AQA GCSE Physics How Science Works

1
AQA GCSE PhysicsHow Science Works

• GCSE Physics pages 2 to 21

2
Fundamental ideas about how science worksNotes
questions from pages 4 5

• Give an example in each case of an opinion based
  on scientific evidence and one based on
  non-scientific evidence.
• List the different types of variable and give an
  example of each.
• How can you check on the reliability of an
  investigation?
• What is required for an investigation to be
  valid?
• List, and give examples of the ways in which a
  dependent variable might be linked to an
  independent variable.
• Copy and answer questions (a), (b), (c) and (d)
  on pages 4 and 5.
• Copy the Key Points on page 5.
• Answer the summary questions on page 5.

3
Fundamental ideas about how science works ANSWERS

• In text questions
• The original animal experiment did not include
  pregnant animals/was not carried out on human
  tissue, and so was not valid, when the opinion
  was formed that it could be given to pregnant
  women.
• Using a voltmeter. Continuous measurements
  (variables) are more powerful.
• Control all (or as many as possible) of the other
  variables.
• Check example.

• Summary questions
• 1. (a) categoric
• (b) ordered
• (c) continuous
• 2. The investigation can be shown to be reliable
  if other scientists can repeat their
  investigations and get the same findings. Because
  it is reliable, opinions formed from it are more
  useful

4
Starting an investigation Notes questions from
pages 6 7

• (a) What is a hypothesis? (b) Give an example of
  a hypothesis. (c)
• Explain the process by which an initial
  observation can lead on to an investigation.
• Distinguish between and give examples of (a) an
  independent variable (b) a dependent variable
  (c) a control variable.
• Copy and answer questions (a), (b), (c) and (d)
  on pages 6 and 7.
• Copy the Key Points on page 7.
• Answer the summary questions on page 7.

5
Starting an investigation ANSWERS

• In text questions
• Yes or No. Reasons needed.
• Any three from
• The second driver was tired.
• The second car was driving too fast.
• The second car was travelling too close.
• The first car had no brake lights
• For example
• Observation bridge is twisting.
• Hypothesis high wind velocity caused it to
  twist.
• (d) He did not use blackout, light was coming
  from other sources. The results are not valid.

• Summary questions
• Observations when supported by scientific
  knowledge can be used to make a hypothesis. This
  can be the basis for a prediction. A prediction
  links an independent variable to a dependent
  variable. Other variables need to be controlled.
• A hypothesis seeks to explain an observation it
  is a good idea.
• A prediction tests a hypothsesis in an
  investigation.

6
Building an investigation Notes questions from
pages 8 9

• (a) What is meant by a fair test? (b) Describe an
  example of a fair test. (c) What is the purpose
  of a control group?
• Why is a a preliminary test or trial run a good
  idea?
• Draw the diagrams on page 9 and explain the
  difference between accurate and precise results.
• What steps can be taken to obtain (a) accurate
  and (b) precise results?
• How can the reliability of results be determined?
• Copy and answer questions (a) and (b) on pages 8
  and 9.
• Copy the Key Points on page 9.
• Answer the summary questions on page 9.

7
Building an investigation ANSWERS

• In text questions
• Any variables associated with the weather, the
  track surface, fuel used, driver, must vary in
  the same way for each test.
• Diagram of thermometer showing the true value
  with 4 readings tightly grouped around it.

• Summary questions
• 1. Trial runs give you a good idea whether you
  have the correct conditions whether you have
  chosen the correct range whether you have enough
  readings if you need to do repeat readings.
• 2. Example I measured the resistance of the
  wire as 3.5 ohms, 4.8 ohms, 2.2 ohms, 3.8 ohms
  and 3.2 ohms. The average of my results is 3.5
  ohms and the manufacturers results are 3.5 ohms.
  My results were accurate but not precise.
• 3. Control all the variables that might affect
  the dependent variable, apart from the
  independent variable whose values you select.

8
Making measurements Notes questions from pages
10 11

• (a) What is meant by the sensitivity of a
  measuring instrument. (b) What is the sensitivity
  of (i) your ruler (ii) your protractor?
• Copy and answer questions (a), (b) and (c) on
  page 10.
• Explain with examples what is meant by (a) random
  and (b) systematic error.
• Copy and answer questions (d) and (e) on page 11.
• (a) What is an anomalous result? (b) what should
  you do when you have identified an anomalous
  result in an investigation?
• Copy the Key Points on page 11.
• Answer the summary questions on page 11.

