Unit 8: Waves and Wave Properties
What actually travels when a wave moves: not the water or the rope itself, but a disturbance passed from particle to particle.
6 topics · 20 questions
Each topic is a path, not a menu: work down it in order and every question builds on the one above. Click any of them to watch the answer draw itself.
What a Wave Actually Is
- How it worksHow does a wave carry energy from place to place without carrying the medium along with it?
- Common mistakeWhy doesn't a floating duck get carried forward by a wave passing underneath it?
- Going furtherWhat happens to a wave's energy when its amplitude is doubled?
Your turn1 of 2
A stadium wave travels all the way around a packed arena, visibly sweeping past every section, yet no individual fan actually leaves their own seat to carry that wave around with them. Why does a stadium wave travel all the way around while no single fan ever leaves their seat?Transverse and Longitudinal Waves
- How it worksHow does a transverse wave move its medium perpendicular to the wave's direction while a longitudinal wave moves it back and forth along the same line?
- Worked exampleFind the wavelength of a longitudinal wave whose compressions are spaced 0.4 meters apart.
- Common mistakeWhy isn't sound a transverse wave the way a wave on a rope is?
Your turn1 of 2
Find the wavelength of a longitudinal wave whose compressions are spaced 13.94 meters apart.Wave Speed, Frequency, and Wavelength
- How it worksHow does the wave equation link speed, frequency, and wavelength into one relationship?
- Worked exampleFind the speed of a wave with a frequency of 5 Hz and a wavelength of 2 meters.
- Common mistakeWhy doesn't shaking a rope faster change the speed the wave travels down it?
- Going furtherWhat happens to a wave's wavelength when its frequency doubles but its speed stays fixed?
Your turn1 of 2
Find the speed of a wave with a frequency of 348.36 Hz and a wavelength of 13 meters.Wave Reflection and Superposition
- How it worksHow do two overlapping waves add together point by point to make one combined shape?
- Worked exampleFind the resulting displacement where a wave of amplitude 3 cm overlaps a wave of amplitude 2 cm at the same point.
- Common mistakeWhy don't two waves passing through each other destroy one another permanently?
Your turn1 of 2
Find the resulting displacement where a wave of amplitude 14.08 cm overlaps a wave of amplitude 13.16 cm at the same point and moment, both displacing the medium in the same direction.Standing Waves and Interference
- How it worksHow do two waves traveling in opposite directions combine into nodes that never move and antinodes that swing wide?
- Worked exampleFind the wavelength of the standing wave on a 1.2 meter string vibrating in its second harmonic.
- Common mistakeWhy isn't a standing wave actually standing still with no wave motion happening inside it?
- Going furtherWhat happens to the number of nodes on a string as it vibrates in higher and higher harmonics?
Your turn1 of 2
Find the wavelength of the standing wave on a 7.06 meter string, fixed at both ends, vibrating in its 6th harmonic.Diffraction
- How it worksHow does a wave bend around obstacles and spread out after passing through a narrow opening?
- Common mistakeWhy doesn't diffraction mean a wave is somehow leaking through a solid wall?
- Going furtherWhat happens to how much a wave diffracts as the gap it passes through gets narrower?
Your turn1 of 2
A person standing around the corner of a building, completely out of sight, can still be clearly heard talking, even though sound can't bend around a solid wall the way light passing around the same corner would be almost entirely blocked. Why can you hear someone talking around a corner even when you can't see them at all?