Month: December 2007

Apology to Students: Matlab from Hell

To every student who ever gave up Physics – especially those who left my own class over the years; I feel your pain. My very last class in 2007 was involved an experience just like this with Alex and his calculator trying to use the formula for geostationary satellites.

I’m not so old that I don’t remember what this feels like, in my case it was accounting.

Had a happy 2007.
The highlight was getting to see three of biggest living heroes; Steve Earle (Midlands Music Festival), Guy Clark (Johnny Keenan Banjo Festival) and John Prine (NCH), all within six months of each other.

I am only allowed to say that now because in two days I am getting married.

Have a happy 2008
 

Guy Clark:

John Prine

Steve Earle:

Junior Cert Science Investigations

Our third years have started their junior cert investigations. The physics version is to compare the insulating ability of different materials.

Seems very basic, in fact too simple to qualify as an investigation at this level.

Until you try it out.

I don’t have third years this year but I walked in to PO’s class to see how he was getting on . They were starting off with a control: Putting 100 ml of water into an uninsulated calorimeter and plotting a cooling curve.
But they ran into problems straight away. It took ages for the water to cool down from a starting temp of 80 degrees.  So they are wondering how they will manage when it is insulated.

One student came up with the clever idea of using a set time and noting the temperature drop for different materials.

Others suggested using a smaller volume of water to begin with. So then we had to decide which was the best idea, and more importantly how would we decide which was the best idea.

Test them by experiment – bingo. 

Now we were getting into it. Conflicting ideas, not quite getting published in a peer-reviewed journal, but nevertheless good stuff. Next we will look at whether we can carry out valid comparisons, but just arguing over it introduces a personal ownership factor as opposed to just following the traditional cook-book receipe.

Then there is still the issue of making sure ‘amounts’ are equal; equal by volume or equal by mass?
And oh my goodness, what if there is no one right answer?

Their homework was to come up with their own ‘hypothesis’; not which was the best insulating material, but rather which is the best way to test this.
Then the bell went and they reminded us that we wouldn’t see them again until  January.
Oh well.

I discussed this with PO last year.
The key is for us teachers to get comfortable with this approach and try to adapt all experiments so that they can be carried out in this manner. There may just be hope for us yet.

The Stanford Prison Experiment

There are some things which are worth knowing which are outside the realm of Physics.

I have often thought it questionable to brand a specific generation of Germans as morally (and by implication genetically) inferior because of their role in the holocaust. It’s not to excuse what happened, but rather to acknowledge that if you or I were living in those circumstances in that period, chances are we wouldn’t have acted any differently, and we need address what that says about us.

The Stanford Prison Experiment carried out in 1971 illustrates this better than anything else I can think of.  I have been showing it to my senior classes over the last day or two of term. Hopefully it will encourage some of them to ask questions.

Initial feedback was very positive.
One more reason why it’s crazy not to have youtube in schools.

The clips get taken down and others post them back up from time to time, so do a search for “Stanford Prison Experiment” on youtube.

This is a variation on the above; it’s a talk from Dr Philip Zombardo, who co-ordinated the experiment in 1971.

The Lucifer Effect: Understanding How Good People Turn Evil. In this book, Philip Zimbardo summarizes more than 30 years of research on factors that can create a “perfect storm” which leads good people to engage in evil actions. This transformation of human character is what I call the “Lucifer Effect,” named after God’s favorite angel, Lucifer, who fell from grace and ultimately became Satan.
From Youtube

Ten Great Ideas

Been thinking about my previous posting.

What are the ten great ideas in Science that we don’t emphasise?

The average student remembers bugger-all about science, but if we were told there were ten things that a student had to remember, what would they be?

1. Kinetic Theory – Everything is made up of atoms and vibrate at temperatures above -273 degrees Celsius.

2. Evolution

 3. Global Warming

4. Each atom is 99.9999% empty, and so therefore all objects which appear solid are almost completely empty space.

5. Deep Time: The age of the universe, the age of the Earth, the age of first life, and the age of humans

6. Science does not offer Absolute Proof

7. Fundamental Attribution Theory: Humans are genetically hard-wired to apportion blame for our own mistakes to others while wishing to take the credit for achievements which are outside our control.

8. Quantum Theory

9. What Science doesn’t know

10. Mass Extinctions

Where does the ‘stuff’ in trees come from?

learner.org is an interesting site which “uses media and telecommunications to advance excellent teaching in American schools.”

One of the issues they address is the area of misconceptions in Science.
This is a wonderful video which asks where does the material that makes up trees come from.

