Determining a spring toy’s jump height is a useful exercise in the application of physics, not only in terms of this specific example but also in highlighting contrasting approaches to answering any sort of physics question. As is so often the case, there are two possible starting points; the first is theoretical whereas the second … Continue reading How high does a spring toy jump?
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
Why does hot air rise?
Easy question! It's because hot air is less dense than cold air. Except that things aren't really this simple. How does hot air know its own density and the density of the cold air that surrounds it? For that matter, how does hot air know which way is up? You might say that hot air … Continue reading Why does hot air rise?
Changes of State
Despite having previously examined a phase-change diagram in detail (here) I haven't yet covered the particle model and how it links to different states of matter. So that topic, which is relevant for both chemistry and physics, is the focus of this article. First let's clarify the terminology... we will be confining ourselves to the … Continue reading Changes of State
Slowing and Stopping
To conclude the recent series of posts related to different aspects of motion, we will now look at a real-world application of these ideas: in particular, the physics of slowing and stopping a road vehicle. An earlier post (from 2019) covered the two components of a vehicle’s overall stopping distance so I won’t repeat that … Continue reading Slowing and Stopping
Kinetic Theory
Scientific theories are constructs (models) that we use to explain our observations. They are different from scientific laws, which are rules that have to be obeyed and which can be applied across a wide variety of situations. The best known example is the Big Bang Theory but we'll be looking at a theory that relates … Continue reading Kinetic Theory
Absolute Zero
Where does the idea of "absolute zero" come from? In part it stems from a need to avoid negative temperatures but a better explanation can be found by thinking about the kinetic theory of gases. When a gas is heated, its particles gain kinetic energy. This in turn means that the particles have a higher … Continue reading Absolute Zero
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