Working Scientifically

Question 1

When evaluating science applications - 5 implications to consider

Answer 1

• personal
• social
• economic
• environmental
• ethical

Question 2

What’s an ethical issue

Answer 2

A problem where a choice has to be made concerning what is right and what is wrong

Question 3

How do scientific methods and theories develop over time?

Answer 3

new technology allowing new evidence to be collected and changing explanations as new evidence is found

Question 4

Why are models helpful (3)

Answer 4

• making scientific ideas easier to understand
• help in making predictions
• help in developing explanations

Question 5

Representational model

Answer 5

• use familiar objects to describe and explain observations

- e.g. using marbles to model water particles

Question 6

Spatial models

Answer 6

• represent things that are tiny/ enormous

Question 7

Descriptive models

Answer 7

• use words and ideas to help imagine something, or describe it simply
• chemical equations to represent reactions

Question 8

Mathematical models

Answer 8

• use maths to describe systems and make predations

- scientists use these to describe and predict movements of planets and stars

Question 9

computational model

Answer 9

• a type of mathematical model

- Met Office uses supercomputer used to predict weather

Question 10

Peer review - meaning

Answer 10

Research that is peer reviewed has been evaluated by other scientists who are experts in that area of science.

Question 11

What does peer review check (3)

Answer 11

Valid - does it measure what it says it does, was the method designed correctly and appropriately?

Original - has anyone else already carried out similar research, and has their work been credited? Are the results new?

Significant - are the findings of the research important?

Question 12

Models advantage

Answer 12

Models can help to investigate an idea without ethical or practical difficulties.

Question 13

International system of units - Sl

What and Why?

Answer 13

• scientists use internationally accepted names, symbols, definitions and units so that scientists everywhere can understand their work

Question 14

Hypothesis - what (3)

Answer 14

• explanation based on observations
• and backed up by scientific knowledge and creative thinking.
• Must be testable

Question 15

How scientists answer questions

Answer 15

1. Make an interesting observation or notice a problem to solve
2. Ask a scientific question
3. Develop a hypothesis
4. Make a predication based on hypothesis
5. Collect evidence to test prediction by doing an experiment and/or making observations and/or searching for data else where
6. Analyse the evidence
7. Review the evidence - does it support the hypothesis - if no back to (step 3)
8. Accept the hypothesis and develop it as an explanation or theory

Question 16

independent variable

Answer 16

Variable you deliberately change

Question 17

Dependent variable

Answer 17

Variable you measure for each change of the independent variable

Question 18

Control variables

Answer 18

Ones that make affect the outcome, as well as the indecent variable.
These variables are kept the same

Question 19

Continuous variable

Answer 19

Can have any value, and can be measured (e.g. time spent on social media)

Question 20

Discrete variable

Answer 20

Whole number values

E.g. number of texts

Question 21

Categoric variable

Answer 21

Values are described by labels

E.g. make and model of a phone

Question 22

Accuracy is what

Answer 22

How close a numerical result is to the true value

Question 23

Measuring temp. With a thermometer

- 3 things to do

Answer 23

• using thermometer carefully
• repeating measurements and calculating the mean
• repeating measurements with a different instruments, e.g. a temperature probe anbd checking that the readings are the same

Question 24

Anomalies

Answer 24

try to explain why the odd result is different - an odd result can be removed if there is a good reason to do so, eg if there is a measurement or recording error

Question 25

Precision ?

Answer 25

Precise measurements give similar results if you repeat the measurements - so spread of data set is small

Question 26

How to get precise data

Answer 26

- use a measuring instrument with high resolution - the resolution of a measuring instrument is the smallest change in the quantity that gives a change in the reading that you can see

Question 27

How should all results be recorded when using a measuring instrument

Answer 27

To same number of decimal places

Question 28

How to see which set of data is more precise?

Answer 28

Check the spreads - subtract smallest measurement from largest

Question 29

Can data be precise but not accurate

Answer 29

Yh

Question 30

Repeatable

Answer 30

Measurements are very similar when repeated by the same person or group, using the same equipment and method

Question 31

Reproducible

Answer 31

Measurements are very similar when repeated by a different person or group, using different equipment and/or methods

Question 32

If someone else repeats your investigation / | If you do same investigation with different equipment =

Answer 32

Reproducible

Question 33

Repeat several times using same method and equipment and get similar results, results are ?

Answer 33

Repeatable

Question 34

Table, which columns for independent variable, which for dependent , where units written ?

Answer 34

- IV in left column - DV in right column - write units in column headings, not next to each piece of data

Question 35

What chart/graph for categoric data?

Answer 35

Bar chart | Cat, dog, Guinea pig

Question 36

Chart/graph for continuous data

Answer 36

Line graph

Question 37

Variable on x + y axis

Answer 37

Independent, x | Dependent, y

Question 38

Scale of y axis =

Answer 38

- scale is even | - chart should be as big as possible

Question 39

Tell me about outliers - what it is - included in mean or no

Answer 39

- any value in a set of results that you judge its not part of the natural variation you expect - consider outliers carefully, and decide whether or not to include them when calculating mean

Question 40

Line of best fit (3) | - incl shape

Answer 40

- circle any outliers - decide whether the LOBF is a straight line or curve - draw line through middle of points - should be roughly same number of points above the line as there are below it

Question 41

2 parts of a scientific conclusion

Answer 41

- description of a pattern | - scientific explanation of the pattern, linked to the hypothesis

Question 42

Relationships between variables

Answer 42

- linear | - positive/ negative

Question 43

TO EVALUATE an investigation. Think about 2 questions:

Answer 43

- how to improve method | - what is the quality of the data

Question 44

Quality of data can be evaluated by considering (4)

Answer 44

Accuracy, precision, repeatability, reproducibility

Question 45

2 types of errors | Confidence in accuracy o results. Data cannot always be relied upon

Answer 45

Random error, systematic error

Question 46

Random error

Answer 46

Random errors are unpredictable and can be due to human error. eg in judging when to stop a timer, changes to em or e.g. changes in environmental conditions

Question 47

Action against random errors

Answer 47

- you cannot control the chase of random errors | - however, you can reduce their effect by repeating measurements and calculating a mean

Question 48

Systematic errors

Answer 48

Systematic errors cause results to differ from the true value by the same amount each time. These could be due to: - a fixed error in the measuring instrument, eg not being correctly zeroed (ammeter that doesn’t read zero when no current) - influence of the environment, eg allowing a reaction to take place at a hotter temperature - method of observation, eg not reading the volume of a liquid correctly using bottom of the meniscus

Question 49

Against a systematic error

Answer 49

- if you think you have a systematic error, repeat the measurements with a different piece of equipment - then compare the two sets of measurements

Question 50

Uncertainty definition

Answer 50

The interval within which the true value can be expected to lie, with a given level of confidence I.e. temperature is 65.5 degrees C +- 0.5 C with a confidence of 95 percent

Question 51

Uncertainties are due to

Answer 51

Measuring instrument

Question 52

If the smallest scale division is 1 degrees, you can estimate the uncertainty as

Answer 52

+- 0.5 degree

Question 53

Range and confidence in results

Answer 53

The range describes the difference between the highest and lowest repeat results. The smaller the range, the greater the confidence will be in the accuracy of the results.