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What causes a wave such as a water wave or a wave in a spring? Why do waves have crests and troughs? What causes a pulse? Does it also have crest and troughs?
Exploring the Science of Waves: Causes, Crests, and Troughs
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In summary, waves, such as water waves or waves in a spring, are caused by an imbalance of matter that results in a pulse of energy. This pulse can have crests and troughs depending on the initial conditions and can reflect differently depending on the type of end it encounters. Waves dissipate due to factors such as dispersion, damping, and spreading out of energy.
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jerromyjon
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Imbalance. As matter is perturbed from balance towards a crest it tends back towards balance but with momentum it overshoots into a trough and back towards balance, which constitutes a pulse.
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rootone
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Energy.
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jerromyjon
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That could be like a DC surge or an interference overlap... the questions are rather obscure in nature.
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Nugatory
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Sometimes there's no alternative to doing the math.
If we're considering water waves (just for definiteness), then gravity is acting to pull the high spot down... but as the water there is pulled down it has to displace the water underneath it, forcing it out to the sides, which displaces the water next to the peak, forcing it up and down. We can model this situation with a differential equation, the "wave equation" - google for it! - and solve it. Depending on the initial conditions, we'll find that any of the phenomena you mention will result.
(It would not be unusual to find an entire semester of an undergraduate physics program devoted to wave phenomena).
If we're considering water waves (just for definiteness), then gravity is acting to pull the high spot down... but as the water there is pulled down it has to displace the water underneath it, forcing it out to the sides, which displaces the water next to the peak, forcing it up and down. We can model this situation with a differential equation, the "wave equation" - google for it! - and solve it. Depending on the initial conditions, we'll find that any of the phenomena you mention will result.
(It would not be unusual to find an entire semester of an undergraduate physics program devoted to wave phenomena).
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member 529879
Okay I have one final question. Why does a wave dissipate? If you had a pulse traveling through a spring in space would it still dissipate?
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Nugatory
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Scheuerf said:
Waves dissipate for several reasons.
First, waves in many mediums are "dispersive", meaning that the speed of the wave varies with the frequency (water waves are dispersive, electromagnetic waves in a vacuum are not). A single nicely peaked wave like the one in the image you attached is actually a superposition of many different waves of different frequencies, so in a dispersive medium the peak will become ever shallower and wider as the different components move at different speeds until the peak becomes too small to notice.
Second, many mediums convert a little bit of energy to heat as the wave back and forth; this is called "damping". All springs have non-zero damping, so a wave traveling through a spring will gradually weaken and eventually disappear leaving only a slightly warmer spring.
Third, the wave only has so much energy, so if propagates in a way that tends to spread it out, it will get weaker. This is what happens with light from a point source like a distant star - the light spreads out in all directions, so the farther away we are from the star, the weaker the part of the wave that reaches us will be.
Related to Exploring the Science of Waves: Causes, Crests, and Troughs
1. What are waves and how are they formed?
Waves are disturbances that travel through a medium, such as water or air. They are formed when a source of energy, such as wind or an earthquake, causes a disturbance in the medium. This disturbance creates a ripple effect that travels outward from the source.
2. What causes waves to have crests and troughs?
The crests and troughs of a wave are caused by the alternating patterns of compression and expansion of the medium as the wave travels through it. When the medium is compressed, it creates a crest, and when it expands, it creates a trough.
3. How do waves transfer energy?
Waves transfer energy through the medium in which they are traveling. As the wave moves, it causes particles in the medium to vibrate, transferring the energy from one particle to the next. This energy transfer is what allows waves to travel long distances.
4. What factors affect the speed of a wave?
The speed of a wave is affected by the properties of the medium it is traveling through, such as density, elasticity, and temperature. It is also affected by the wavelength and frequency of the wave, with longer wavelengths and lower frequencies resulting in slower speeds.
5. How are waves used in everyday life and technology?
Waves have a variety of uses in everyday life and technology. For example, sound waves are used in communication systems, such as phones and radios, and in medical imaging technologies, like ultrasounds. Electromagnetic waves, including visible light, are used in technologies like TV and internet signals, and in medical treatments such as radiation therapy.
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