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.

» Fixed variable : Volume of water and size of sugar

» Manipulated variable : Temperature of water

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

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.

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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