Physics

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

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.

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).

The Physics of Christmas

Related Links, courtesy of the PTNC forum

Is Santa Real?
A scientific debate which looks at both sides

Star of Bethlemen
What are the possible explanations? (in swf format)

Noradsanta
Ian Robertson has provided the following nugget:
At xmas every year for some 24 hours by far the busiest website in the world far is Norad Santa . Here the men and women of the North American Aerospace Defense Command behind the strongest doors in the world protecting their command centre under Cheyenne mountain use a range of surveillance technology to track Santa’s sleigh.
Kicks off in December.
Santa 2025
An uptodate activity (you need to register):
Santa is planning ahead for when humans colonise the rest of the Solar System – he may decide to move to another planet! In this fun activity pupils analyse planetary data to find which planet best satisfies Santa’s future requirements.

They then e-mail Santa to advise him of their decision, and – if you wish – design a Christmas card to show why this planet is such a great place to spend Christmas.

Teachers’ Domain

teacher’s domain http://www.teachersdomain.org/sci/index.html is a wonderful resource for teaching (and learning). You should register, but if you’re just checking it out you can ‘take a test-drive’. Alternatively you can simply click on the test-drive option if you want to call up a video-clip without having to sign in.

Not all of the resources are videos, and as always check them out yourself in advance before showing them to the troops.

I have linked to many of the useful physics ones on my site, but if I had to pick one clip it would probably be this one. At 1:15 it’s just what you need to reinforce a very strange idea indeed!

http://www.teachersdomain.org/resources/phy03/sci/phys/matter/atoms/index.html

Ted.com

Mny of the best resources on the internet involve video-clips which unfortunately are not available in most schools.

One resource which is available is www.ted.com

As it says itself “Inspired talks by the worlds’ greatest thinkers and doers”. wonderful

Science and Astronomy talks are there, along with much, much more.

Many of these involve concepts which should be part and parcel of out students’ education, but because of the inertia involved in education will probably never appear on a syllabus until they in turn have become obsolete. If nothing else it’s nice to listen to a talk in the background while doing other work on the computer.

It “brings together the world’s most fascinating thinkers and doers, who are challenged to give the talk of their lives (in 18 minutes)”.  It tends to be the antithesis of our conventional educational system in that it encourages interdisciplinary links rather than pigeon-holing knowledge into autonomous subject areas.

This talk by James Watson of The Double Helix fame is a perfect example. We / I need to show these more often in class.
http://www.ted.com/talks/view/id/35

Currently listening to ten ways the world could end:
http://www.ted.com/index.php/talks/view/id/167

quiz with a difference

Saw this recently in a physics education journal (IOP Classroom Physics).
I’m probably the last person to have come across this, but still . . .

When giving a quiz why not give the answers and have the troops figure out the questions?
It gets them thinking, as opposed to simply vomiting back up the facts they learned off the night before.
Here are some sample questions / answers for junior cert magnetism:

1. Iron, cobalt and nickel
Which elements are magnetic?

2. They repel each other
What do two north poles or two south poles do when they are near each other? 3. It lines up with the magnetic field
What does a magnetic compass do?

4. A region of space where a magnetic material experiences a force
What is a magnetic field?

5. Increasing the number of coils on an iron core
How could you increase the strength of an electromagnet?

6. Away from the north pole and towards the south pole
Which way does a compass needle point when near a magnet?

7. You end up with two smaller magnets
What happens when you break a magnet in half?

Progress is slow

Have been playing with electrostatics quite a bit lately, partly to try and establish how to guarantee that the demos will work as expected (see previous blog).
When it works well it is actually very impressive, but taking a video of this gives the impression that it is always this straightforward, which is not at all helpful to new teachers who will expect everything to work perfectly first time, and may be silly enough to not have gone through it themselves beforehand.

On the I.T. front, I stuck a few aul’ videos onto youtube and googlevideo. They certainly allow for better quality viewing than downloading straight from thephysicsteacher site, and also allow for feedback which will hopefully prove useful.
The disadvantage is that they are almost definitely blocked in most schools, so can only be viewed at home.
Youtube has a time limit of 10 minutes, which is a pity because apart from short demonstrations, many of the video clips I have are twice as long. Googlevideo is not as popular and I have also had quite a few problems uploading. This sure is one big pain in the rear end.