How to Answer Required Practical Method Questions in AQA GCSE Science

What are Required Practicals?

Practical work is at the heart of science, be that biology, chemistry or physics. The purposes of practical activities are:

• To support your understanding of scientific concepts

• To develop and master practical skills

• To develop investigating skills

AQA have built their courses to recognise the importance of practical work and as part of their courses, you must undertake several different practical activities, as specified by AQA. This isn’t to say that you won’t carry out other practical work and, hopefully, you will experience many other experiments. However, you could get asked questions about the required practicals in your exam, so it is these that you must know about. In fact, around 15% of the overall mark of your science qualification will be based on the knowledge and understanding you have gained when carrying out the required practicals.

The required practical activities for the three sciences are as follows.

GCSE Biology:

1. Microscopy

2. Microbiology

3. Osmosis

4. Food tests

5. Enzymes

6. Photosynthesis

7. Reaction time

8. Plant responses

9. Field investigations

10. Decay

GCSE Chemistry:

1. Making salts

2. Neutralisation

3. Electrolysis

4. Temperature changes

5. Rates of reaction

6. Chromatography

7. Identifying ions

8. Water purification

GCSE Physics:

1. Specific heat capacity 

2. Thermal insulators

3. Resistance

4. I–V characteristics 

5. Density

6. Force and extension

7. Acceleration

8. Waves

9. Light

10. Radiation and absorption

If you are taking Combined Science: Trilogy or Synergy, you need to know about all of these required practical activities except those in bold.

In this article, I will focus on constructing answers for planning a method, which are often worth 6 marks, so it is a vital skill that you should develop. I find this is a skill that students either excel at or really struggle with. If you fall into the latter category, then read on for some essential tips!

What do I need to include in a 6-mark response?

Questions worth 6 marks that start with the words ‘plan an investigation’ or ‘describe a method’ require a bit of careful thought and specific detail. Unlike most other questions, it isn’t a case of just writing six correct points to pick up the marks. These are what are called ‘extended response’ questions which have a ‘level of response’ mark scheme – this means that the marks that you can be awarded are grouped together into different levels, for example, 5 to 6 marks, 3 to 4 marks, 1 to 2 marks and 0 marks. Each level has a description which tells you what sort of answer you would need to give to score that level of mark. 

As an example, the description for an answer that would score you 5 or 6 marks is ‘The method would lead to the production of a valid outcome. All key steps are identified and logically sequenced’. So if you missed out a key step, you would not be able to score 5 or 6 marks.

The process of marking these is not straightforward, and even teachers can sometimes disagree when it comes to marking these! But, the takeaway from this is that you need to be able to structure your answer so that the method you plan includes all the key steps and would produce valid results. 

What do we mean by valid results? Typically, in an investigation, you, the investigator, would change one variable (the independent variable) to find out how this change affects another variable (the dependent variable). An investigation is valid if no other factors could affect the dependent variable, other than the variable that you are changing (the independent variable). So, if you were asked to plan a method that would investigate how the temperature change (the dependent variable) of a neutralisation reaction between an acid and an alkali depended on the concentration of acid (the independent variable) used, you would need to plan a method to ensure that no other factors could affect the temperature change other than concentration. This would mean that you would need to control other variables, such as the volume of acid used, the volume of alkali used and the concentration of alkali used.

To make sure that you have included everything you need to include in your method, you could use the acronym EMMAS. This stands for:

• Equipment

• Method

• Measurements

• Analysis

• Saftey

These are all the key components that you should consider when constructing your answer. Let’s delve into these in a bit more detail.

Method:

Your method needs to contain all of the key steps that would allow you to obtain valid results, i.e. how you will control variables other than the independent variable and dependent variable. It can be bullet-pointed, which can help you to be concise and not include unnecessary detail. (Don’t feel you have to fill the page with writing – sometimes, less is more!) In your method, you should also include:

Equipment:

You need to make sure you state what equipment you will use at each step (for example, if you need to stir a mixture of two solutions together, you should state that you will stir the mixture using a glass rod).

