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
Paper vs Plastic Straws
The one fundamental fact that links all discussions about trying to do the best for planet Earth is things are rarely as simple as we would wish. This warning applies not only to discussions but also, more seriously, to actions as well. An initiative that is being rolled-out in the UK and many other countries … Continue reading Paper vs Plastic Straws
Aircraft take-off velocity
Three years ago I explained how to use photographs to estimate the speed of a passing car. You can read that article at https://physbang.com/2020/08/02/keep-the-cogs-turning/. Now it is time to use a similar technique to answer a more challenging question: what is the take-off velocity of a passenger jet? Of course, the answer could be found … Continue reading Aircraft take-off velocity
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?
Shapes of Shadows
First a correction: this post is really about the shapes of the bright patches between shadows but "shapes of shadows" sounds much better so please excuse my decision to go for artistic alliteration! If you have ever walked under some leafy trees on a bright summer's day, with the sun high in the sky, you … Continue reading Shapes of Shadows
About physbang
physbang.com started life in 2018 to support students studying GCSE Physics, whether as a separate subject (Edexcel syllabus) or as part of a combined-sciences, double-award course (AQA Trilogy syllabus). A few items have also been posted for the benefit of keen Y9 students and others have been published "just for fun". With effect from Summer … Continue reading About physbang
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
Half-term Revision: Forces and Paper 2
Last year (2022) I created two sets of questions that are designed to test your knowledge of the Forces and their Interactions topic for Paper 2 of AQA Trilogy Physics. One test is for Higher Tier and can be accessed by clicking here; the other is for Foundation Tier and can be accessed here. Both … Continue reading Half-term Revision: Forces and Paper 2
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
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