Bragg on Bragg

Lord Bragg of Wigton, a former pupil of the school, has a great interest in Physics and has done a lot to promote Physics through his Radio 4 programmes. I've posted about his book "On Giants' Shoulders" before. You can borrow it from Wigton library.

This week, Melvyn Bragg's In Our Times programme has been about Crystallography. This is basically when you fire X-rays at the atoms in a crystal. The gaps between the atoms act like slits so the the X-rays spread and interfere with each other as they pass. The complicated pattern that you get can be interpreted to give the structure.

Here's the link to the programme. I think it's valid for a year.

http://www.bbc.co.uk/programmes/b01p0s9s

Two of the key founders of this area of study were William Henry Bragg and his son Lawrence Bragg. William was born at Westward, very close to Wigton. They both won the Nobel Prize for Physics, the only parent/child duo to have done so.

Time

Castlerigg Stone Circle near Keswick must be one of the earliest scientific sites, if you think about it. Scientists make careful observations and record them. These ancient people made careful observations about the movement of the Sun through the seasons and recorded it. It will be impressive if modern scientific findings are as durable. The study of time is one of the most important areas in Physics. What exactly is time? One of my teachers said that it was the thing that meant that two objects could occupy the same space. (Think about it!) Isaac Newton thought that time was independent of space - as if there was a big clock sat outside the Universe so that there is the same time everywhere. Einstein showed that isn't true. First, light has a fixed speed, so that when I look at the Sun, it is like it was 8 minutes ago because that's how long it takes the light to get here. What does that do to the concept of NOW? Secondly, Einstein showed that time can be stretched if you travel fast. A second takes longer if you are travelling faster. To understand this, read Einstein for Beginners. It's in the school library. See my other blog for details: http://www.idareyoutoborrow.blogspot.co.uk/2012/10/einstein-for-beginners.html

Brilliant science podcasts

One of my fellow science teachers found this brilliant set of explanations of scientific ideas:

http://www.nakedscientists.com/

"Naked" as in stripped down to the bare essential ideas, rather than, well, you know what.  Try telling that to the school's locked down Google!

Magnetic nail polish

Perhaps this could be sub-titled "An old man makes a fool of himself"??  My Physics teachers's email network alerted me to magnetic nail polish. You apply it and whilst it is wet you hold the cap of the bottle over your finger nail. The cap contains a patterned magnet which pulls iron filings (one person suggested cobalt, which is also magnetic) into the pattern of the magnets.  I had a great time swanning around with it on at school...

Two things Lower Sixth students should consider

You should consider becoming a 16-19 member of the Institute of Physics.  It's free.

Follow this link:
http://www.iop.org/education/student/youth_membership/page_41684.html


I've explained about the Headstart programme of university taster courses that one of last year's students went on.  They are mainly Engineering and the Physical Sciences, but might help you to decide about a more vocationally based course for a subject that you haven't studied in school.

These courses cost, as far as I can see.

http://www.etrust.org.uk/headstart.cfm

Those Horizon programmes

BBC2 has shown two brilliant Horizon documentaries on the Physics of the entire Universe and the Physics of the really small.

http://www.bbc.co.uk/iplayer/episode/b01mgllj/Horizon_20122013_How_Big_is_the_Universe/

http://www.bbc.co.uk/iplayer/episode/b01mmrc0/Horizon_20122013_How_Small_is_the_Universe/

Hopefully these will still be valid for the next week or two.  Watch them!

A colourful oil stain

Here's an oil stain in the road at Castleton in Derbyshire.  What happens is that oil forms a thin film, like the skin on a bubble.  Remember that not only can light pass through glass, it can also reflect as well - "a man who looks on glass, on it may stay his eye, or if he pleaseth through it pass and then the heavens espy"!  When light hits the top surface of the oil, both things happen.  Some light reflects towards your eye and some goes in to the oil.  The light that goes into the oil hits the far side of the oil and reflects back towards your eye.  So there are now two rays of the same light heading for your eye.  Where the waves line up correctly peak-with-peak you see a colour.  This is called constructive interference.  The colours all have different wavelengths so they line up in different places giving you the rainbow effect in the oil.

The cattle grid in Glen Nevis

Last week we sat on the slopes of Ben Nevis looking down on this cattle grid.  Our seat was near the top corner of the isolated patch of woodland in the picture.  We noticed that there was a big time delay between seeing the car hit the cattle grid and hearing the sound.  I timed it.  Now is that sad?  Anyway, the values were 2.74 and 2.61 seconds respectively.  If we assume the speed of sound in air to be about 335 metres per second, then that means we were sat about 90o metres away. To read about the way in which air temperature affects the speed of sound, try this Wikipedia link: http://en.wikipedia.org/wiki/Speed_of_sound

If you go to The Sky At Night TV programme website http://www.bbc.co.uk/programmes/b006mk7h and scroll down, you'll find the April Moore Marathon Observing guide. It lists 55 things to look for to celebrate 55 years of the programme. My telescope is not for stars but I took this photo of the Moon. 3/4 of the way up on the left hand side, there a small dark crater in a lighter band. This is the crater Plato, one of the 55 objects. The section around it is called the Alpine Valley, another of the objects.

The Sky At Night

The Sky At Night is the longest running BBC TV programme, I think. I've never managed to stay up late to watch it, but the website is good, and of course it's on the i-player now. There are even repeats on BBC 4.
http://www.bbc.co.uk/programmes/b006mk7h

I am interested to note that Mercury will be visible around sunrise from the middle of next week, looking south east. That means maybe 8 in the morning, so I shall be looking from my lab window when I get to school.

Jupiter was very bright in the sky over Wigton tonight, looking south west at about 6pm.