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
Energy: the biggest “big idea”
Physics, let alone all the sciences put together, covers such a vast range of knowledge that it's useful to identify a small number of "big ideas" that link across a greater number of concepts. And energy is undoubtedly the biggest of these "big ideas". When it comes to revising energy, the breadth of its impact … Continue reading Energy: the biggest “big idea”
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
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
Light and Heat
It is obvious to say that hot objects emit (give off) both visible light (a glow) and heat (that we can feel but not actually see). This is true of bonfires, light-bulbs and even our Sun. The connection between heat and light is taken completely for granted in everyday life: the glow of a hot … Continue reading Light and Heat
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
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
Electromagnetic (EM) Waves
Electromagnetic (EM) waves are a family of different types of waves that have some specific properties in common; they all propagate (travel) at the same speedthey are all transverse wavesthey can all propagate through free space without the need for any medium The most common examples of EM wave are the various colours of visible … Continue reading Electromagnetic (EM) Waves
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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