HSW – Answering AS questions How Science Works Answering AS questions Version 1.01 Copyright © 2008 AQA and its licensors. All rights reserved

HSW – Answering AS questions

How Science Works

Answering AS questions

Version 1.0 1 Copyright © 2008 AQA and its licensors. All rights reserved.



What have mosquitoes to do with your specification?

Look at the Assessment Objectives

AO2 Application of knowledge and understanding of science and of How Science Works

Candidates should be able to: • apply scientific knowledge …to unfamiliar situations



What have mosquitoes to do with your specification?

Look at the Assessment Objectives (p46)

AO3 How Science Works

Candidates should be able to • analyse, interpret, explain and evaluate the methodology, results and impact of … others’ experimental and investigative activities.


What this means to you

Your examiners must test these assessment objectives.

Therefore your Unit tests must include

•Opportunities for you to apply your knowledge to unfamiliar situations

•Examples of others’ experimental and investigative activities for you to analyse, interpret, explain and evaluate




Read the introduction to the question

• Mosquitoes are insects

• Some female mosquitoes feed on human blood.

• They are attracted to humans and land on exposed skin.

• They then pierce the host’s skin and suck blood.

The introduction may provide you with information that you will need later.

Title of presentation


A simple start

The first parts of most longer questions are often quite simple. Examiners appreciate that giving you something that is easy at the start gives you confidence.

1Both of these traps used heat and carbon dioxide to attract mosquitoes. Explain how each of these might attract a mosquito to a human. (a) Heat (b) carbon dioxide

Remember, the only reason that a question looks simple is because it is simple. No one is trying to trick you.



Looking at other people’s investigationsWhat were the scientists investigating?• Start by identifying the dependent and independent

variables • Put them in this simple template.

The effect of [the independent variablethe independent variable] on the [dependent variabledependent variable]

• In this case . . . The effect of [the type of trapthe type of trap] on the [number of number of mosquitoes caughtmosquitoes caught]

Having a clear idea what the investigation is about is an essential first step towards understanding any investigation.



Looking at other people’s investigations

• Take time to make sure that you understand exactly what they did.

The scientists moved the traps randomly between 12 different sites over 12 nights. Each night the traps were at a different site.

Sometimes a simple drawinghelps

12 different sites







Night 1Trap A

Trap B







Night 2

Trap A

Trap B



Looking at other tables• Read the stem of the question.• Make sure that you know what the table headings mean.• Check that you understand what the table as a whole is

telling you.

Here you only need to make sure that you know what the table headings mean



Check the headings

• Mean tells us the average – the total number of mosquitoes caught divided by the number of nights.

• Standard deviation is a measure of how spread out the results were.



Looking at tables

Total number of species of mosquito trapped is quite straightforward



Looking at tables

There are two things to note here. •The data refer to the percentage of mosquitoes.

•These are mosquitoes that are potentially able to transmit Ross River fever. It does not mean that they do.



Calculations

3 The total number of mosquitoes caught in trap A was 444 90. Calculate the total number of mosquitoes caught in trap A that were able

to transmit Ross River fever. Show your working.

Look at the section on Mathematical Requirements on page 45 of your specification. Your examiners may ask you to use any of the areas of mathematics listed here - not the ones in bold



Calculations – some hints• Even if you are not very good at mathematics, you should

be able toCalculate a rateCalculate a percentageCalculate magnification and size

Most questions involve one of these

• Always have a go. Don’t leave out any question that involves a calculation.

• Show your working. Even if you get the answer wrong, you could still get a mark for going about the problem in the right way.



Evaluating data• Evaluation means to judge the worth of something. • Data that you have to evaluate will have some evidence

that will support the idea and some that will not.

4 Evaluate the data in the table and suggest which trap it would be better to use.



A strategy for evaluating data

Questions requiring evaluation require you to judge the worth of something. Some evidence will support the idea and some will not.

Look for evidence that supports the ideaYou will need to look for the overall trend in the points on a graph or the figures in a table to establish this.

Now look for ways in which the evidence is unconvincing

The key is to get the word “but” into the answer.



Looking at graphs• Read the stem of the question

• Make sure that you know what the axis labels mean.

• Check that you understand what the graph as a whole is telling you.



Looking at graphs• Read the stem of the question

The graph shows the mean number of landings at different distances from the source of the repellent. It also shows the effect of using new repellent and old repellent. The old repellent had been opened 10 weeks earlier.

• The stem provides you with a summary of the information in the graph. It may also give you extra information that you may need when you answer the questions.



Mean numberof mosquitoes landing per minute


Shouldn’t be a problem here –

the average number landing

on the volunteer’s arm

per minute





and these are the three treatments

Don’t forget to look at the

key


• Check that you understand what the graph as a whole is telling you



This bar shows us that when the volunteers were 3.0 metres away from new repellent the mean number of mosquitoes landing per minute was about 1.5

Copyright © 2010 AQA and its licensors. All rights reserved.

The Assessment and Qualifications Alliance (AQA) is a company limited by guarantee registered in England and Wales (company number 3644723)and a registered charity (registered charity number 1073334). Registered address: AQA, Devas Street, Manchester M15 6EX.

Dr Michael Cresswell, Director General.



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HSW – Answering AS questions How Science Works Answering AS questions Version 1.01 Copyright © 2008 AQA and its licensors. All rights reserved