A-level Science: Experimental Techniques, Data Analysis, and Equipment

Syringe

An appropriate piece of equipment used for measuring small volumes.

Absolute uncertainty

It has a higher resolution and will therefore result in a lower percentage uncertainty.

Interpreting volumes

To work out uncertainty you must find the smallest increment of measurement on your measurement device and then divide it by two.

Precision

How close the agreement is between several measured values.

Accuracy

How close a reading is to the true value.

Quantitative observations

Numerical observations, for example, length or time.

Qualitative observations

The only value that should be changed throughout an experiment.

Dependent variable

This is the variable that is measured to determine the result of the experiment.

Control variable

Any values that affect the result of your experiment should be controlled or monitored.

Mean

The sum of all the values divided by the number of values in the data set.

Median

The middle value when the data is ranked.

Mode

The value that occurs most often in a data set.

Standard deviation

A measure of the average.

Anomaly

A result that deviates from what is standard or expected.

Evaluating data

Methods of evaluating data include checking for anomalies and assessing precision and accuracy.

Control experiment

A test conducted exactly the same as the test experiment, but with the factor causing the change removed.

Stop clock/watch

Used to measure time.

Thermometer or data logger

Used to measure temperature.

Indicator paper, indicator solution, data logger/pH metre

Used to measure pH.

Risk assessment

Identifying potential hazards and their consequences.

Reliable sources

Sources that are credible and free from bias.

Referencing

Citing sources by stating their surname and publication date.

Colorimeter

Measures light absorbance or light transmission of a substance.

Potometer

A piece of apparatus designed to measure water uptake in a leafy shoot.