solution, and the temperature of the solution. The dependent variable is the time taken by the Alka-Seltzer tablet to fully dissolve in the solution. This is determined using a stopwatch. The constants (control variables) are the amount of water used, the size of the tablet and the air pressure in the room.
2. The first beaker is filled with 200ml of ice water. Water and ice cubes are added to bring the temperature to 15°C, and the volume of the water is adjusted back to 200ml. 1 Alka-Seltzer tablet is placed in the water and the time taken for the tablet to fully dissolve is checked using the stopwatch and recorded in the table given below.
3. Using another 3 beakers filled with 200ml water and the hot plate, the temperature of the water is brought to 25°C, 35°C and 45°C. One Alka-Seltzer tablet is placed in each beaker and the time taken for the tablet to dissolve is measured and recorded in the table below.
4. The remaining 4 beakers are filled with hydrochloric acid. The temperature of the first beaker is brought to 15°C as explained in procedure 2 and the time for the Alka-Seltzer tablet to dissolve is measured and recorded in the table below.
5. The temperature of the remaining 3 beakers filled with hydrochloric acid are brought to 25°C, 35°C and 45°C using the hot plate and the time required for the Alka-Seltzer tablet to dissolve is measured and recorded in the table below
Basic safety requirements