Transverse Pulses & Waves: Evidence and Measurement

≈ 30 min

Evidence and Measurement

Connect the claim to observable evidence and state what uncertainty or limitation remains.

This extension applies that lens specifically to Transverse Pulses & Waves.

From a pulse to a wave

Flick one end of a stretched rope once and a single hump travels along it - that is a pulse. Keep shaking the end up and down steadily and you send a continuous train of pulses: a wave.

In a transverse wave the particles of the medium move perpendicular to the direction the wave travels. Each bit of rope only moves up and down, yet the shape moves sideways along the rope. The wave carries energy from one place to another without carrying the medium along with it.

The vocabulary of a wave

Amplitude ( $A$ ): the maximum displacement from the rest position. Bigger amplitude means more energy.
Wavelength ( $\lambda$ ): the distance of one complete wave - for example crest to next crest.
Period ( $T$ ): the time for one complete wave to pass a point, in seconds.
Frequency ( $f$ ): the number of complete waves per second, in hertz ( $\text{Hz}$ ).

Period and frequency are reciprocals:

f = \frac{1}{T} \qquad T = \frac{1}{f}

The speed of the wave links these together:

v = f\lambda

Physics: Motion, Waves & Electricity — Evidence and Measurement: In a transverse wave on a rope, how do the particles of the rope move relative to the direction the wave travels?

In the same direction as the wave

Perpendicular (at right angles) to the direction of the wave

In circles that grow larger over time

They do not move at all

Physics: Motion, Waves & Electricity — Evidence and Measurement: A water wave has a frequency of $4\,\text{Hz}$ and a wavelength of $0.5\,\text{m}$ . Calculate the speed of the wave in $\text{m/s}$ .

Physics: Motion, Waves & Electricity — Evidence and Measurement: A wave has a period of $0.25\,\text{s}$ and travels at $8\,\text{m/s}$ . Calculate its wavelength in metres.

Name the original topic being extended by this evidence and measurement lesson.

Which statement is the best evidence-led starting point for Transverse Pulses & Waves: Evidence and Measurement?

From a pulse to a wave Flick one end of a stretched rope once and a single hump travels along it - that is a pulse. Keep shaking the end up and down steadily and you send a continuous train of pulses: a wave. In a transverse wave the particles of the medium move perpendicular to the direction the wave travels. Each bit of rope only moves up

Vectors, Scalars & Motion in One Dimension

Electrostatics & Electric Circuits

A conclusion needs no observations, calculations or stated assumptions.