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Ca revision

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Claire Gaukrodger
Claire Gaukrodger

This document provides guidance for students completing the controlled assessment (CA) unit for the AQA Science B qualification. It outlines the key areas being assessed and the marks available for each section. These include researching, planning, risk assessment, collecting and processing data, analysis, and evaluation. Examples are given for writing aims, methods, identifying variables, predictions, tables, graphs, and evaluation. Formatting guidelines and writing frames are also provided to help students structure their responses. The overall aim is to help students gain the maximum marks across the 48 marks available for the CA.

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AQA Science B Controlled Assessment Learning Objective: Revise the key areas included in the Science controlled assessment unit
Guide to the CA Section Marks Awarded 際際滷 Pictogram 1: Research 4 2: Planning 8 3: Managing and Assessing 8 Risk 4: Collecting Data 8 5: Processing Data 10 6: Analysing Data 6 7: Evaluating the Practical 6 Activity Total 48
Starter: Match the Keywords Aim How will you carry out your experiment? Dependent Variable What are you trying to find out? Method What are you deliberately changing in your experiment? Control variable What equipment will you use? Independent Variable What are you going to measure? Prediction What variables will you keep the same? Based on scientific knowledge what do you think the Apparatus relationship is between the dependent and Independent variables
Constructing Aims The purpose of my experiment is to investigate................................... Writing Frame (a statement discussing the effect of the independent variable on the dependent variable) To gain the full marks in this area you must mention both the independent and dependant variables i.e. Aim: To measure the effect of changing the temperature on the rate of a chemical reaction by timing how long it takes the cross to disappear with different temperatures of Sodium thiosulphate are reacted with hydrochloric acid .
Methods BAD GOOD I filled half of the crucible 1. Half fill the crucible with with alcohol. Then I put alcohol. 50ml of water in the beaker 2. Put 50ml of water in the and measure the beaker and measure the temperature. I then set up temperature. the equipment as shown in 3. Set up the equipment as the diagram and put my shown in the diagram. goggles on. I lit the alcohol and burned for 5 mins. I 4. Put your goggles on. measured the temperature 5. Light the alcohol and burn and recorded it in the table. for 5 minutes 6. Measure the temperature and record in the table. Think of your method as a recipe. It should be a set of clear steps in a PASSIVE VOICE.
Identifying Variables 1. Finding the effect of string length on the time of pendulum swing. 2. Finding how the number of coils affects the number of clips that the electromagnet can pick up. 3. Measuring the temperature of water as it is being heated. 4. Investigating the effect of different types of exercise on pulse rate. 5. Investigating the effect of Caffeine on a persons reaction time Identify the INDEPENDENT, DEPENDANT and 2 possible CONTROL variables for each experiment
Predictions: Describing relationships As (independent) increases/decreases Writing Frame: will increases/decrease (dependent) because.. (scientific knowledge) To gain the full marks in this area you must link the independent and dependant variables and use information from your research to support your educated guess i.e. Aim: to measure the temperature of water as it is being heated. Prediction: As the time the beaker is over the Bunsen increases the temperature of the water will increase until the temperature of the water reaches 100oC as this is the boiling point of water. Initially the temperature will increase because as the water particles are heated they vibrate faster, their kinetic energy is transferred into heat energy. However once their boiling point is reached they have enough kinetic energy to change state from liquid to a gas, so steam will be produced.
