How am I doing?

15th July 2016- a special day for Mrs Physics.

I am getting to grips with some of this website stuff and I am thoroughly enjoying putting all the resources together. Today I’ve been trying to put together something for the Road Safety Section. Much of our material is spread over the internet in various places and I would like to collate it all on here. However, I couldn’t understand where some of my posts had gone, but by comparing it to another section of the site I decided I’d got pages up on my menu instead of categories. Hopefully this has been resolved and things are more accessible. I know there is a lot of repeated material. You’ll have to bear with me on that as I get everything together and then present it in a more accessible format.

I hope you are enjoying what I am putting together and can make use of the resources.

Enjoy your summer!

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Blast! That didn’t work. I’ve got the menus, I’ve got the headings, I’ve got the blogs liked to each category- but… they’re not there! I’ll try again.

Never give up, and be confident in what you do. There may be tough times, but the difficulties which you face will make you more determined to achieve your objectives and to win against all the odds. Marta

Me and my calculator

Whilst working with the Police Crash investigator team I had a meeting with Pete Monteith, now known as calculator Pete, whom I decided must be of a similar age to me, as he had the same calculator I’d had at school. The difference was, he was still using his, whilst I was enjoying the delights of an updated calculator.

These days calculators are more technical than the computers I was brought up with. However, I think fewer people know how to use them, which isn’t surprising given the poor quality of the instruction manual. I am on a one woman campaign to get my students to fully utilise this great resource. When I started teaching Physics it used to take two weeks to teach resistance in parallel, now the students are happy in under a lesson- the reason? Their calculators “do as it says on the tin”!

Here are a few things to check out and try. (I am using a Casio, and I know the brighter amongst you would much prefer a Sharp, but I’ve never got on with them). You can draw your own conclusions!

Let’s check out using the calculator how to find total resistance in parallel. The equation is

1/Rt = 1/R1 + 1/R2 + 1/R3… etc.

How can your calculator to do this easily?

Let’s try adding a 7 ohm resistor in parallel with a 28 ohm resistor.

  1. Make sure your calculator is in MATHS IO mode. To do this go SHIFT -> MODE->1. I’ll assume you know to turn it on.
  2. functions
  3. Press the fraction button, two rectangles one on top of the other with a line between. (see image below)
  4. fraction
  5. Now type in the first value which will be 1/7 (7 is the resistance but the equation tells us to find 1/Rt we need to put in the value of 1/R1)
  6. The up and down arrows allow you to move between the top and bottom parts of the fraction.
  7.  arrow keys
  8. Now we need to add the 1/28 to this value. Use the right arrow to make sure that you are out of the fraction.
  9. Press the + symbol.
  10. Then press the fraction button again and add in the 1/28, using the up and down arrows as before.
  11. Now when you press equals you ought to get the answer for 1/Rt, in this case 5/28.
  12. Remember this is not the answer. This is the value for 1/Rt. We need to find 1/ans to find the value Rt. Luckily we have a button for that too.
  13. Press the X-¹ button (see below)
  14. X-1 When you press the equals this gives the answer 28/5. This is indeed the right answer but the SQA does not like you leaving things as a fraction. So press the S<->D button to reveal the answer 5.6
  15. So adding a 7 ohm and a 28 ohm resistor in parallel gives a total resistance of 5.6 ohms.

Yes that really did take nearly two weeks to teach before the age of super calculators.

Remember, your calculator can be a great asset to you during your exam and your career but only if you know how to use it.

Here is another of my favourite buttons, the degrees, minutes and second button.

  1. deg min secWith this button we can easily add times together and convert between time and decimals of time.
  2. For example, we all know that 2 hours 30 minutes is 2.5 hours so we’ll just use this to prove it works!
  3. With this button, you must remember that you have to enter a number for hours, minutes and seconds even if they are not needed.
  4. Enter 2 (for the hours) and press the deg min sec. Then put in the 30 minutes and press the deg min secbutton again.
  5. Now two hours thirty minutes doesn’t have any seconds, but we need to input this into the calculator, so press 0 and the deg min sec
  6. The odd bit, that is easily forgotten, is you now need to press the equals button which reveals 2°30°0°.
  7. Press the deg min secbutton and this gives 2.5. Well we knew that but other numbers aren’t so obvious.
  8. Try 0 hours, 45 mins and 0 seconds. Yes you ought to get 0.75 hours.
  9. But does it work the other way? Yes it does.
  10. Type in 0.75 press the equals and then push deg min sec;the calculator displays 0°45°0° or 45 minutes
  11. You can add time too. Try adding 3 hours 49 minutes to 7 hours 25 minutes. This will tell me the time I will be at Euston Station if I catch the 7:25 train to London, which takes 3 hours and 49 minutes. Now I could just check the timetable or I can use the calculator and I rapidly find I will be in London at 11:14am (or I will if the train is on time: and if it is over half an hour late, remember to reclaim your train fare)