Measurements:

You need to explain what measurements you will take, and it is important to make sure you refer to both the independent and dependent variables. It is also important to explain how you will measure them. For example, if the dependent variable was a temperature change, then just stating ‘take the temperature’ is not sufficiently detailed – you need to spell out how, i.e. take the temperature using a thermometer, or if you were measuring time, record the time taken using a stopwatch. It may seem obvious, but it is vital you spell this out!

It is useful to give a range of values and increments for the independent variable that you would test. For example, if you were investigating how the angle of reflection depends on the angle of incidence, you could state that you would increase the angle of incidence in 10 degree intervals from an angle of incidence of 10 degrees, up to an angle of incidence of 80 degrees. This is especially important if you are given a set of results and asked how you would obtain these results (see the example in Figure 4 below).

Analysis

In some investigations, this is not necessary (for example, if you are planning a method to prepare a salt), but in many practicals, you would need to analyse or process your results in order to answer the question being asked in the investigation. For example, you may have been asked to plan a method to find the density of an irregular-shaped object. To do this, you need to write a method to find the mass of the object and the volume. But, that is not all the information that you need to give as you have not explained how you will use the results to find the density of the material. So, in this example, you would have to include how you would perform the calculation to find density by giving the relevant equation, density = mass ÷ volume.

Safety

Sometimes it is appropriate to include a risk assessment in your response and, in this case, you should include what the hazard is, the risk of that hazard and the precautions you should take to minimise the risk.

Examples of 6-mark responses

Let’s look at a couple of examples to see how we can put this all together. It is important to note that this is not a case of ‘one size fits all’ as each method has different factors that need to be considered, however using the guidance above and ‘EMMAS’ can help you construct your answer.

This first example is a physics question about force and extension:

Source: AQA Website: GCSE Physics Question Paper (Foundation): Paper 2 - November 2021

This question tells you that the investigation is to find the relationship between the force applied to a spring and its extension, so the force would be something that you would vary in the investigation, i.e. it is the independent variable, and you would measure the extension of the spring, the dependent variable. Notice how this question asks you to describe a method that the student could use to obtain the results in Figure 4. This means that your method has to be specific to that set of results. Let’s look at the graph to see what it tells us. In the graph there are five points plotted, corresponding to a force of 1 N, 2 N, 3 N, 4 N and 5 N and the associated extension – so you must describe how to obtain these specific results in your method.

The question also tells you to include a risk assessment for one hazard.

Here is an example of a response that would score 6 marks. Note how the method clearly states what equipment is going to be used, what measurements will be taken and how the results will be analysed to find the extension of the spring. It also considers safety by providing a risk assessment for one hazard.

In this next example from a Chemistry paper, you are asked to plan a method to see the effect of changing the mass of sodium carbonate powder on the highest temperature reached when hydrochloric acid is added.

Source: AQA Website: GCSE Chemistry Question Paper (Higher): Paper 1 - June 2022

In this investigation, you will change the mass of the sodium carbonate, so this is the independent variable. The dependent variable is the temperature change. In this method, it is particularly important to control certain variables so that the outcome is valid.

Notice here, that you do not need to analyse the results and you are not given any credit for identifying any hazards. It is always worth considering this though, as the question could ask specifically for a risk assessment as in the first example.

For this practical, you could give:

• Hazard: Acids can be an irritant.

• Risk: Acid could cause damage to the skin.

• Precaution: Wash skin if it comes into contact with acid.

Summary

• There are a wide range of required practicals for which you could be asked to describe a method and these questions are typically worth 6 marks.

• You need to know the method for each practical and your response should include all of the key steps to lead to a valid outcome. 

• You can use the acronym EMMAS as a way to double-check that you have included the key points, although not all of these will be needed for each practical. 

• EMMAS stands for:

  • Equipment

  • Method

  • Measurements

  • Analysis

  • Safety

You can visit the other resources available at Save My Exams for AQA GCSE Biology,  AQA GCSE Chemistry and AQA GCSE Physics. Alternatively, you can visit our GCSE Revision overview page to see resources from other exam boards.