Keele Observatory Trip May 20, 2012
Posted by Mr G in Astronomy, Physics.add a comment
Finally, a spare moment to get the photos from my camera…
Enjoy the slide show.
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Mr G
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Physics Revision Videos – AS Unit 1 March 14, 2012
Posted by Mr G in Physics, Revision, Y12 & 13.Tags: AS, Physics, Revision
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Below are the topics of AS Physics – Unit 1.
Where possible links to videos (e.g. Khan Academy) have been added – more will be added over time – Units 2, 4 and 5 to follow
Mr G
AS Unit 1
HFS
- Equations of motion – Calculating Ave Speed, Solving for Time, Displacement from time and velocity, Acceleration, Ave velocity for constant acceleration, Displacement from time, acceleration and initial velocity -
- Motion in 2D – Part 1, 2, 3, 4, 5, Total Displacement, Projectiles at an angle – K
- Motion graphs – Why is distance from the area,
- Vectors and scalars, Vectors in 2D - K
- Free body force diagrams
- Resolving vectors into components - Components of forces – inclined plane -K
- Combining vectors by drawing
- Combining vectors at right angles
- Newton’s first and second laws – K
- Gravitational field strength
- Newton’s third law – K
- Kinetic energy
- Gravitational potential energy
- Work done – Intro, Part 2 - K
- Power
EAT
- Density
- Laminar and streamlined flow
- Turbulent flow
- Viscous drag
- Upthrust
- Terminal velocity
- Stoke’s Law
- Viscosity and temperature
- Elastic and Plastic deformation
- Brittle
- Ductile
- Hard
- Malleable
- Stiff
- Tough
- Force-extension graphs
- Limit of proportionality
- Elastic limit
- Yield point
- Hooke’s Law
- Stiffness
- Tensile & compressive stress
- Tensile & compressive strain
- Breaking stress
- Young’s modulus
- Elastic strain energy
Link Key
K – Khan Academy – Physics
A Month of Spectacular Space Weather January 25, 2012
Posted by Mr G in Astronomy, Physics, Space Travel, TV.Tags: aurora borealis, aurora photos
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The Sun has been pretty busy lately, with lots of flares and coronal mass ejections sending high energy particles flying towards the Earth. These can cause problems, both in space and on the ground.
Fortunately the Earth’s magnetosphere deflects most of these away from us. But the field comes back to Earth at the poles and these high energy charged particles come rushing down into the atmosphere (in some cases accelerated by the Earth’s magnetic field).
These particles “excite” the atoms in the air by giving the atoms electrons more energy, which then get rid of the energy again as light. Blue or Red for nitrogen (70% of the air) and Red and Green for the oxygen.
At high altitude oxygen red dominates, then oxygen green and nitrogen blue/red, then finally nitrogen blue/red when collisions prevent oxygen from emitting anything. Green is the most common of all auroras. Behind it is pink, a mixture of light green and red, followed by pure red, yellow (a mixture of red and green), and lastly pure blue.
Just like iron filings line up along a magnetic field, so do the charged particles. We get sheets of air glowing when hit by the particles following the Earth’s field lines, drifting and swirling around. We call them Aurora. Aurora Borealis (a.k.a. The Northern Lights) and Aurora Australis (The Southern Lights).
Here is a BBC Stargazing Live video explaining Aurora – it’s aimed at Primary kids so it’s kept nice and simple.
Below is a slide show of Aurora photos taken during January 2012.
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Mr G
Sources: Wikipedia, BBC News, BBC Stargazing Live, Various Newspaper websites.
Is anyone out there…? Chance they are just got bigger! January 13, 2012
Posted by Mr G in Astronomy, Physics.comments closed
The existence of life outside our planet just got a bit more likely.
Following years of finding planets around other stars, a new study thinks that every star has planets which form from the remaining material in the gas/dust cloud that formed the star. The study – originally published in Nature magazine is also discussed in this BBC News article.
That means there are likely 10 Billion (10,000,000,000) planets that are like Earth in size. Many of those could be the right temperature and have the right chemistry for life to have developed.
One thing to bear in mind – we currently don’t know how to travel faster than light so even if aliens do exist – unless they do know how we might never meet them.
Mr G
Sources: Nature, BBC News
Curiosity and the God of War November 29, 2011
Posted by Mr G in Applied Science, Astronomy, Physics, Space Travel.comments closed
The Curiosity Rover has started its journey to Mars. The Mars Science Laboratory (aka Curiosity) is biggest robotic probe we have ever sent to Mars, the size of a car. It is 5 times larger and 10 times the mass of the two rovers Spirit and Opportunity that we landed on Mars in 2004. Each was due to run for 90 Mars days – Spirit finally broke in 2010 and Opportunity is still going having driven 21 miles so far. The Curiosity rover is nuclear powered – so it does not rely on solar panels – should be running for 668 Mars days (which are slightly shorter so this is 688 Earth days). It might run a lot longer though if it does as well as the previous two.
