We can define a wave as something that carries energy from one place to another without the transfer of physical matter. To understand this definition it is useful to think about two different ways of feeling heat. In a shower, heat is created by an energy exchange inside the storage tank or shower unit and … Continue reading Key Facts: Waves
Microphones and Loudspeakers
There is a great cross-over between two topics, waves and electricity, when we come to moving-coil microphones and loudspeakers. This pair of devices can be thought of as the sound-wave equivalent of motors and generators. Motors turn electrical energy into kinetic energy whereas generators turn kinetic energy into electrical energy. Similarly, microphones turn sound waves … Continue reading Microphones and Loudspeakers
Speed of Sound in an Iron Bar
Sound travels at different speeds in different materials. We often think only of sound moving through the air (a gas) but in fact it also moves through both liquids and solids. Note that there is a difference between sound moving through a liquid and waves that can be seen on the surface of a liquid. … Continue reading Speed of Sound in an Iron Bar
Representing Waves
Waves on water are very familiar, especially here in Jersey, but to analyse waves properly we need an instrument that offers suitable measurement features. The instrument that we use is called a Cathode Ray Oscilloscope (CRO). You have seen sound waves on a CRO screen in the lab and you can revisit this learning online … Continue reading Representing Waves
Sound: A Quick Recap
Sound is the most common example of a longitudinal wave (if you need a second example in an examination, mention seismic P waves from earthquakes). It is therefore important that you can describe and explain sound waves. This includes how the human ear works (in physics terms) and how microphones and loudspeakers link sound to … Continue reading Sound: A Quick Recap
Sound waves and sonic booms
When an object moves through the air, the noise it creates spreads out in all directions, moving away in waves that travel at the speed of sound. But what happens when the object is moving faster than the speed of sound? In this case, the sound waves that are trying to move ahead get overtaken … Continue reading Sound waves and sonic booms
Energy Stores and Transfers
Energy is the property of a system that enables it to do work. This is often stated bluntly as; “energy makes thing work”. There is a fundamental law in physics, which states that the total amount of energy in a system always remains constant. Energy cannot be created and it cannot be destroyed. Energy can, … Continue reading Energy Stores and Transfers
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