The earliest ways of generating light all involved heat, whether that meant setting a fire, burning a pitch torch, lighting a wax candle or heating a mantle using a gas flame. When electricity arrived, thoughts turned from creating light by chemical means to the possibility of using an electric current. Initial approaches still involved the … Continue reading Discharge and Fluorescent lighting
Experimental Errors (part 2)
The previous post (Experimental Errors, https://physbang.com/2023/11/12/experimental-errors/) ended with an invitation to "consider whether there are any other, previously unidentified, sources of uncertainty" in the method used to derive the specific heat capacity of an iron block. As it happens, there are (at least) three possibilities that weren't covered in the original article. Firstly, there is … Continue reading Experimental Errors (part 2)
Experimental errors
Experiments are often used to confirm (or, more usefully, refute) particular ideas but their impact is limited by measurement errors that can compromise the results. The obvious answer is to reduce the uncertainties as much as possible but what do you do if this causes the result to move further away from the expected value? … Continue reading Experimental errors
Electron deflection tube
It is common to think of the electron deflection tube as a device that demonstrates the behaviour of electrons within an electric field but in fact there are two electric fields at work. The first field accelerates electrons that are released by a heated coil then the second field deflects those electrons as they travel … Continue reading Electron deflection tube
Radiation and Altitude
The discovery of radioactive rocks was unexpected but when physicists attempted to discover how far the new “penetrating rays” could reach, they were in for an even bigger surprise. Henri Becquerel’s discovery that uranium salts emit penetrating radiation was one of science’s great “accidents”. Uranium was first identified in 1789 but it was a century … Continue reading Radiation and Altitude
What is mass?
Mass is a tricky concept. We all think we know what it is: it's what you measure when you put something on weighing scales or a digital balance. Alternatively, you could say mass is the property of an object that resists changes to its movement. In other words, an object with lots of mass is … Continue reading What is mass?
Key Facts: (Electro)Magnetism
With only the final Physics paper left to be sat in the this year's AQA Trilogy exams, you should now be giving your revision a final push. Magnetism and electromagnetism is a fairly compact stand-alone topic and is the ideal candidate for a quick refresher. The knowledge you need can be divided into six areas … Continue reading Key Facts: (Electro)Magnetism
Key Facts: Electromagnetic Waves
Having previously covered waves in general (https://physbang.com/2023/04/13/key-facts-waves/) it is now time to look at electromagnetic waves in particular as this is a topic in its own right. Electromagnetic waves are created by the movement of electrons in different situations. The electrons can be moving in an electric circuit, to produce or receive radio waves, or … Continue reading Key Facts: Electromagnetic Waves
Key Facts: Electric circuits
Electricity is one of the forms of energy transfer so it is not surprising that the definition of the volt (the unit for measuring potential difference) is the energy carried per unit charge. In symbols, where Q is the symbol for charge, this relationship is written as; V = E / Q It is important … Continue reading Key Facts: Electric circuits
Key Facts: Renewable Energy
Examination boards are very keen on asking students to apply their knowledge to real-world situations. One of the most important issues in the world today is climate change and one of the most important ways to address this is by switching from non-renewable energy sources to renewables. BP, which has long been thought of as … Continue reading Key Facts: Renewable Energy
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