Key Words Flashcards
What’s a dependent variable?
In an experiment, what the effect or output is. What is measured.
What’s a hypothesis?
An idea or proposal to explain certain facts or observations. Based on observations.
What’s an independent variable?
In an experiment, what is changed and isn’t usually affected by the other variable.
What’s a control variable?
Factors which are kept the same in an experiment.
A variable that is kept constant prat least monitored to minimise its impact of the dependent variable.
Accuracy
How close a result is to the true value
Calibration
Establishing the relationship between scales on a measuring instrument and what the true value should be e.g. Placing a thermometer in melting I to see whether it reads zero to check it calibrated correctly.
Data
Information, either qualitative or quantitative, that has been collected.
Measurement error
The difference between a measured value and the true value.
Random error
The varying of results in an unpredictable way from one measurement to the next.
Random errors cannot be corrected but their eft can be reduced by carrying out repeats and calculating a mean.
Systematic error
Caused by things such as the environment, instruments used and methods of observation, these cause readings to differ from the true value by a consistent amount each time a measurement is made.
Zero error
Any indication that a measuring system gives a false readings hen the true value of a measured quantity is zero
E.g. The needle on an ammeter failing to return to zero when no current flows.
Anomalies
Values in a set of results that are judged to deviate from the normal or common order, for or rule.
Evidence
Data that has been shown to be valid.
Fair test
A test where only the independent variable has been allowed to affect the dependent variable. All other variables have been controlled.
Interval
The quantity between readings e.g. A set of a set of 10 readings equally spaced over a distance of 1 meter would give an interval of 10 cm
Precision
Measurements that aren’t spread far from the mean value.
Prediction
A statement suggesting what will happen in the future, based on observations, experience or a hypothesis.
Range
The maximum and minimum values of the independent or dependent variables, important in ensuring that any pattern is detected e.g. A range of distances may be “from 10 to 50 cm”.
Repeatable
If the investigation can b repeated by the same person using the same method and equipment and obtain the same result.
Reproducible
If the investigation can be repeated by another person or by using different equipment or techniques and they still obtain the same results.
Resolution
The smallest change in the quantity being measured off of a measuring instrument e.g. +/- 0.01
Sketch graph
A basic graph, not necessarily on a graph, that shows the general shape of the relationship between the two variables.
Points aren’t plotted and although axes are labelled they’d may not be scaled.
True value
The value that would be obtained in an ideal measurement with no errors.
Uncertainty
The interval within which the true value can be expected to lie with a given level of confidence or probability e.g. The temperature is 20’C +/- 2’C at a level of confidence of 95%.
