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
Thermal Equilibrium
Any object that has a constant temperature is in a state of thermal equilibrium. This means the rate at which energy is transferred to the object is exactly equal to the rate at which energy is transferred from the object. In the context of electromagnetic radiation, we can state that the rate at which the … Continue reading Thermal Equilibrium
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
EMS Short Study Course
NASA has created an excellent self-contained short study course that covers the electromagnetic spectrum (EMS) from an astronomy perspective. This resource therefore has double value for GCSE Physics as it supports learning across the topics of both waves and space. The course comprises four introductory sections, eight units on parts of the electromagnetic spectrum and … Continue reading EMS Short Study Course
Future Impossible
Bell Labs has created a fantastic series of four short videos that I highly recommend. Coming from a team that is now part of Nokia, these videos focus on leading-edge information communication technologies but they do this in an extremely accessible way that shows the parts played by physicists in bringing industrial visions to life. … Continue reading Future Impossible
Using the EMS to Observe Earth
When we look down on the Earth from an aircraft, we are observing the surface of the planet using visible light in a qualitative way - which means that we are simply sensing (seeing) rather than measuring the amount of light reflected. By using instrumentation, we can extract much more meaning from our observations by … Continue reading Using the EMS to Observe Earth
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
Mr Tarrant's physbang 'blog 