the Hertzsprung-Russell diagram

Our Sun is a typical yellow star, so its emission would be represented by the middle star in this image.

star_colors
image courtesy of kstars, kde.org – colour is exaggerated

The colour of a star also tells us something about the expected behaviour of a star, it’s lifetime, and destiny.  This is achieved by plotting stars on a Hertzsprung-Russell diagram.  More about HR diagrams here.

This video clip looks at how the stars are arranged on the HR diagram.

Hertzsprung Russell diagram from mr mackenzie on Vimeo.

While some HR diagrams use temperature along the x-axis, others use star classification. 

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100 years of general relativity

einsteinshow.php

It seems general relativity is 100 years old today. We’ve been struggling a bit with this topic, so I thought these videos might help.

Why Einstein is such a big deal from Fusion Media Network on Vimeo.

General relativity explained in under 3 minutes from Fusion Media Network on Vimeo.

Science Museum – Einstein’s Cosmos from ORDER Productions on Vimeo.

#Einstein100 – General Relativity from Eoin Duffy on Vimeo.

star colours

Astronomers often refer to the colour of a star, which seems a bit odd because we mostly see stars as white twinkly objects.  However, even with the naked eye, we can look closely at certain stars and detect a hint of colour – just look at this image of the Orion constellation.  As we view him, the left shoulder has a red coloured star, while the right shoulder and right foot appear to be blue.

320px-Orion_3008_huge

image: Orion 3008 huge.jpg, Wikipedia

Now click on the image to see the same view at much higher resolution.  In the hi-res photo, look at the stars in the background.  They’re not all white!

What can the colour of a star tell us?

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what to do if the website is busy

You might have noticed that the server has struggled to cope with so many people trying to view the resources as the Physics exams approach.

If you can’t get in, you can still access some of the video files and PDF notes through iTunes.

There are iTunes podcasts set up for Advanced Higher, Higher and National 5 Physics.  Those of you sitting National 5 might also find useful resources in the old Standard Grade and Intermediate 2 podcasts.

Advanced Higher podcast

Higher podcast – includes some past papers

National 5 podcast – includes specimen question paper and the 2014 exam, plus marking instructions

Standard Grade podcast

Intermediate 2 podcast

Subscribe to the appropriate podcast and download the pdf/mp3/mp4 files.  I’ve run some tests and this seems to work even when though the site won’t let you in.

viewing the solar eclipse

We spoke about the eclipse in class today.  It’s really important that you follow advice for watching the eclipse safely to avoid permanent damage to your eyes.

You can buy eclipse viewing glasses online.  They look like this

eclipse_glasses

and only cost a few pounds per pair.  Make sure any glasses you buy have the CE mark on them.

Here is one UK retailer of eclipse viewing glasses who still has them in stock.

Although we’re not in the totality (100%) zone, Thurso is well placed to get a good view.  Here is a simulation for Orkney, our view will be very similar.  Click on the picture to start to animation.

Kirkwall_United_Kingdom_2015Mar20_anim

AH uncertainties – post 1

Here is the first of the uncertainty documents to help you with your investigations.

The final page will help you to quantify some of the calbration uncertainties in instruments.  If you use these values, remember to reference Learning & Teaching Scotland as the original source of the booklet.

AH Outcome 3 images

Here are the diagrams you will need for your report. Cick on each link and then save the large image that opens up. You can rezise them once they have been imported into your report.

turntable

stand

radian sector

turntable and stand