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
Standard Form
Every GCSE physics paper normally has at least one question with a mark for the correct interpretation or expression of numbers in standard form. This is a basic skill that is taught as part of GCSE mathematics courses but it holds a great deal of power for scientific calculations that is rarely mentioned at this … Continue reading Standard Form
EM Waves: Uses and Dangers
Different EM waves are used for different applications, which you are expected to be able to recall and explain. We will go through some of these uses in this article, which is unavoidably long as there is a lot of information to cover. Your exam preparation should therefore involve making summary notes from the wealth … Continue reading EM Waves: Uses and Dangers
Electromagnetic Waves (overview)
We think of light as being special - but that's only because our eyes respond to it, allowing us to see the world around us. In fact, light is just one example of an electromagnetic wave. Other electromagnetic (EM for short) waves include infra-red, ultra-violet, radio and x-rays. The range of EM waves, known as … Continue reading Electromagnetic Waves (overview)
DC and AC Electricity Pt2: Seeing the Difference
We commonly use meters to make measurements in electric circuits but meters are relatively simple devices and if the property we are measuring changes over a short period of time then a meter will not show this clearly (if at all). But a different instrument, the oscilloscope, has the power to reveal such changes in … Continue reading DC and AC Electricity Pt2: Seeing the Difference
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
Speed of Water Waves
For hundreds of years, water waves have been used to understand wave behaviour in general. This is understandable given that water waves are a natural phenomenon that can also be created artificially and studied in the lab. On the simplest level, a stone thrown into the middle of a pond will create waves that extend … Continue reading Speed of Water Waves
Uses and Dangers of EM Waves
Electromagnetic (EM) waves are all similar; they are all transverse waves that travel at the same velocity and are created by the movement of electrons. But they are also different, not only in wavelength and frequency but also in how they are reflected, absorbed or transmitted by different materials. For example, the microwaves that your … Continue reading Uses and Dangers of EM Waves
The Electromagnetic Spectrum
Given that electromagnetic (EM) waves all have various things in common*, it makes sense to put them in order. We do this using their wavelength or frequency: it doesn't matter which one we choose because as wavelength increases, frequency decreases (and vice versa). Putting the different types of EM waves in order creates a spectrum … Continue reading The Electromagnetic Spectrum
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
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