Definitions of Working Scientifically Skills

controlled variable

A variable that is kept constant (or changed in constant ways) during an investigation.

dependent variable

The factor in an experiment that changes in response to changes to the independent variable; conventionally plotted on the vertical (y) axis of a graph.

extrapolate/extrapolation

Occurs when the fitted model such as a line of best fit is used to make predictions using values that are outside the range of the original data upon which the fitted model was based.

first-hand (data)

Information or data which has been directly observed or measured.

independent variable

The variable that is deliberately changed, often through a series of pre-set values.

interpolate/interpolation

Making predictions between known data values. For example, working between 2 known points on a graph to predict a value in between these points.

qualitative

To use descriptive explanations involving features, characteristics or properties to identify important components. Data and information that is not numerical in nature.

quantitative

Data or components that can be expressed or measured numerically, including chemical formulae or numbers.

reliability

An extent to which repeated observations and/or measurements taken under identical circumstances will yield similar results.

risk (assessment)

The determination of quantitative or qualitative estimate of risk related to a well-defined situation and a recognised threat (also called hazard).

validity

The extent to which the processes and resultant data measure what was intended.

variable

A factor that can be changed, kept the same or measured in an investigation.

current

The rate of the flow of charges, measured in Amperes (A)

Power

The measure of how much energy is used per second, measured in Watts or Joules/s

Voltage

The amount of electrical potential energy that 'pushes' the charges around a circuit, measured in Volts (V)

Resistance

How much a substance impedes the flow of charge, measured in Ohms

Parallel Circuit

Type of circuit where there is more than one pathway for the charges to flow

Series Circuit

Type of circuit where there is only one path for the charges to flow

Rheostat

Another name for a variable resistor

Ammeter

Measures current in a series circuit

Voltmeter

Measures potential difference/voltage in a parallel circuit

Battery

Converts chemical potential energy to electrical potential energy, creating a direct current (DC)

Fuse

A device that burns out when the current gets too high in order to protect connected devices

Alternating Current (AC)

Type of current where the electrons oscillate back and forth

Direct Current (DC)

Type of current where the electrons only flow in one direction

Transformer Rectifier

Commonly known as a power pack, can transform voltages and rectify AC to DC

Efficiency

The ratio of the energy output to the energy input usually expressed as a percentage

Alternate Energy

energy derived from sources that do not use up natural resources or harm the environment

Electricity Formulas: Ohms Triangle

Total Resistance in Series Curcuits

Rt = R1 + R2 + R3

Total Current in Series Curcuits

The total current has to stay the same as it is the flow of electrons. I1=I2=I3 . . .

Total Voltage in Series Curcuits

There is a drop in potential across each resistor that adds together to equal the original voltage of the battery. Vt = V1 + V2 + V3

Total Resistance in Parallel Circuits

1/Rt = 1/R1 + 1/R2 + 1/R3
Invert to find the total resistance at the end

Total Current in Parallel Circuits

It = I1 + I2 + I3

Total Potential Difference in Parallel Circuits

Vt = V1 = V2 = V3