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)
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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
Electric Field & Electric Potential
It is tempting to regard the equations for electric fields and electric potentials as being separate things but they are so closely related that they are best viewed as different sides of the same coin. This is because electric field strength is the same as potential gradient. Or to put it another way, the electric … Continue reading Electric Field & Electric Potential
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
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
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