Physics

My tip for the Leaving Cert Physics paper

The Large Hadron Collider (LHC)  in CERN will be the world’s largest particle accelerator when its construction is completed sometime this Summer. It’s a pretty big deal if you are a particle physicist, and even if not you are still likely to be bombarded with the news when it is finally switched on.

‘Tips’ aren’t really a good idea for the Leaving Cert Physics paper, but if I had to guess I would suggest that something in this area is going to make an appearance on the Particle Physics question this year.

To find out why this is such a big deal you could do worse than watch Brian Cox talking at TED this year.
The Higgs particle isn’t on the syllabus but it should be. It’s probably the Holy Grail of Particle Physics. It aims to explain why particles have mass, which isn’t as silly as it sounds (apparently).

‘Course I could be completely wrong.

 

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Fun with the Van der Graff and Animoto

A study of concentration

We had the usual fun with the Van der Graff today. The weather was rather accommodating, and it tallied nicely with the last class before the long weekend.

I have never got a student’s hair to stand up dramatically, but i was drying the canvas belt with a hairdryer when I realised I could help things along a little by aiming it upwards into Fania’s hair. It loosened up the hair very nicely and the show was much more impressive as a result. I also got a student to hold up a mirror so Fania could see for herself what everyone else was laughing at.

I have seen a few examples of Animoto and how it does a pretty cool job of presenting photos, so I thought I’d head on over and check it out.

It really is pretty impressive, and very user-friendly. There might be a couple of thinks I would change, but then again that may just be me not familiar with the program.

It allows for automatic uploading to youtube, which was a pleasant surprise. The free version limits the clip to 30 seconds, so I might just invest in the longer version to check it out.

This is a clip I uploaded last year

 

When is a kilogram not a kilogram?

Many physics students will be familiar with the fact that the prototype kilogram is kept in a high-security vault in Paris. What I didn’t realise was that the mass of this specimen is changing, albeit very slightly.

So here’s the question; if this is the one and only true version of the kilogram, and it loses mass, doesn’t it still stay a kilogram?

And doesn’t that mean that other copies, which would have been correct originally, are now wrong?
(I think in fact that they may all be losing mass slightly.)

Something very unscientific about all this . . ., no wonder physicists are embarassed about it.

Seems a bit like when kids make up the rules of a game, and when it turns out that these don’t suit the leader of the gang, he just changes them.

Which seems as good an excuse as I am likely to get to show Eddie Izzard – Do you have a flag?
 

 

More youtube and some Flickr

Decided it was time to see what I could do with Flickr, so I spent the day taking photos of Junior Cert Science demo apparatus. The plan is that I will show this to students and they will have to name the demonstration. Hopefully it will help the second-years revise for Summer exams. It must be rather daunting to have to go from a year of short class tests, to a set of formal exams which require knowledge  taken in over the whole year.

Students can hopefully access this themselves if they wish, although I may  print it off for those who don’t have the facilities.

Bloody nice spectrum though innit?

Thanks Conor!

Of course there’s still the bread ‘n butter leaving cert material:

 

The Photoelectric Effect

I have been trying to get this to work for years, without success. And then recently I tried it again and lo and behold it worked like a dream!
Part of the problem was that if the day was even slightly humid the gold leaf electroscope wouldn’t hold its charge.
Secondly it had to be charged negatively, and I was never sure if I was charging it positively or negatively.
Thirdly I didn’t realise that I had to sandpaper the zinc in advance to remove the oxide layer.
Fourtly I don’t keep a list of questions related to demonstrations which I can’t get to work, so I only remember that there is a problem when I go to teach it each year, instead of asking an expert.

And I apologise for stating that this is “the most important least impressive experiment in the history of science”. It is actually rather impressive.
If I do say so myself.

Microscale Vacuum Apparatus

microscale-science

This went down well at the ISTA conference in Letterkenny at the weekend where I was demonstrating as part of the Science on Stage team and I promised people I would let them know where I got it, so here it is:
teachersource.com

There is a lot more where this came from. I posted a brief note on the site recently , so browse the entire site. Remember the dollar has rarely been this low.

I will stick a video of the kit in action on youtube sometime this weekend (hopefully).

Chernobyl: the legacy

348910187_58dea72f81_m.jpg

Photo from Jeremy Nicholl on flickr

I have mentioned this before, but it’s worth throwing it up again (and again)

Given the low radiation doses received by most people exposed to the Chernobyl accident, no effects on fertility, numbers of stillbirths, adverse pregnancy outcomes or delivery complications have been demonstrated nor are there expected to be any. A modest but steady increase in reported congenital malformations in both contaminated and uncontaminated areas of Belarus appears related to improved reporting and not to radiation exposure

Source: World Health Organisation

It is a similar story for the survivors of the Hirishimo and Nagaski nuclear explosions.

This is always greeted with (i) disbelief, (ii) scepticism or (iii) amazement (at best) by my senior students.

I guess it’s very to argue with our gut feeling. But this is ultimately why we have this thing called SCIENCE, even if it is warts and all.