Monday 29 December 2014

1.2.1 Laboratory Activity : Scientific Investigation method


Laboratory Activity 1.2.1:
Scientific Investigation method
Aim: Investigating the effect of the temperature of water on the solubility of sugar
Problem statement: Does the amount of sugar that dissolve in water increase when the temperature of water increase?
Hypothesis: The higher the temperature of the water, the greater the mass of sugar that dissolve in it.
Variable:

» Fixed variable : Volume of water and size of sugar

» Manipulated variable : Temperature of water

» Responding variable: Amount of sugar that dissolves at different temperatures
Material:
» Sugar
» Water
Apparatus:
» 100 ml measuring cylinder
» 250 ml beaker
» Electronic balance
» Bunsen burner
» Tripod stand
» Wire gauze
» Spatula
» Thermometer
» Glass rod
Procedures:

The animation below shows the arrangement and the results of the experiment.

1. 100 cm³ of water is measured using a measuring cylinder and is poured into a 250 cm³ beaker.
2. The temperature of the water is recorded using a thermometer.
3. 100 ml beaker is filled with sugar. The beaker and its contents are then weighed and recorded as a gram.
4. The water is added a little at a time to the 100 cm³ of water in the beaker using a spatula. The mixture is then stirred using a glass rod.
5. The process is continued until no sugar can further dissolve in the water.
6. The beaker and its sugar content is weighed again and recorded as b gram.
7. The amount of sugar that dissolved in the water at room temperature is (a - b) gram.
8. The experiment is repeated by heating the water to temperatures of 40 ºC, 50 ºC, 60 ºC and 70 ºC respectively.
Results:

Temperature (ºC) Room temperature 40 50 60 70
Initial mass of beaker and its contents(g) a b c d e
Final mass of beaker and its contents(g) b c d e f
Mass of sugar dissolve(g) a-b b-c c-d d-e d-f

A graph of the mass of sugar dissolved against temperature is plotted.
Conclusion: The amount of sugar that dissolves in the water increases when the temperature of the water increases. The hypothesis is accepted.


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