9
Making measurements ANSWERS

• In text questions
• Generally a failure to control variables. For
  example the trolley might not take the same
  route. Also the student might not react as
  quickly when stopping watch.
• Student is standing too far away and at the wrong
  angle to see when the trolley reaches the line.
• Sailing 1 hour
• Car 0.1 seconds
• Pendulum 1.0 seconds
• Pizza 1 minute
• (d) First attempt for b is the random error.
• (e) Average results are close to individual
  results, which are consistently different to the
  calculated time.

• Summary questions
• There will always be some variation in results.
  You should always chose the best instruments that
  you can to get the most accurate results. You
  must know how to use the instrument properly. The
  sensitivity of an instrument refers to the
  smallest change that can be detected. There are
  two types of error, random and systematic.
  Anomalies should be discarded.
• (a) systematic, (b) random.

10
Presenting data Notes questions from pages 12
13

• (a) Why are results tables a good idea? (b) When
  should they be designed? (c) What should they
  contain?
• A student is investigating how the temperature
  difference between some hot water and the
  laboratory varies in time. Design a suitable
  results table.
• What is meant by the (a) range and (b) mean of
  data?
• Copy and answer question (a) on page 13.
• List the various graphical ways of presenting
  data and state which method suits which type of
  variable.
• Copy the Key Points on page 13.
• Answer the summary questions on page 13.

11
Presenting data ANSWERS

• In text questions
• Dependent variable -
• 150 O
• to 4000 O

• Summary questions
• Missing word order is
• range, mean, categoric, continuous
• 2. Appropriate line graph drawn.

12
Using data to draw conclusions Notes questions
from pages 14 15

• (a) State the ways in which a line of best bit
  can be used. (b) Can such a line be curved?
• Copy, along with Figure 1, and answer question
  (a) on page 14.
• (a) What is meant by a directly proportional
  relationship? (b) How does a graph showing such a
  relationship differ from one showing only a
  positive linear relationship?
• Give an example of a complex relationship and
  show how it might be represented graphically.
• Write your own notes on the section under
  Drawing conclusions on page 15.
• How can you check the reliability and validity of
  your results?
• Copy the Key Points on page 15.
• Answer the summary questions on page 15.

13
Using data to draw conclusions ANSWERS

• In text questions
• (i) Positive linear relationship.
• (ii) Negative linear relationship.

• Summary questions
• Missing word order is
• anomalous, positve, negative, directly, complex.
• 2. Survey of substations measure voltage drop
  measure microteslas at different distances
  from the substation also in houses well away
  from substations repeat all readings several
  times fieldwork check accuracy of measuring
  instruments.

14
Scientific evidence and society Notes questions
from pages 16 17

• Read the chapter and then answer the questions
  under the section Learning Objectives on page
  16.
• Copy and answer questions (a) and (b) on page 16.
• Copy the Key Points on page 17.
• Answer the summary question 1 and 3 on page 17.

15
Scientific evidence and society ANSWERS

• In text questions
• For example What level of X-rays are safe? if
  they are safe should they be limited? what
  evidence is there? what is meant by limited?
  who did the research?
• Did she repeat her tests? did she get someone
  else to repeat them? what instruments were
  used? what was the sensitivity of the
  instruments? how were the readings of noise
  level taken?

• Summary questions
• Missing word order is
• balanced, bias, political, status.
• 3. Should be independent. Should have the
  necessary skills as a scientist. should not be
  capable of being influenced politically.

16
How is science used for everybodys benefit?
Notes questions from pages 18 19

• Read the chapter and then answer the questions
  under the section Learning Objectives on page
  18.
• Copy the Key Points on page 19.
• Answer the summary questions on page 19.

17
How is science used for everybodys benefit?
ANSWERS

• Summary questions
• That radioactivity could pass through certain
  materials and be absorbed by others.
• From the passage smoke detectors, clocks,
  diagnosis and cure of cancer, electricity
  production, bombs, research into atomic
  structure, toothpaste(!). Others possible.
• (a) (i) For example used in warfare.
• (ii) For example the electrical energy
  produced enhances peoples lives and smoke
  detectors have saved many peoples lives.
• (iii) Economic development for some countries
  through nuclear power.
• (iv) Reduced pollution by carbon dioxide,
  increased poluution from radioactive waste.
• (b) All by government / society.