The Required Practical Assessment

Oh noes!

Newton's Second Law

Force equals mass times acceleration (F=ma)

Force (N)

A push or pull that can cause an object to accelerate

Mass (kg)

A measure of the amount of matter in an object

Acceleration (m/s²)

The rate of change of velocity

Data Logger

Electronic device used to automatically record measurements over time

Photogate (Light Gate)

Sensor that uses a light beam to measure the time an object takes to pass through it

Flag width

The length of the object passing through the photogate

Weight (N)

The force of gravity acting on an object

Independent variable (F=ma - force)

The force applied to the trolley (changed by hanging masses)

Independent variable (F=ma - mass)

The mass of the trolley (changed by adding masses)

Dependent variable (F=ma)

Acceleration of the trolley

Control variables (F=ma - constant mass)

The total mass of the system (trolley + hanging masses) should remain constant when changing the accelerating force

Control variables (F=ma - constant force)

The accelerating force (hanging mass) should remain constant when changing the mass of the trolley

Friction

A force that opposes motion between surfaces in contact

Air resistance

A force that opposes the motion of objects through the air

Graph of Force vs Acceleration

A straight line through the origin if mass is constant

Gradient of Force vs Acceleration graph

Represents the mass of the object (Force/acceleration = mass)

Hooke's Law

The extension of a spring is directly proportional to the force applied to it

Extension (m)

The increase in length of a spring from its original length when a force is applied

Force (N) (Hooke's Law)

The weight applied to the spring

**Spring constant (k

N/m)**

Limit of proportionality (Hooke's Law)

The point beyond which the spring no longer obeys Hooke's law

Original length (Hooke's Law)

The length of the spring with no force applied

Independent variable (Hooke's Law)

The force applied to the spring

Dependent variable (Hooke's Law)

The extension of the spring

Graph of Force vs Extension (Hooke's Law)

A straight line through the origin if Hooke's Law is obeyed

Gradient of Force vs Extension graph (Hooke's Law)

Represents the spring constant (k)

Infrared radiation

Electromagnetic radiation emitted by all objects due to their temperature

Leslie cube

A hollow metal cube with different surface finishes used to compare infrared emission

Matte black surface (IR)

A surface that is a good emitter and absorber of infrared radiation

Shiny surface (IR)

A surface that is a poor emitter and absorber of infrared radiation

Infrared thermometer

A device used to detect and measure the intensity of infrared radiation

Emission (IR)

The release of infrared radiation from a surface

Absorption (IR)

The taking in of infrared radiation by a surface

Independent variable (Leslie cube)

The type of surface on the Leslie cube

Dependent variable (Leslie cube)

The amount of infrared radiation emitted (measured by the thermometer)

Control variables (Leslie cube)

The temperature of the water inside the cube

Ripple tank

A shallow tank of water used to demonstrate wave properties

Oscillator (ripple tank)

A device that creates waves in the ripple tank

Wavelength (λ)

The distance between two successive crests or troughs of a wave

Frequency (f)

The number of waves passing a point per second

Wave speed (v)

The speed at which a wave travels (v = fλ)

Strobe light (ripple tank)

A flashing light used to make the waves appear stationary for easier measurement

Magnification (ripple tank)

The factor by which the image of the waves on the screen is larger than the actual waves

Independent variable (ripple tank)

Typically the frequency of the oscillator

Dependent variable (ripple tank)

Typically the wavelength of the water waves

Control variables (ripple tank)

The depth of the water in the tank

Signal generator (waves on string)

An electronic device that produces a signal of a specific frequency

Vibration generator (waves on string)

A device that vibrates a string at a controlled frequency

Transverse wave

A wave where the oscillations are perpendicular to the direction of energy transfer

Standing wave (waves on string)

A stationary wave pattern formed by the superposition of two waves travelling in opposite directions

Nodes (waves on string)

Points on a standing wave with zero amplitude

Antinodes (waves on string)

Points on a standing wave with maximum amplitude

Wavelength (standing wave)

Can be determined by measuring the length of loops in a standing wave

Independent variable (waves on string)

Typically the frequency of the signal generator

Dependent variable (waves on string)

Typically the wavelength of the standing wave

Control variables (waves on string)

The tension in the string (maintained by the mass at the end)

Reaction time

The time taken for a person to respond to a stimulus

Stimulus (reaction time)

A change in the environment that causes a response

Independent variable (reaction time)

The factor being investigated (e.g.

Dependent variable (reaction time)

The time taken to react to the stimulus

Control variables (reaction time)

Factors kept constant during the experiment (e.g.

Mean

The average of a set of measurements