Given my fondness for the band of the same name, it is strange that I have not used this title for a post before. AC/DC refers in this case to alternating and direct current. Mains electricity in the UK is 240 volt alternating current that switches polarity (flows the opposite way) 50 times a second …
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Resistance Is Useless…
Sometimes exam questions about circuits will use resistors instead of lamps. Lamps are just like resistors except that they glow white-hot whereas resistors do their resisting more discreetly. Solving problems with resistors instead of lamps uses all the same principles. Often they include ammeters to show the current flowing in a particular part of the circuit and ask …
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Ohm’s Law…
Understanding electric circuits is all about understanding the relationship between voltage, resistance and current. The voltage is the amount of electrical push in the circuit. This is usually controlled by the number of cells. Each cell is 1.5 volt so four cells connected in series are called a 6 volt battery. The picture to the left offers …
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But That Is Illogical Captain…
Mr Spock is the highly logical Science Officer supporting the impulsive Captain Kirk at the helm of the star ship Enterprise in the long running TV and film franchise – Star Trek. I seem to remember him often saying, “But that is illogical, Captain” although I cannot find a single example. Logic plays an important …
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Static Charges…
I want to be an astronaut when I grow up. He refers to the water as a bubble. It is not a bubble but a sphere of water. Other than that it is pretty awesome. Especially making a looping! Questions…
Magnetic Field Lines…
A bar magnet has two poles; the north-seeking pole (labelled N) and the south-seeking pole (labelled S). The magnetic force is concentrated at the poles. This can be shown by placing the magnet beneath a thin sheet of card and scattering iron filings over the top. The darker patches of iron filings correspond to stronger magnetic forces. The …
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Einstein’s Theory of Relativity (Part One)…
Well done for sticking with the blog this week. I hope that it will have given you some opportunities to think about science in a different way than in lessons. This is the last post of the week and is something that is obviously unlikely to come up in an exam but is fun to …
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Diode…
Diodes are electronic components that only allow the current to pass in one direction. They are used for smoothing out alternating current and filtering out the audio from radio transmissions. Laser diodes and LEDs emit light.
Waves…
I think you just need to have fun with this. I have tried to set up a standing wave and have failed. This would pulse up and down constantly without collapsing. I can get a standing wave but then it collapses before starting again. Explore ideas about wavelength and amplitude. If you have any questions, …
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Eratosthenes…
I was marking a Winchester paper a while back that had a question about Eratosthenes. Winchester don’t often make mistakes in their papers but on this occasion they spelled it Eratothsenes throughout. I realised that this meant it could be spelled using the elements – ErAtOThSeNeS (erbium, astatine, oxygen, thallium, selenium, neon and sulphur). Sadly the correct …
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