The importance of ammonia in the formation of salt crystals
The materials required for the science fair project:
- 5 bowls
- 4 sponges
- 1 packet of salt
- 1 bottle of bluing liquid (used in laundry)
- 1 bottle of ammonia
- 1 tablespoon
- 1 caliper
1. For this science fair project, the independent variable is the composition of compounds used in the salt solution. The dependent variable is the amount of salt crystals formed. This is determined through observation and by measuring the height of crystals on the sponge using a caliper. The constants (control variables) are the size of the sponge, the temperature, humidity and air flow of the environment, and the size of the bowls used.
2. Wash, clean and dry the 4 bowls. Then, line up the bowls and label them as ‘Bowl 1’, ‘Bowl 2’, ‘Bowl 3’ and ‘Bowl 4’ respectively. Add the following ingredients to each bowl and mix thoroughly:
a. Bowl 1 – 3 tablespoons of salt and 3 tablespoons of water
b. Bowl 2 - 3 tablespoons of salt, 3 tablespoons of water and 3 tablespoons of bluing liquid
c. Bowl 3 - 3 tablespoons of salt, 3 tablespoons of water, 3 tablespoons of bluing lliquid and 3 tablespoons of ammonia
d. Bowl 4 - 3 tablespoons of salt, 3 tablespoons of water, 3 tablespoons of bluing and 6 tablespoons of ammonia
3. Place a piece of sponge inside each bowl. Leave the bowls in a dry place to allow crystals to form.
4. On the 3rd day, prepare 4 more bowls of solution as mentioned in step 2. Add more liquid to each bowl, taking care not to drip the solution onto the growing crystals.
5. Allow the crystal to grow for a total of 10 days and record your observations in a table, as shown below. Measure the height of the crystals on the sponge with a caliper.
Handle the ammonia carefully.