GCSE Triple ScienceHow Science Works

Mr. Iacovos Pilinas

American Academy Larnaca

Targets:

Dependent, Independent and control variables. Repeated measurements Valid data Reliable data Outlier data Line of best fit Scatter plot Line of best fit Gradient

Answer the question to find:

Independent variable: What do I change?

Dependent variable: What do I observe?

Control variable: What do I keep the same?

Try it out!

Measure the width of your bench!

Groups of two

3 min

Repeated measures

For every measurement you take:

- Repeat it for at least two times

- Find the average

- Record the average value for your measurement

Valid data

In a valid experiment all variables are kept constant apart from those being investigated

All systematic errors (=incorrectly calibrated instruments) have been eliminated

Random errors (=human misjudgment; limitations in the equipment) are reduced.

Reliable

Reliability refers to repeatability or consistency of results.

So always take repeated measurements!

Outlier data

Observations that lie “far” away from other values

It is up to the analyst to decide what will be considered “far”.

Scatter plot

A graph that relates the data between two variables:

Line of best fit

A line (straight or curve) on a scatter plot which can be drawn near the points to more clearly show the relation between two variables

Gradient of a graph

Give two examples using the relation V=IR