Classification of Stars
The obvious way to classify stars is by their appearance; how bright they are and their colour. In both cases, we are referring to properties judged using the human eye from the location of planet Earth. Sadly, our eyes are not a good judge of colour (equal amounts of red and green light are perceived as the colour yellow) and…
Read moreElectricity: models and theories
Physics can get complicated at times and when it does, we use models to simplify things. The models aren’t wrong: in fact they work remarkably well, but they aren’t complete. Electricity provides probably the best examples of this state of affairs. Models normally start at the level of “electrons as buckets carrying energy” and include the idea that electricity flows…
Read moreA-level guide to astronomical telescopes
The first section of the Astrophysics module for AQA A-level Physics is all about telescopes. This post is a brief summary of that section’s key learning points. Telescopes aren’t used simply to make astronomical objects “bigger” or to get a “closer” view. It is true that nearby objects, such as our moon and other bodies inside the Solar System, do…
Read moreRadiation detectors
The first device that comes to mind as a radiation detector (for use in schools) is probably the Geiger-Mueller (GM) tube. Although GM tubes can be used to detect all three types of ionising nuclear radiation (alpha, beta and gamma) they are subject to some important limitations. These shortcomings will be discussed below, together with other techniques for detecting particular…
Read moreDoes radiation make things radioactive?
The short answer is “no” but the devil is always in the detail. Firstly, “radiation” here applies specifically to ionising radiation; alpha particles, beta particles and gamma photons. In particular, we are excluding non-ionising nuclear radiation in the form of neutrons, which definitely can turn previously stable nuclei into radioactive materials. This effect is a significant contributor to the clean-up…
Read moreSomething went wrong. Please refresh the page and/or try again.
Follow My Blog
Get new content delivered directly to your inbox.
Mr Tarrant's physbang 'blog 