Teacher's notes and answers to questions in the book - Hodder Plus ...

WJEC GCSE Additional Science Teacher’s Notes
PRACTICAL What’s in cigarette smoke (page 53)
1. Suggest a reason for the colour change in the indicator.
Carbon monoxide and carbon dioxide produced by the burning of tobacco are acid gases.
2. Good practice in this experiment is to first suck air through an unlit cigarette for 10 minutes. Suggest
a reason for this.
To ensure that changes are due to tobacco smoke and not atmospheric air (passing through
the tobacco).
3. The colour and smell of the cotton wool shows the presence of tar. It is difficult to measure colour or
smell. Suggest how the procedure could be adjusted so that the amount of tar in two different types
of cigarettes could be compared.
The cotton wool could be weighed before and after the experiment.
_How have attitudes to smoking changed __________
(pages 53–54)
TASK What are the dangers of passive smoking
(page 54)
In the report to be written for this section, pupils are asked to consider bias. A common
misunderstanding is that anything reported by a biased website is untrue. Pupils should
understand that bias is often evident in the selection of information reported and ‘skewed’
interpretation of data. Sometimes, however, biased groups can present reliable information.
This is usually when their particular bias aligns with the scientific evidence.
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