College graduates from Harvard and MIT were asked and not one of them gave the correct answer. In fact their answers were very similar to those given by six year olds.

It makes us question what other serious misconceptions we are responsible for, and leads us to question what and why we are teaching.

If we put together the ten most important ideas in science, how many of them are emphasised in our science courses?

College students answering these questions kicks in at about the 8-minute mark.

A primary school kid gets a look at solid air (dry ice) at 53:20. The look on his face is worth waiting for.

The video is 1:21 long. Access it here

Some nice Modern Physics resources

I think my first post here was on teachers.tv. They have just released some new gems on particles, presented by Brian Cox.
They include The Forces of Nature, The Building Blocks of Matter and The Hunt for the Higgs.

Some of these include interviews with Murray Gell-Mann. Follow this up with an entertaining presentation from the Nobel Laureate himself at Ted.com

In Search of Giants

Gell-Mann on TED.com

Pressure and Boiling Point

I’m in the middle of writing of up reports (who isn’t?) and don’t have a lot of free time, but a couple of times this week I have tried to get the Pressure and Boiling Point demonstration up and running. I figure that as a so-called experienced teacher I should be able to work this without too much trouble. After all it is in all Junior Cert text-books and presumably is on the syllabus – the implication is that every teacher does this.

 I set it up with a partial vacuum caused by running water (how many people use this as a wonderful way of teaching about particle motion?).
Nothing

I set it up with an electric vacuum pump.
Nada.

I have put hours into this.

If water could laugh mine would be wearing a smile from cheek to cheek. I imagine I am not forming a sufficient seal, but don’t know how to improve it.

So I resort to youtube. Don’t tell me using the internet to show demonstrations is the lazy option. I try, I really do. I just don’t have green fingers when it comes to this sort of thing.
The worst part of all this is that I now have to go back to Mr O’ Boyle and ask him to show me again how he does it.
And he’s a Chemistry teacher – oh the shame!

Now while checking that this link still works I came across this beauty – off to try it again tomorrow.

We are muppets

Wouldn’t it be nice if once a year every teacher had to take a little time to think about what they had achieved in the previous twelve months. Did it tally with what we wanted to achieve? Did we have any objective in mind?

We become so swamped by the day-to-day issues we rarely (if ever) take a step back to reflect on why we first entered teaching. What happened those great aspirations we had when we first walked into a classroom?

I’ve been thinking about this because this is my tenth year as a full-time teacher, and I need to take stock of what I’m doing.

For me teaching is not about handing out facts and figures to be ‘learned off’. It is (or should be) about enabling the students to become independant learners; to encourage them to think for themselves, not only in science but in their day-to-day lives; to question everything.
For me one of the greatest isssues is: To what extent is our high standard of living based on the exploitation of the Third World? I feel very strongly that it is a case of ‘out of sight, out of mind’, and that’s just not good enough.

So what have I done  about it?

Nothing
“All it takes for evil to flourish is for good men to do nothing.”
 – Edmund Burke

Magnets are so cool

Magnets are possibly the coolest thing on this planet. Einstein was fascinated by them, as is every kid who comes across them. Not only in Junior Cert but also in Leaving Cert. We just don’t do enough with them.

I have to admit to being just a tad obsessed with them myself.
There is a Junior Cert activity where you hang a bar magnet so that it aligns itself North-South. I never bothered with this because hanging the magnet from a retort stand meant that the magnet became attracted to the metal in the stand. Hanging it anywhere in the lab would have resulted in it being attracted to nearby metal (or so I thought) and getting a saddle for the  magnet to sit in was also a pain.
Then there is the issue of the magnets losing strength and becoming less effective.

 Discussing it with my Chemistry colleague Peter O Boyle, he showed me a simple way to hang the magnet, so I tried it with a recently purchased bar magnet, and just let it hang form my hand. And to my great amazement it worked a treat!

I know plotting compasses do this anyway, but there is something very weird about holding a piece of metal on a string, and no matter what way you turn around, the metal continues to stay still (or nearly so). Something very weird indeed. And it’s a feeling you don’t experience with a textbook

Apologies to everyone I have ever taught for not trying this before

‘Course nowadays there is a new generation of magnets of  which Neodymium seem to be the easiest to get hold of. There must be a bucket load of cool things to do with these.

 They certainly make the demonstrations in ElectroMagnetic Induction work a lot more smoothly.

One impressive application is ‘The World’s Simplest Motor’. Nobody should be allowed teach magnets again without getting the students to make these (there are even easier alternatives – do a search for ‘homopolar motors’ on youtube).