Month: October 2008

Unusual resource for explaining Joule’s Law

An offshoot of Joules’ Law is that when transmitting electrical power, the current is kept as low as  possible in order to reduce energy losses associated with heat of the electrical cables. Because the power being transferred is the product of the voltage and the current, we can still get the same power transferred if we halve the current and double the voltage, or; make the current very, very small and make the voltage very, very big.

So power -lines transmit power at a voltage of up to 400,000 volts. Then, as the power gets closer to the home, the voltage is reduced in stages, and correspondingly the current gets increased. This occurs in appiances called transformers.

I came across a lovely interactive explanation of this when in honeymoon in Hong Kong.
I couldn’t resist.

Another Physics teacher shares resources on Youtube

Tom Healy teaches Physics in Cabinteely Community School and for quite a while now has been uploading revision videos on Leaving Cert Physics to youtube. He has almost 50 up there by now and has divided them into Mandatory and Non-mandatory experiments.

A wonderful way to revise, but also a wonderful resource for any new teachers.
Why couldn’t this have been available when I was starting out?

Mr Devitt teaches us about Light

Jerome Devitt (History Teacher) runs a transition-year module on Light and Sound for theatres, and kindly agreed to allow us in to watch him teach one of his lessons.

Not all of it comes out great on video, but it should still prove very usefull for Senior Phyics classes.

If you would like to play with a virtual version of this, where you can control the postion and intensity of the lights, click here.

Thanks Jerome

Support for physics teachers: The Institute of Physics

The single greatest resource I have access to in my profession is the Institute of Physics’ (IOP) discussion forum. Any query I have ever had has been satisfactorily answered. It works because it has a large critical mass, although like most forums most members are happy to just read, which is fine too. I imagine this is partly due to lack of confidence, which would also explain why similar forums here are not as successful.

Nevertheless, if you reading this as a physics teacher you could do a lot worse than join the PTNC Phyics discussion forum.

While you’re at it why not join their Schools & Colleges Affiliation Scheme? You get a monthly magazine/journal (called Physics World) which keeps you up to date with latest developments in physics, and it’s pitched at just the right level for teachers. There’s also their Physics Education monthly journal, and they offer lots of resources like posters and DVDs, which make a very pleasant surprise when they arrive in the staffroom letterbasket.

Check out their schools and colleges page for an overview of what’s on offer, and make sure you watch the animations on the radioactivity page.

Money well spent I’d say myself.

The old bed of nails

We have Open Day coming up and I was considering using the bed of nails. It’s certainly impressive, but I think we may not have enough room or time on the day.

It’s pretty cool though. And the nice thing about it is that the more nails you have on it per unit area, the more dangerous it looks but the safer it actually is (from Pressure = Force / Area).

Then all you need to add is another bed on top, and on top of this a cavity block.

Then smash the block with a sledge-hammer (this to demonstrate the property of inertia).

Then add more beds!

More teaching ideas from teachers tv

My friend Dee Maguire reminded me recently of some very useful videos on teachers tv of physics teacher David Robinson in action. Some of these are also on youtube:

The magnetic gun is also referred to as a ‘Gaussian gun’.
We had a bit of fun puting a basic one together at the end of class the other day.

             

       

Other video clips of David demonstrating can be found here on teachers tv; the radioactivity clip is particularly impressive.

You can also enter his name into the youtube seachbox for other demonstrations.

Thanks Dee