Investigations

1. Investigations

2. How to carry out a typical investigation • Think about what you could investigate • Decide upon the independent variable • ie what are you going to change in the investigation • Decide how you are going to measure the independent variable and what values you are going to use • Decide upon the dependent variable • ie what outcome are you going to measure • Decide how you are going to measure the dependent variable • Think about all the other variables that could affect the results of your investigation and keep them the same (control variables) • Think about what equipment you could use to get accurate measurements • Repeat your measurements to check that they are reliable

3. Lee blew across the top of paper tubes to make sounds. He investigated how changing the length of a tube affects the pitch of the sound. What was the independent variable ? length of tube What was the dependent variable ? pitch of the sound eg same width of tubes Name a control variable ? Abdul carried out an investigation to find out whether temperature affected how quickly food went off. What was the independent variable ? temperature What was the dependent variable ? time for food to go off Name a control variable ? eg same type of food

4. John carried out an investigation to find out which colour light makes plants grow the best. What was the independent variable ? colour of light What was the dependent variable ? growth of plants eg same amount of water Name a control variable ? eg height How could he measure the growth of the plants ? Ayesha carried out an investigation to find out which type of plastic makes the strongest bag. different types of plastic What was the independent variable ? strength of bags What was the dependent variable ? eg same size bags Name a control variable ? How could she measure the strength of the bags ? put weights in the bag till it tears What would be the dependent variable now ? weight

5. You have got 9 min to answer these questions

6. Write down a question you could investigate. eg does the mass of the person affect the time for one swing What will be the independent variable ? mass or length of chains What will be the dependent variable ? time for one swing mass / length of chains + number of swings What will you have to keep the same ?

7. What was he doing with A and B ? keeping the length the same and changing the mass What was he doing with C and D ? keeping the mass the same and changing the length Write a conclusion for his results. changing the mass does not affect the time for 10 swings increasing the length of string increases the time for 10 swings

8. This is an investigation where the temperature is changed and the solubility of CuSO4 is measured. Using the same volume of water makes it a fair test. Till no more dissolves determines the mass of CuSO4 added When a solution is saturated it means you can’t dissolve any more salt in it. They changed the temperature and the measured outcome was the mass of copper sulphate dissolved to make a saturated solution. There is a lot of text in this question. You need to go through it carefully, bit by bit. temperature What was the independent variable ? mass of CuSO4 dissolved What was the dependent variable ? Name a control variable ? eg same volume of water

9. Plot a curve of best fit The anomalous result is below what would be expected so maybe the temperature was less than 60oC for that point. Circle an anomalous result Suggest what could have produced the anomalous result Write a conclusion for this investigation Increasing the temperature increases the mass of dissolved copper sulphate The higher the temperature the greater the mass of dissolved copper sulphate

10. You have got 5 min to answer these questions

11. What was the independent variable ? shape of tea bag What was the dependent variable ? time for tea to dissolve eg same volume of water, same temperature etc Name a control variable ? What is missing from this plan ? eg no detail, hasn’t stated what will be measured etc Why is this a better plan ? eg has stated what will be measured, has stated a method etc

13. Harry investigated the effects of fizzy cola drink on his heart rate x (b) Put an X on the graph to show when Harry drank the cola.

15. These questions are not on the hand out Harry now decided to investigate the effects of different fizzy drinks on his heart rate different fizzy drinks What would be the independent variable ? heart rate What would be the dependent variable ? eg same volume of drinks Name a control variable ?

16. You have got 9 min to answer these questions

17. Some pupils carried out an investigation to find out whether more sugar or more salt dissolved in water at 60oC. What was the independent variable ? kind of substance eg sugar and salt What was the dependent variable ? mass of salt dissolved Name a control variable ? eg same volume of water

18. Set up 20 vases with the same volume of water and nutrients. Put modified plants in 10 vases and unmodified plants in the other 10 vases. Make sure that all the plants are the same size to start off with. Measure the freshness every week for 8 months. How would you investigate this claim ? the kind of plant What would be the independent variable ? the freshness of the plants What would be the dependent variable ? eg same volume of water Name a control variable ?

20. Some interesting questions ….