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
The Sand and the Swimming Pool
Here’s an interesting problem that is directly applicable to the behaviour of light. Suppose that you want to get from point A to point B, what is the fastest route? The most common answer is “in a straight line” but this isn’t always true. Let’s put our points A and B on a sandy beach … Continue reading The Sand and the Swimming Pool
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
DC and AC Electricity Pt1: Electron Movement
One of the most famous technological "wars" was the battle that raged almost 150 years ago between Thomas Edison's DC electricity and Nikola Tesla's AC electricity. For our purposes, we will put aside the stories of the two men (Edison was an inventor and businessman whereas Tesla was a scientist and idealist) and focus on … Continue reading DC and AC Electricity Pt1: Electron Movement
Quantum Game
If you want to play a fun game and (optionally) learn about the curious behaviour of light, then Quantum Game is for you! The nature of light has divided opinion in physics for literally thousands of years, from the time of Pythagoras and Aristotle in ancient Greece to the current day. In the seventeenth century, … Continue reading Quantum Game
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
Check your Knowledge
The ability to recall key facts and the relationships between those facts is an important part of learning in any context. As we reach the end of the two modules covering Waves and the Electromagnetic Spectrum it is important that you check how much you can remember of the content that has been covered. To … Continue reading Check your Knowledge
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
Observing Waves
Although human vision relies on visible light, we can't actually see light itself. Physicists have therefore modelled the behaviour of light using waves that can be seen, especially water waves. In the lab, we would be able to observe this using a ripple tank but you can currently experience this experiment from home using resources … Continue reading Observing Waves
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