Electromagnetic (EM) waves are generated by the movement of electrons. In an electric circuit, visible light can be generated when electrons (a current) move through a lamp. Electric circuits can also generate infra-red waves (TV remote controls), microwaves (ovens), x-rays (medical scanners) and radio waves (aircraft ground-to-air communications). These different types of EM waves have … Continue reading Properties of EM Waves
Energy Budget
It is well known that darker surfaces heat up faster than lighter surfaces and reach a higher maximum temperature. But why? When the maximum temperature is achieved, there is a state of thermal equilibrium that is is due to a balance between the rates at which (new) energy is being absorbed and (previously) stored energy … Continue reading Energy Budget
EM Waves: Uses and Dangers
Different EM waves are used for different applications, which you are expected to be able to recall and explain. We will go through some of these uses in this article, which is unavoidably long as there is a lot of information to cover. Your exam preparation should therefore involve making summary notes from the wealth … Continue reading EM Waves: Uses and Dangers
Energy Transfers in Electric Circuits
The amount of energy transferred in an electric circuit can be calculated by multiplying the current, time and potential difference. This is expressed in the equation given below. Current is measured in amps (amperes), time is in seconds, and potential difference in volts. Remember that the symbol for current is the letter I - not … Continue reading Energy Transfers in Electric Circuits
Molar Heat Capacity
There is a required practical in GCSE Physics courses, including Trilogy, that involves calculating the specific heat capacity of different metal blocks. This is done by measuring the energy supplied (using voltage, current and time) and monitoring the temperature increase. You are expected to recall this experiment and be able to suggest how it could … Continue reading Molar Heat Capacity
Magnificent moles
You may well ask, what is the point of an SI unit that measures “amount”? Surely if we want to know an amount then we simply count whatever it is that we need to quantify. That’s fine until we get to VERY large numbers. How large? We’re talking here about numbers that are massively bigger … Continue reading Magnificent moles
Farewell to Hunterston B
As was announced back in August 2020, the second reactor at Hunterston B nuclear power station is being "switched off" today (7th January 2022). Interestingly, one UK newspaper reported this as an "early" closure as the plant's owner, EDF, had originally hoped to keep it running until 2023, but this has to be put into … Continue reading Farewell to Hunterston B
Heisenberg and Sheldon; speed and uncertainty
In my very last Y11 lesson of last term I did a 15-minute dash through some of the weirder bits of physics, including Heisenberg's uncertainty principle. This says that, for example, you cannot know the exact values of an object's position and speed (actually its momentum). More excitingly, you cannot know the exact energy of … Continue reading Heisenberg and Sheldon; speed and uncertainty
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
Non-binary electrons
On the final day of term, a member of my form tested me with a series of science jokes, the first of which was; “Why does a beef burger have less energy than a steak?” Pause here if you want to come up with your own solution. I must admit that I didn’t guess the … Continue reading Non-binary electrons
