How does the nucleus of an atom stay together? Why don’t the positively-charged protons repel each other and cause the nucleus to disintegrate? The early models of the atom imagined solid spheres, perhaps with different sizes, shapes or “colours” distinguishing one type of atom from another. Then came J J Thomson’s discovery of the electron … Continue reading Hideki Yukawa and Meson Theory
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
Balloon on the Moon
Imagine that you could take a helium-filled balloon to the moon. If you stood on the lunar surface, holding the ribbon tied to the bottom of the balloon, what would you expect to happen when it was released? We'll assume that the balloon doesn't burst and I'll give you four possible outcomes; The balloon rises … Continue reading Balloon on the Moon
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?
Revision 2022: The Final Straight
With Biology and Chemistry finished, it's all systems go in the final phase of science revision for the second Physics paper later this week (Thursday 23rd June). As was the case for Paper 1, I have created an index page of links to relevant physbang content using the Advanced Information provided by AQA. The index … Continue reading Revision 2022: The Final Straight
Electric Motors
Having covered Fleming's Left-Hand Rule previously, we will now apply its general principles to the specific application of an electric motor. In particular, we will look at how the sideways motion due to a linear force, as predicted in Fleming's Left-Hand Rule, can be used to produce continuous rotation. We will be focusing on a … Continue reading Electric Motors
Drawing Magnetic Fields
The shape of the magnetic field around a bar magnet should be familiar to you as it has been covered in detail in a previous article, which you can read here. But rather than just knowing this shape, it is important that you can describe how to investigate it. There are two versions of this … Continue reading Drawing Magnetic Fields
Permanent and Induced Magnetism
There is a separate article that explains magnetic fields and forces so this article focuses on magnetic materials and the difference between permanent and induced magnets. There are naturally occuring rocks that are capable of being magnetised (magnetite) and others that are already magnetised (lodestone). The important ingredient in both of these rocks is iron … Continue reading Permanent and Induced Magnetism
Contact and Non-Contact Forces
It is surprisingly hard to say what a force really is but on a simple level we say that forces are either pushes or pulls. It would be better to label "pulls" as forces of attraction and "pushes" as forces of repulsion. Some forces have their effect when objects are in contact whereas others allow … Continue reading Contact and Non-Contact Forces
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
Mr Tarrant's physbang 'blog 