Focusing is the term that describes parallel rays of light being brought together into a single point, known as the focal point. Electromagnetic waves can be focused using either refraction (with lenses) or reflection (with mirrors). Both of these effects can be explored in the excellent geometric optics simulation that has just been unveiled by … Continue reading Focusing EM Waves
Properties of EM Waves
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
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
Online Circuit Simulators
One of the best ways to learn about circuits and resistance is by building circuits - either in the classroom or using an online simulation. I've previously recommended PhET DC Circuit simulation, which (despite some non-standard circuit symbols) is still a great way to take measurements that demonstrate concepts such as Ohm's Law. You can … Continue reading Online Circuit Simulators
Series and Parallel Circuits
Electric circuits are all about energy transfers: they allow the energy in the original source to be transferred via electricity into some other form. In the classic torch-bulb circuit, for example, chemical energy (in the cells) is converted into electrical energy, which is then converted into light (and heat, for old-fashioned bulbs). The amount of … Continue reading Series and Parallel Circuits
Circuit Simulation
The excellent circuit simulation that we explored in our lessons is freely available for you to use as part of your independent learning. It was created by the University of Colorado and can be accessed here (or just search for PhET DC simulation). There are, however, a couple of points that you must remember when … Continue reading Circuit Simulation
Mr Tarrant's physbang 'blog 