One of the most important laws of Physics is perhaps one we have all heard once in a while – the second law of thermodynamics.
This law states that the entropy – in a closed system – in which we can infer as the Universe, will always increase.
A common misconception with the term entropy is that it is a measure of disorder. A “disordered” state does not necessarily mean that it has high entropy and vice versa. Entropy is rather the number of ways particles can be arranged. We can take tea and milk as an example, as many people do. Looking at the tea and milk system, at the instantaneous moment when you pour milk into tea, it is perceived to have low entropy, this is because the milk molecules are virtually sitting on top of the tea molecules. When you wait for a second or two until the milk starts to blend and dissolve into the tea, the system begins to increase in entropy, because there are so many more ways for the milk and tea molecules to arrange themselves in this sense, rather than being stacked on top of each other. Continue reading →
Most of the energy we use to power technology come from finite sources which are not sustainable. This energy which may be in the form of either fossil fuels, coal or even nuclear fuels and so on will eventually be used up. However renewable sources such as solar power will not run out…..until the sun runs out of hydrogen fuel but that’s another story.
We are able to harness the light energy radiated by the sun by the used of solar cells. A solar cell is an electronic device made of semiconductors which exhibit the photovoltaic effect to convert light energy into electrical energy. Semiconductors are materials which lie between conductors and insulators. A conductor is a material which is composed of atoms in which electrons are easily freed from the nuclei. Even though it is able to form a current, it remains electronically neutral as there are the same number of positive protons and negative free electrons. An insulator, on the other hand, is a material which is composed of atoms which hold more tightly onto their electrons so they have no free electrons like conductors. Current is a measure of the rate of flow of charge through a material, with the electrons being the charge carriers transporting energy across a circuit. Continue reading →