fundamental basics of experiments

Question 1

describe validity

Answer 1

Validity relates to the experimental method and how appropriate it is in addressing the aim of the experiment:

does my experiment answer my aim? (otherwise why tf are you doing this)

Question 2

How do you improve validity?

Answer 2

Validity can be improved by improving experimental apparatus and process, making your experiment better answer the aim.

Question 3

What is accuracy?

Answer 3

Accuracy is how close your experimental data aligns with the expected avlue

Question 4

How do you improve accuracy?

Answer 4

The accuracy can be improved through the experimental method if each single measurement is made more accurate, e.g. through the choice of equipment. Implementing a method that reduces systematic errors will improve accuracy.

Question 5

Accuracy is affected by?

Answer 5

systematic error

Question 6

Reliability is affected by?

Answer 6

random error

Question 7

Describe the shooting range analogy

Answer 7

You can be: reliably accurate, reliably inaccurate,
unreliably accurate and unreliably inaccurate.

Question 8

What is reliability?

Answer 8

Reliability is about how close repeated results are to each other.

A measurement is reliable if you repeat it and get the same or a similar answer over and over again, and an experiment is reliable if it gives the same result when you repeat the entire experiment.

Question 9

Describe precision

Answer 9

precision is the measuring capability of measuring equipment: e.g a clock is 1 second max precision, a stopwatch is max 0.01 second precision.

Question 10

describe systematic error

Answer 10

a systematic error reduces accuracy, and is consistent in direction and amount

Systematic errors will shift measurements from their true value by the same amount or fraction and in the same direction all the time. These do not affect the reliability (since they’re always the same) but affect accuracy.

Question 11

describe random error

Answer 11

an error that is random in direction and amount

Question 12

what is scale error?

Answer 12

scale weight is different by a constnat percentage

SYSTEMATIC ERROR

Question 13

what is parallax error?

Answer 13

a systematic error in the reading of data

Question 14

what is zero error?

Answer 14

If a piece of equipment has an offset (e.g. a mass balance shows a reading that is not zero when there is nothing on it), all measurements will be offset by the same amount.

Question 15

is reaction time random or systematic error?

Answer 15

random error

Question 16

define a controlled variable

Answer 16

a variable that is constant throughout all iterations of an experiment and its trials

Question 17

define an independent variable

Answer 17

a variable that is changed in order to determine results and affect the dependent variable

Question 18

define a dependent variable

Answer 18

a dependent variable is basically your result, it is a variable that arises from the testing of your independent variable and controlled variables

Question 19

what is a hypothesis

Answer 19

a possible explanation that needs to be rigorously tested by experimental evidence

Question 20

The experimental uncertainty in a measurement of any particular quantity is best described
as

Answer 20

A quantitative estimate of the doubt associated with the measurement

(measuring device has an uncertainty of +- half of its smallest measure, aka a ruler with 1cm intervals has a +- 0.5cm uncertainty)