Page 182 - Science Coursebook

Reference

Activity
Designing a better experiment

Scientists think that the fish oil experiment was not well designed.

In your group, discuss these questions:
1 If the researchers wanted to find out whether students who took fish oil tablets
did better in their exams than students who didn’t, what should they have done
right at the start of their experiment?
2 How many students stopped taking the fish oil tablets before they took their
exams? Think of reasons why some students might have stopped taking the
tablets, while others carried on (continued) taking them.
3 What do you think of the ‘matched pairs’ idea, for comparing students who took
tablets with those who did not?
4 The results did show that the students who had taken fish oil did better in their
exams that the students who did not. But does this really mean that it was taking
the fish oil that made the difference? Can you think of any other explanations?
5 Imagine you were given the task of designing an experiment to find out if taking
fish oil tablets for one year improves performance in exams. Write down exactly
what you would do.

Electric circuit symbols
ammeter A

buzzer

cell

connecting wire
connecting wires crossing

connecting wires joined
lamp V

M
motor V
resistor M

switch, open
V
switch, closed
M
variable resistor
V V
voltmeter V
M M

180 M