Managing and Assessing Risk Place all of your apparatus in Equipment/Ch Hazard Risk Control emical Measure table and use your own knowledge and HAZCARDS to Magnesium Irritant: Can Medium as it Clear up sulphate damage skin can be spilt spillages complete (0.1M) cause slips easy and immediately or falls if looks like using paper Apparatus (Equipment) spilt water so you towels. Wash Magnesium sulphate (0.1M) might forget hands after to wash it off practical, Zinc sulphate (0.1M) wear goggles Test tube rack Zinc sulphate 4 test tubes (0.1M) measuring cylinder Spatula Carrying out Electronic balance the experiment Look at the full example Tin that your teacher shows Iron Glassware you. Electronic balance Dont forget to record the Tin sources that you use Iron
Drawing Tables Independent Dependant Variable (Units) Variable (Units) 1 2 3 Mean Exclude any anomalous repeats when All data to 2 Decimal Points calculating the mean. Make sure you show which ones have been excluded. This is the standard table. You may need a slightly different one if you are not doing repeats
Bar Charts Categoric Data Title Graph showing the mean reaction times of No marks 4 students Straight lines for but 5 plotting essential 4 Dependant Variable e.g. Mean Reaction Time (s) 3 Key Correctly Reaction Time labelled, appr 2 (s) opriately Even bars scaled Y axis 1 with units 0 Kate Mary Bob Peter Independent variable e.g. Pupil N.B. The title of the axes Correctly labelled appropriately scaled Are the same as the X axis with units Headings of the table!!
Line Graph Continuous Data Title No marks Graph showing the mean temperature Clear Dependant Variable e.g. but change (oC) over 40s plotting Mean temperature (oC) 50 essential 40 Key (if needed) 30 20 Column1 10 0 Line of best 10 20 30 40 fit Correctly labelled Independent Variable e.g. Time (s) appropriately scaled Y axis Correctly labelled, appropriately scaled X with units axis with units N.B. The title of the axes Are the same as the Headings of the table!!
Processing Data: Comment on the Graph Describe what your graph shows. Make a link between the independent and dependent variables. Does it match your prediction. Make direct reference to parts of your graph by quoting numbers/points from it. Increase Decrease Writing Frame Directly proportional Keywords: Linear Stays the same Double Halved
Analysing Data Step 1: What are the findings of your experiment? Use an ER statement i.e. The smaller the wood the quicker it burns Step 2: Explain your ER Statement using information from your experiment to back it up Step 3: Compare your results to the results from the secondary data do they support/contradict your conclusion? How? Step 4: What are the limitations of your primary and secondary data? How could you overcome this?
Evaluation Step 1. Comment on the practical, was your method good? Did it enable you to collect valid results? Did you have any anomalies? What did you do about it? Strengths Weaknesses Step 2. Evaluate your working methods. What were your strengths and weaknesses Improvements to be Reasons Step 3. What improvements made could you make and why would this be of benefit?
Step 1 Comment on I did lots of repeats to make sure that I could reliability ignore any anomalous results Tips for your Evaluation The experiment was valid because there was only one independent variable, the pH and everything Comment on else, like the light and temperature was controlled. Validity and fair testing I used the same number of seeds and volume of solution in each test so that it was fair. Step 2 Improvement for getting more data I only looked at the height of the cress seedlings. I could have measured the width and colour of the leaves as well. Improvement for The heights were all very small, so if I measured getting better them over a period of several weeks, I could see if data the pH affected the growth over a period of time. I could also have seen if pH slowed down Improvement for germination, rather than stopped it. greater accuracy I could have made it more accurate by using vernier calipers to measure the height of the seedlings.
Lastly: Quality of Written Communication Level Key Points (get up to 6 extra marks) 1 Knowledge of basic information Simple understanding Answer is poorly organised with few keywords . Spelling, punctuation and grammar is weak 2 Knowledge of accurate information Clear understanding Answer has some structure, some keywords used but not always accurately. Spelling, punctuation and grammar is reasonably accurate. 3 Knowledge of accurate contextualised information Detailed understanding supported by evidence Sequenced, structured and organised answer with appropriate use of keywords Spelling, punctuation and grammar is faultless

