The Eskimos have hundreds of words for snow, or so they say, but what about ice Think ice is simple? Think again!
Yearly Archives: 2024
Why call them ‘holes’?
Black holes are regions with huge density, but why are they called ‘holes’? If I were baking a cake and it did not rise evenly, and a region in the cake was left far denser than the regions around it, I certainly would not refer to that dense region as a hole. Read this post to learn why ‘holes’ is an appropriate name for them after all.
Bye bye Patreon, bye bye Discord…
While I was redesigning my website (i.e. procrastinating from doing my marking) I noticed that it was possible to make certain blog posts that could only be seen to paying subscribers. I also noticed that it was possible to make parts of pages visible only to paying subscribers too. WordPress, who hosts my website, had some easy-to-use tools to make subscription work well.
Five questions A-Level physics does not answer
Students often choose to study A-Level Physics because they want to understand how the universe works. GCSE Physics has lots of gaps, but surely Advanced Level Physics will have the answers? Here are five intriguing mysteries that A-Level Physics does not answer.
Lamenting the loss of the sound of silence
I find it difficult to focus my attention on a single voice and hear what someone is saying to me if there is any background noise. Years ago I had my hearing tested and it was fine, it wasn’t a hearing issue. It is just something about the way my brain processes sound. For yearsContinueContinue reading “Lamenting the loss of the sound of silence”
The fascinating etymology of the word ‘diode’
Diode = two way… what an odd name for a component that allows current to flow just one way. Where did this name come from? I’ll explain all in this blog post.
Internal resistance and delivering the maximum power to a load resistor
I was teaching this on Friday but ran out of time to go through the calculus with my class, so here is a quick(ish) video about why you get the maximum power delivered when you match the load resistance to the internal resistance. Hopefully you find it useful! https://youtu.be/nEY3OsCPZtU If there’s anything you need helpContinueContinue reading “Internal resistance and delivering the maximum power to a load resistor”
A Level revision timetable!
I’ve written a spreadsheet that creates a revision timetable automatically – just plug in the topics and off you go. It includes interleaving and repetition to promote long term retrieval. Here’s a screenshot (the colours are for broad topics): This is available to enrolled A Level tutees, and there’s a GCSE version available to enrolledContinueContinue reading “A Level revision timetable!”
Looking inside the HP 9820A calculator
I was very kindly and generously gifted a Hewlett-Packard HP 9820A calculator by a good friend and ex-colleague. Unfortunately, the thing does not work, but I will try to get it working when I find the time between other things I have to do. The HP 9820A was the world’s first calculator that used anContinueContinue reading “Looking inside the HP 9820A calculator”
More fun with op amps: differentiation
Yes, I finally managed to get an op amp to differentiate an input potential that varies over time. The top trace is the input potential. The bottom trace is the output from the op amp, showing the first derivative of the input. Huzzah! I connected the differentiator circuit to a sinusoidal input potential, and afterContinueContinue reading “More fun with op amps: differentiation”
Physics with Keith 