Working Scientifically

Question 1

What is a hazard?

Answer 1

Something that could potentially cause harm

Question 2

Name 2 safety procedures one should take when working with sulfuric acid

Answer 2

Wear gloves and safety goggles

Question 3

Name a safety procedure one should take when working with a Busen Burner

Answer 3

Put it on a heat proof mat (reduce risk of starting a fire)

Question 4

What do you use a hypothesis for?

Answer 4

To make a prediction

Question 5

What are investigations used for?

Answer 5

To see if there’s patterns or relationships between 2 variables

Question 6

Evidence needs to be _________, ________ and ______

Answer 6

Repeatable, Reproducible and Valid

Question 7

What is meant by repeatable?

Answer 7

If same person does an experiment using same method & equipment = get similar results

Question 8

What is meant by reproducible?

Answer 8

If someone else does experiment, or different method or equipment used = similar results

Question 9

What is meant by valid results?

Answer 9

• Both repeatable and reproducible AND answer original question
• Come from fair experiments

Question 10

Data that’s repeatable and reproducible is _____

Answer 10

reliable

Question 11

____ the Sample Size the Better

Answer 11

Bigger

Question 12

Why should a sample size be big (name 2 reasons)

Answer 12

• Sample should represent whole population
• Smaller samples = harder to spot anomalies

Question 13

Why do samples not include everyone? (name 2 reasons)

Answer 13

Would take too long and cost too much

Question 14

How do you get a fair test?

Answer 14

By controlling variables

Question 15

What is an independent variable?

Answer 15

Variable you change

Question 16

What is a dependent variable?

Answer 16

Variable you measure when you change independent variable

Question 17

What are control variables?

Answer 17

Variables you keep the same

Question 18

Measuring equipment needs to be _____ enough

Answer 18

sensitive

Question 19

What is meant by resolution?

Answer 19

Smallest change a measuring instrument can detect

Question 20

How can you calibrate equipment?

Answer 20

By measuring known value

e.g. placing a thermometer in melting ice to see whether it reads zero

Question 21

Data should be ____, _____, _____ and _____

Answer 21

Repeatable, Reproducible, Accurate and Precise

Question 22

What is meant by accurate?

Answer 22

Results are really close to true answer/value

Question 23

Why is counting bubbles not very accurate? (give 2 reasons)

Answer 23

∵ you might miss some bubbles or they might have different volumes

Question 24

What is more accurate than counting bubbles?

Answer 24

Measure vol. of gas using gas syringe

Question 25

How can you check the repeatability of your results?

Answer 25

By repeating readings to check results are similar

Question 26

How can you check the reproducibility of your results?

Answer 26

Take 2nd set of readings with another instrument or different observer

Question 27

What are precise results?

Answer 27

Data really close to mean of your repeated results i.e. not spread out

Question 28

How can you increase the precision of your results?

Answer 28

Alter experiment - use a smaller scale

Question 29

Why might results vary?

Answer 29

Due to random errors

Question 30

What are random errors?

Answer 30

Unpredictable differences

Question 31

Give an example of random error

Answer 31

e.g. human errors in measuring

Question 32

How can you reduce the effect of random errors on your results?

Answer 32

By repeat readings & finding the mean = make your results more precise + accurate (if there's no systematic error)

Question 33

What is a systematic error?

Answer 33

Measurement wrong by same amount every time

Question 34

How can you fix a systematic error?

Answer 34

Use a different technique or a different set of equipment

Question 35

What is a measurement error?

Answer 35

Difference between measured value and true value

Question 36

What is a zero error?

Answer 36

Systematic error caused by using equipment that isn't zeroed properly

Question 37

What are anomalies?

Answer 37

Results that don't fit trend/pattern, away from line of best fit

Question 38

What do headings in tables need to include?

Answer 38

Units

Question 39

When calculating mean, what do you do if you have an anomalous result?

Answer 39

Ignore it

Question 40

When doing calculations, what should you round your answer to?

Answer 40

Round the answer to lowest number of significant figures given

Question 41

When do you draw a bar chart?

Answer 41

Independent variable = categoric or discrete (e.g. data counted in chucks, no in-between value = shoe sizes)

Question 42

When do you draw a line graph?

Answer 42

Both variables = continuous data

Question 43

How do you calculate rates from a graph?

Answer 43

Question 44

How do you find the rate at any point on a curved graph?

Answer 44

By drawing a tangent i.e. straight line that touches a single point a curve

Question 45

What's the mutilple of unit for tera (T)?

Answer 45

10¹²

Question 46

What's the mutilple of unit for giga (G)?

Answer 46

10⁹

Question 47

What's the mutilple of unit for mega (M)?

Answer 47

million = 10⁶

Question 48

What's the mutilple of unit for kilo (k)?

Answer 48

1000

Question 49

What's the mutilple of unit for deci (d)?

Answer 49

0.1

Question 50

What's the mutilple of unit for centi (c)?

Answer 50

0.01

Question 51

What's the mutilple of unit for milli (m)?

Answer 51

0.001

Question 52

What's the mutilple of unit for micro (µ)?

Answer 52

10^-6

Question 53

What's the mutilple of unit for nano (n)?

Answer 53

10^-9

Question 54

What's a conversion factor?

Answer 54

no. of times the smaller unit goes into large unit

Question 55

How do you get from a bigger unit to smaller unit?

Answer 55

× by conversion factor

Question 56

How do you get from a smaller unit to bigger unit?

Answer 56

÷ by conversion factor

Question 57

What is uncertainty?

Answer 57

Interval within which the true value can be expected to lie

Question 58

What is uncertainty? (simplier definition)

Answer 58

Amount of error your measurements might have

Question 59

When you repeat a measurement you get a different figure due to random error, what does this mean?

Answer 59

Means each result has some uncertainty to it

Question 60

Why do measurements you make have uncertainty?

Answer 60

Due to limits in resolution

Question 61

Larger the range = ...

Answer 61

less precise your results are & more uncertainty

Question 62

How can you reduce uncertainty?

Answer 62

By measuring a greater amount

Question 63

How do you calculate uncertainty?

Answer 63

Question 64

Correlation ____ \_\_\_\_ mean Cause

Answer 64

DOES NOT

Question 65

Name 3 possible reasons for a correlation

Answer 65

* Chance * Linked by 3rd variable * Cause

Question 66

Suggest 3 general changes to a method to improve quality of results

Answer 66

* Increasing the no. of measurements you took * Changing the way you controlled a variable * Taking more measurements at narrower intervals (= more accurate result)

Question 67

Define Evidence

Answer 67

Data that's valid

Question 68

Define Hypothesis

Answer 68

Proposal intended to explain certain fact or observation

Question 69

Define Fair Test

Answer 69

In which only independent variable has allowed to affect the dependent variable

Question 70

Define Valid

Answer 70

* Free of error * Suitability of experiment to give accurate results

Question 71

Define Interval

Answer 71

Quantity between readings

Question 72

Define True value

Answer 72

Ideal measurement

Question 73

Define Data

Answer 73

Information = qualitative or quantitative

Question 74

Define Quantitative

Answer 74

Numbers

Question 75

Define Qualitative

Answer 75

Verbally done (words)

Question 76

Define Calibration

Answer 76

Marking a scale on a measuring instrument

Question 77

Define Prediction

Answer 77

State/suggest what will happen