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Ca revision

  • 1. AQA Science B Controlled Assessment Learning Objective: Revise the key areas included in the Science controlled assessment unit
  • 2. Guide to the CA Section Marks Awarded 際際滷 Pictogram 1: Research 4 2: Planning 8 3: Managing and Assessing 8 Risk 4: Collecting Data 8 5: Processing Data 10 6: Analysing Data 6 7: Evaluating the Practical 6 Activity Total 48
  • 3. Starter: Match the Keywords Aim How will you carry out your experiment? Dependent Variable What are you trying to find out? Method What are you deliberately changing in your experiment? Control variable What equipment will you use? Independent Variable What are you going to measure? Prediction What variables will you keep the same? Based on scientific knowledge what do you think the Apparatus relationship is between the dependent and Independent variables
  • 4. Constructing Aims The purpose of my experiment is to investigate................................... Writing Frame (a statement discussing the effect of the independent variable on the dependent variable) To gain the full marks in this area you must mention both the independent and dependant variables i.e. Aim: To measure the effect of changing the temperature on the rate of a chemical reaction by timing how long it takes the cross to disappear with different temperatures of Sodium thiosulphate are reacted with hydrochloric acid .
  • 5. Methods BAD GOOD I filled half of the crucible 1. Half fill the crucible with with alcohol. Then I put alcohol. 50ml of water in the beaker 2. Put 50ml of water in the and measure the beaker and measure the temperature. I then set up temperature. the equipment as shown in 3. Set up the equipment as the diagram and put my shown in the diagram. goggles on. I lit the alcohol and burned for 5 mins. I 4. Put your goggles on. measured the temperature 5. Light the alcohol and burn and recorded it in the table. for 5 minutes 6. Measure the temperature and record in the table. Think of your method as a recipe. It should be a set of clear steps in a PASSIVE VOICE.
  • 6. Identifying Variables 1. Finding the effect of string length on the time of pendulum swing. 2. Finding how the number of coils affects the number of clips that the electromagnet can pick up. 3. Measuring the temperature of water as it is being heated. 4. Investigating the effect of different types of exercise on pulse rate. 5. Investigating the effect of Caffeine on a persons reaction time Identify the INDEPENDENT, DEPENDANT and 2 possible CONTROL variables for each experiment
  • 7. Predictions: Describing relationships As (independent) increases/decreases Writing Frame: will increases/decrease (dependent) because.. (scientific knowledge) To gain the full marks in this area you must link the independent and dependant variables and use information from your research to support your educated guess i.e. Aim: to measure the temperature of water as it is being heated. Prediction: As the time the beaker is over the Bunsen increases the temperature of the water will increase until the temperature of the water reaches 100oC as this is the boiling point of water. Initially the temperature will increase because as the water particles are heated they vibrate faster, their kinetic energy is transferred into heat energy. However once their boiling point is reached they have enough kinetic energy to change state from liquid to a gas, so steam will be produced.
  • 8. Managing and Assessing Risk Place all of your apparatus in Equipment/Ch Hazard Risk Control emical Measure table and use your own knowledge and HAZCARDS to Magnesium Irritant: Can Medium as it Clear up sulphate damage skin can be spilt spillages complete (0.1M) cause slips easy and immediately or falls if looks like using paper Apparatus (Equipment) spilt water so you towels. Wash Magnesium sulphate (0.1M) might forget hands after to wash it off practical, Zinc sulphate (0.1M) wear goggles Test tube rack Zinc sulphate 4 test tubes (0.1M) measuring cylinder Spatula Carrying out Electronic balance the experiment Look at the full example Tin that your teacher shows Iron Glassware you. Electronic balance Dont forget to record the Tin sources that you use Iron
  • 9. Drawing Tables Independent Dependant Variable (Units) Variable (Units) 1 2 3 Mean Exclude any anomalous repeats when All data to 2 Decimal Points calculating the mean. Make sure you show which ones have been excluded. This is the standard table. You may need a slightly different one if you are not doing repeats
  • 10. Bar Charts Categoric Data Title Graph showing the mean reaction times of No marks 4 students Straight lines for but 5 plotting essential 4 Dependant Variable e.g. Mean Reaction Time (s) 3 Key Correctly Reaction Time labelled, appr 2 (s) opriately Even bars scaled Y axis 1 with units 0 Kate Mary Bob Peter Independent variable e.g. Pupil N.B. The title of the axes Correctly labelled appropriately scaled Are the same as the X axis with units Headings of the table!!
  • 11. Line Graph Continuous Data Title No marks Graph showing the mean temperature Clear Dependant Variable e.g. but change (oC) over 40s plotting Mean temperature (oC) 50 essential 40 Key (if needed) 30 20 Column1 10 0 Line of best 10 20 30 40 fit Correctly labelled Independent Variable e.g. Time (s) appropriately scaled Y axis Correctly labelled, appropriately scaled X with units axis with units N.B. The title of the axes Are the same as the Headings of the table!!
  • 12. Processing Data: Comment on the Graph Describe what your graph shows. Make a link between the independent and dependent variables. Does it match your prediction. Make direct reference to parts of your graph by quoting numbers/points from it. Increase Decrease Writing Frame Directly proportional Keywords: Linear Stays the same Double Halved
  • 13. Analysing Data Step 1: What are the findings of your experiment? Use an ER statement i.e. The smaller the wood the quicker it burns Step 2: Explain your ER Statement using information from your experiment to back it up Step 3: Compare your results to the results from the secondary data do they support/contradict your conclusion? How? Step 4: What are the limitations of your primary and secondary data? How could you overcome this?
  • 14. Evaluation Step 1. Comment on the practical, was your method good? Did it enable you to collect valid results? Did you have any anomalies? What did you do about it? Strengths Weaknesses Step 2. Evaluate your working methods. What were your strengths and weaknesses Improvements to be Reasons Step 3. What improvements made could you make and why would this be of benefit?
  • 15. Step 1 Comment on I did lots of repeats to make sure that I could reliability ignore any anomalous results Tips for your Evaluation The experiment was valid because there was only one independent variable, the pH and everything Comment on else, like the light and temperature was controlled. Validity and fair testing I used the same number of seeds and volume of solution in each test so that it was fair. Step 2 Improvement for getting more data I only looked at the height of the cress seedlings. I could have measured the width and colour of the leaves as well. Improvement for The heights were all very small, so if I measured getting better them over a period of several weeks, I could see if data the pH affected the growth over a period of time. I could also have seen if pH slowed down Improvement for germination, rather than stopped it. greater accuracy I could have made it more accurate by using vernier calipers to measure the height of the seedlings.
  • 16. Lastly: Quality of Written Communication Level Key Points (get up to 6 extra marks) 1 Knowledge of basic information Simple understanding Answer is poorly organised with few keywords . Spelling, punctuation and grammar is weak 2 Knowledge of accurate information Clear understanding Answer has some structure, some keywords used but not always accurately. Spelling, punctuation and grammar is reasonably accurate. 3 Knowledge of accurate contextualised information Detailed understanding supported by evidence Sequenced, structured and organised answer with appropriate use of keywords Spelling, punctuation and grammar is faultless

Editor's Notes

  1. With thanks to SJC22 on the TES