Here is the launch…
Landing something that size is a problem – before we wrapped probes in air bags and after a parachute slowed it down they bounced onto the ground.
This one needs a bit more care. It involves a heat shield, a parachute and a rocket powered hovering crane that lowers the rover the last few meters.
This is a computer animation of what the rest of the journey will be like.
It’ll hopefully land at Gale Crater on Mars in August 2012.
Mr G
Sources NASAKennedy YouTube channel, The Guardian, Wikipedia
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First Post of the Year – First New Science from the LHC November 16, 2011
Posted by Mr G in Applied Science, How Science Works, Physics, Y12 & 13.comments closed
The Large Hadron Collider has been running for over a year now and scientists have a massive amount of data to go through.
So far they have been looking for things we already know about, just to check the thing is working properly.
Now they have started looking for new Physics – in this case trying to work out why the antimatter and matter created at the Big Bang did not cancel each other out. 1 particle in billions of billions got left behind.
LHCb, the detector looking for the beauty quark has noticed that the matter and antimatter quarks are decaying in different ways.
You can see the red curve is different for matter B particles (left graph) and antimatter B particles (right graph). This extra time might be the reason why more matter existed than antimatter after the universe had started expanding.
At the moment the data is mostly certain (sigma 3.5) – we need a sigma of 5 for a formal discovery to be published. Sigma is a measure standard deviation, the likelihood of the results being by chance.
- Particle physics has an accepted definition for a “discovery”: a five-sigma level of certainty
- The number of standard deviations, or sigmas, is a measure of how unlikely it is that an experimental result is simply down to chance rather than a real effect
- Similarly, tossing a coin and getting a number of heads in a row may just be chance, rather than a sign of a “loaded” coin
- The “three sigma” level represents about the same likelihood of tossing more than eight heads in a row
- Five sigma, on the other hand, would correspond to tossing more than 20 in a row
- A five-sigma result is highly unlikely to happen by chance, and thus an experimental result becomes an accepted discovery
Happy Tau Day… June 28, 2011
Posted by Mr G in Mathematics, Physics.comments closed
28th of June (6-28 as the Yanks would put it) is Tau day…
What is Tau I hear you ask???
We all know about pi… that number that links the diameter and circumference of a circle. But since we rarely use diameter (we use radius again) we need to add a factor of 2 to all our maths…
e.g.
circumference = 2 x pi x radius
Anything else we do with circles has this extra 2 in it. E.g. Angles in radians – a whole rotation is 2 pi radians.
So along comes Tau where tau = 2 pi
That 2 disappears.
- curcumference = tau x radius
- 1 rotation is tau radians
- Think of the difference that would make to Unit 4 A-level Physics
My New Favourite Space Page May 27, 2011
Posted by Mr G in Astronomy, Physics.comments closed
The APOD – Astronomy Picture of the Day website – is part of NASA. I used to visit this years ago (when I was at Uni… so many years ago – they have an archive going back to 1995)
The page is updated daily – with some stunning images.
Here are a few recent ones – go take a look…
This last shot is the result of the Photopic Sky Survey – 1 man travelling the world taking pictures of the night sky which were then merged into a complete picture. Just cameras and a computer – and very impressive results. Just shows what we could all do…
Mr G
Source: APOD
New sky map most detailed ever! May 27, 2011
Posted by Mr G in Astronomy, Physics.comments closed
The results of the 2MASS Redshift Survey – looking at our local (380,000,000 light years) universe – have been published. This is the most detailed 3D map of our nearest galactic neighbours – with 43,000 galaxies plotted with the correct positions and speeds.
Redshifting is the way in which a galaxy’s light is stretched into longer wavelengths by the expansion of the universe. The farther a galaxy is from Earth, the greater its redshift. By analyzing those measurements, the 2MRS was able to achieve that important third dimension, and to produce the map you see above.
You can get more information from this PopSci article along with a High Res version of the picture..
Mr G
Source: PopSci
Best of YouTube – Issue 1 – April 2011 April 5, 2011
Posted by Mr G in Astronomy, Medicine, Physics, Silly Science, Videos.comments closed
Having been inspired by some of the other blogs I read – I’ve decided to start finding YouTube videos I think show Science in a good light. Hopefully this will be the first of many…
Robot Surgeons
Robots are now dextrous enough to be able to help surgeons perform operations – this one is so good it can be used to make and throw a paper aeroplane.
Northern Lights
Not the book – the beautiful Physics of fast charged particles from the Sun being slammed into the atmosphere along the magnetic field coming from the Earth making the air glow.
The Known Universe
The Universe – as measured and shown as a trip from the Himalayas to the edge of what we know.
Superfluids
Finally a clip from Science@NASA explaining superfluids – where liquids at very low temperatures stop behaving how we expect them to behave – explaining them from an Astrophysics leaning.
Slow Mo Water Balloons
By popular demand…
Mr G
