Science - Non-science

Question 1

Uncertainty

Answer 1

A margin around a measured value which all other repeated measurement should fall around and is a measure of precision

Question 2

Measurement Uncertainty

Answer 2

The margin for how close either side a marked measurement is to its actual value
- for analogy instruments it is half the smallest scale
- for digital instruments it is 1 unit in the least significant digit

Question 3

Uncertainty in the mean

Answer 3

How close the average of the data scores collected are to the true value and is a measure of the random errors or precision
- Max value - min value/2
- Recorded to 1 sig fig
- Between measurement uncertainty and UITM choose the biggest ne

Question 4

Absolute uncertainty

Answer 4

The measure of uncertainty in units as a independent value from the true value

Question 5

Relative Uncertainty

Answer 5

The measure of uncertainty as a percentage of the true value
- Absolute uncertainty/measured value * 100

Question 6

Error

Answer 6

The difference between the measured value and the actual value and is a measure of accuracy

Question 7

Adding and subtracting uncertainty

Answer 7

Always ADD the ABSOLUTE uncertainties

Question 8

Multiplying and Dividing Uncertainty

Answer 8

Always ADD the RELATIVE uncertainties

Question 9

Random Error

Answer 9

Errors that are spontaneous and chance events that cause the measured values to be deviate randomly from the true value and is caused by human error or changing external conditions.
Measure of precision

Question 10

Systematic error

Answer 10

Errors that occur repeatedly in the same spot and are to do with the measurement device or methodology or external conditions
Measure of accuracy

Question 11

Reliability

Answer 11

Reliability is how trustworthy a value is as a result of its precision or proximity to other values

Question 12

Validity

Answer 12

Validity is how trustworthy a value is as a result of its accuracy of its proximity to the true value and to the extent of which it measures what was intended.

Question 13

Accuracy

Answer 13

How close a measured value is to the true value

Question 14

Precision

Answer 14

How close a measured value is to other repeated measured values

Question 15

Vernier callipers

Answer 15

A measuring device with two scales that measures the dimensions of objects
- To find measurement take the the the increment on the large scale just before the 0 of the small scale
- find the number of increments on the small scale that it takes to line up the large scale
- the first measurement plus the second is the actual measurement

Question 16

SI Units

Answer 16

Standardized units for each type of measurement
- Distance: m
- Mass: Kg
- Time: s
- Electric current: A (Ampere)
- Temperature: K (Kelvin)
- Amount of Substance: mol
- Luminous Intensity: cd (candela)

Question 17

Significant figures

Answer 17

Essentially the number of numbers in a measurement and how many shows precision of measurement
- the last digit is an estimate
- the more sig fig - the more precise

Question 18

Sig Fig Rules

Answer 18

1. Non - zero figures are always significant
   
   • 12 and 18.98
2. All FINAL zeros AFTER decimal point are significant
   - 19.0 and 267.907
3. Zeros between two other significant figures are significant
   - 109 and 10.05
4. Zeros used for spacing significant numbers from either side of the decimal point are insignificant
   - 0.00004 and 129 000
5. Always put a zero before decimal if no other sig figs
   - 0.09 and 0.78

Question 19

Calculating with Sig figs

Answer 19

If adding or subtracting, the number is rounded to the least amount of DECIMAL PLACES that were in the two numbers
- 12.23 + 3.6 = 15.8

If Multiply or dividing, the number is rounded to the number of SIG FIGS that were in the least precise number (one with least sig figs)
- 4.05 * 10 = 40

Question 20

Absolute error

Answer 20

Measured value - accepted value

Question 21

Relative error

Answer 21

Absolute error/accepted value * 100

Question 22

Absolute variation

Answer 22

Measured value - Accapted value

Question 23

Relative Variation

Answer 23

Absolute variation/ Average of measured and accepted value * 100

Question 24

Variation

Answer 24

A deviation of the measured value from the accepted value, but it is not know that the are the same substance that is being tested for.

Question 25

Measurement

Answer 25

It the best estimate + or - the absolute uncertainty. Basically communicated that it lies closest to the estimate could could be anywhere in that range.

Question 26

Graphing

Answer 26

Used to convey relationships between things
Conventions:
- Error bars - use the highest uncertainty for each value and do vertical and horizontal
- line of best fit
- Compare systematic and random errors
- Display the equation of the line - y = mx +c
- Display R2 value
- Draw Min and Max lines
- Analyse the Uncertainty in the slope
- Analyse the Uncertainty in the c intercept

Question 27

R2 Value

Answer 27

Shows how close the values are to the line of best fit, thus showing the precision
- the closer to 1, the closer the fit

Question 28

Min and Max lines

Answer 28

Lines with the smallest gradient and largest gradient connecting the first and last error boxes.

Question 29

Uncertainty in the slope

Answer 29

Max Gradient - Min Gradient / 2

Question 30

Uncertainty in the y intercept

Answer 30

Max y-intercept -min y-intercept / 2

Question 31

Modifications

Answer 31

Modifications can be made to experiments to increase their precision and accuracy. the 3 types are:
1. Refine - the elimination or systematic and random error and reduction
2. Redirect - Test different subjects are variables relating to the experiment
3. Extend - test for more variables or at more increments

Question 32

Mistake

Answer 32

Not scientific, but refers to doing something inaccurate but with knowledge of how to do it accurately though carelessness
If a mistake is made - repeat the trial

Question 33

Limitations

Answer 33

Characteristics of the methodology that hinder the collection and interpretation of data

Question 34

Error vs Uncertainty

Answer 34

Systematic error dictates ACCURACY
Random error and uncertainty dictates PRECISION

Question 35

Reliability vs Validity

Answer 35

Reliability is dictated by PRECISION
Validity is dictated by ACCURACY

Question 36

Trends

Answer 36

The general direction of change in a variable

Question 37

Patterns

Answer 37

Data that repeats in a predictable way

Question 38

Relationships

Answer 38

Two or more data that is interdependent upon the other in direct or inverse proportion