Page 26 - Ranger SPM 2022 - Science

Science SPM Chapter 10 Chemicals in Medicine and Health
5. The following describes an experiment on oxidation.

Aim: Apparatus:
To study the effect of different solutions on Knife, Petri dish, beakers, forceps
the oxidation of apples.
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Procedure:
Problem statement: 1. An apple was cut into 5 equal slices.
How do we slow down the oxidation of A slice was placed in a Petri dish as
apples? a control.
2. The other four apple slices were
Hypothesis: immersed in the following solutions
A solution which contains an antioxidant for 15 minutes:
slows down the oxidation of apples.
(a) Sugar solution
Variables: (b) Lime juice
Manipulated: Types of solutions (c) Sodium bicarbonate solution
Responding: Colour change in apple (d) Common salt solution
Form 4
Constant: Size of each slice of apple 3. After 15 minutes, each apple slice was
removed, placed in a Petri dish, then
Materials: left exposed to the air for 30 minutes.
Apple, sugar solution, lime juice, sodium 4. The changes to all the apple slices
bicarbonate solution, common salt solution
were observed after 15 minutes.
Results: Apple
Apple
Apple
Apple
Apple
Apparatus
set-up
Lime juice
Lime juice
Lime juice
Sugar solution
Sugar solution
Lime juice
Common salt
Common salt
Common salt
Common salt
Sodium
Sodium
Sodium
Sodium
Sugar solution
Petri dish
Petri dish
Petri dish
Petri dish
Sugar solution
Petri dish Sugar solution Lime juice Sodium Common salt
solution
bicarbonate
bicarbonate solution
bicarbonate
bicarbonate
bicarbonate
solution
solution
solution
solution
solution
solution
solution
solution
Colour change
in slices of Yes No No Yes No
apple
Discussion: 3. Sodium bicarbonate solution is not an
1. A change in the colour of a slice of antioxidant. Therefore, the apple slice
apple is an indication that oxidation is changed colour.
taking place in the cells of the apple. Conclusion:
2. Sugar solution, lime juice and common Sugar solution, lime juice and the
salt solution slow down the oxidation common salt solution contain antioxidants
rate in the apple. The three solutions and could slow down the oxidation of the
are antioxidants. Therefore, the apple apple. The hypothesis was accepted.
slices did not change colour.
Experiment
VIDEO
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F4 Chapter 10.indd 144 3/21/22 3:24 PM