ISA - Controlled Assessment

The ISA will make up 25% of your marks towards your GCSE. It is made up of 2 parts:

1. Planning

Before you sit down to do the Section 1 question paper you'll be given a hypothesis/prediction. You will then need to research the topic that's been set and two different methods to test the hypothesis. In your research, you should use a variety of different sources (e.g. internet, textbooks etc.). You will need to be able to outline both methods and say which is best (and why is is the best) and describe your preferred method in detail. You're allowed to write notes about your two methods on one side of A4 and have them with you for both question papers, a template of this can be downloaded below. You could be asked things like:

1) What variables you're going to control (and how you're going to control them).

2) What measurements you're going to take.

3) What range and interval of values you will use for the independent variable.

4) How you will figure out the range and interval using a trial run (preliminary investigation).

5) How many times you're going to repeat the experiment - Hint: 3 is a good idea.

6) What equipment you are going to use (and why that equipment is right for the job).

7) How to carry out the experiment ( method ).

8) What hazards are involved in doing the experiment and how to reduce them.

9) What table you'll draw to put your results in.

2. Do the experiment!

After planning your experiment you will have to carry out the experiment and record your findings.

3. Drawing Conclusions and Evaluating

For Section 2 question paper you have to do these things for your experiment:

1) Analyse and draw conclusions from your results. For this you need to describe the relationship between the variables in detail.

Good words to describe the relationship:

Positive Correlation - Strong and Weak - As one variable increases the other increases.

Negative Correlation - Strong and Weak - As one variable increases the other decreases.

No Correlation - There's no relationship between the two variables. Hint : When data is scattered.

Linear - The graph is a straight line.

Directly Proportional - The graph is a straight line where both variables increase or decrease in the same ratio.

Example of Hypothesis:  The survival and growth of microorganisms depends upon the concentration of disinfectant.

Equipment : Nutrient broth pre-inoculated with safe bacteria (labelled “safe bacteria”), 5 test tubes,
Syringes or other means of measuring volumes of 0.5cm³and 5cm³, 5 sterile nutrient agar plates,

Incubator at 25^oC, Disinfectant solution, diluted to double normal working strength (refer to label on bottle used), Means of labelling tubes and agar plates, Inoculating loop and a Bunsen burner.

Method:

Firstly, prepare 5 petri dishes with the sterile technique.

1. Label 5 test tubes 1 to 5.

2. Put 10cm3 of the disinfectant into test tube 1.

3. Remove 5cm3 from test tube 1 into test tube 2.

4. Add a further 5cm3 of water to test tube 2.

5. Remove 5cm3 from test tube 2 into test tube 3.

6. Add a further 5cm3 of water to test tube 3.

7. Repeat this process to make test tubes 4 and 5.

8. Remove 5cm3 of solution from test tube 5 and discard it.

9. Add 0.5cm3 of bacteria to each of the five test tubes. Shake the test tube to mix.

10. Cut out 5 circles that have 3cm in diameter and dip them into each test tube.

11. Carefully put each circle into a petri dish, remembering to label the petri dishes.

12. Leave in Incubator and wait for 3-4 days and count the number of bacteria colonies.

If in class you are studying this topic, remember to include the website link to your sources.

Template of Planning Sheet : http://e7f4fce2.linkbucks.com

*For Step-by-Step Guide of how to download, please see the homepage.