My final fun button that is now a favourite of my classes, although they are right to be a little nervous, if they don’t know what they are doing. These tips cut the time to find resultants or components of vectors and their angles. The teaching of SOHCAHTOA (which incidentally I have to spell out using Six Old Horses, Clumsy And Heavy, Trod On Albert because I can’t spell SOHCAHTOA) appears to have gone by the wayside in Maths. But once you know your Pythagoras and SOHCAHTOAs from other Greek Philosophers then this button can save loads of time, but please don’t use it unless you’re sure you know what you’re doing.

rec to pol

I am sure many of you know that a right angled triangle with sides 3cm and 4cm will have a hypotenuse (or large side) of 5cm, but what will the angle be between the X axis and hypotenuse?

For this we want to use the rectangular to polar coordinate buttons.

rec pol

We want to find the hypotenuse of a 3,4 triangle and the angle it subtends. so therefore we need the Pol button.

  1. Press shift  and then +, this causes a Pol( to appear on your screen.
  2. Enter 4 for along the bottom and then a comma ( which is shift and close brackets) ie shift )
  3. Then add the second digit, the 3 up.
  4. Close the brackets or just press equals.
  5. This gives an r=5, θ = 36.86989765 , which you’d certainly know to round up to 37°.
  6. If you know the 5cm and the angle, just use the Rec button (shift and the minus).
  7. So Rec(5,37) =X=3.99317755, Y=3.009075116, which for a Physicist is fine as 4cm along and 3cm up!

Practice using these buttons and when you need some more handy calculator hints let me know!

To Calculator Pete, if you ever want a race, I’ll time you with your factorial button anytime! When I was at school my Casio beat my friends Texas calculator by about 45 seconds every time I pressed 69 and then the factorial button (!). This then multiplied 69 by 68,by 67 etc. all the way down to 1. Funny, my new super calculator can still only manage factorials up to 69 before running out of digits, but the speed is remarkable. My question to myself, is why did me and my friend Deb Faulder, ever race regularly- as if we expected one day her calculator to beat mine.

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Why electron flow?-Scotland does things differently!

teacher clip art

There was an interesting debate on the Physics forum a few months back about why Scottish school physics went down the electron flow route whereas everywhere else stuck with conventional current.  Well one man, “our man in Aberdeen (as well as all over the place)” has done a great deal or research to get to the bottom of the query. Here is his edited reply.

conventional-current

I have wondered for some time what led to Scottish school physics education going down the electron flow route whereas everywhere else stuck with conventional current.  I had put it down as an outcome of the very significant discussions about the nature of science education and subsequent curriculum development that took place in the 1960s, in much of the western world, initiated at least partly as a result of Sputnik being launched by the USSR.   

Although I have no direct evidence I assume that conventional current was likely to have been used prior to the 1960s.  As I see it there has been four significant periods of curriculum development in Scottish Physics education during the last sixty years.

 1960s

There was the development of the Alternative O Grade and Higher Grade and the introduction of CSYS.  I would wrap up these up with the developments that occurred following the publication of Curriculum Paper 7 and which led to the likes of Science for the 70’s and the Scottish Integrated Science project.  The Alternative O Grade developments ran in parallel and overlapping with the Nuffield curriculum changes south of the border. 

 1980s

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Standard Grade and an applications based approach and the tweaks to Higher and CSYS that followed.  This did a great deal for the popularity and uptake of Physics. 

1990s

Higher Still where the mantra was “minimum change” so the physics did not change much.

 2010s

9781471808258 9781444168549       $_35

(NB Other text books are available!)

CfE (and the Revised courses before) where we have had a welcome refresh of the physics in the Senior Phase .

The move to the orthodoxy (I had better not use the term convention) of using electron flow seems to have been pretty much in place during my own education in the 1970s and certainly by the time I started teaching in the 1980s.  Hence my assumption that it was one of the products of the developments around the introduction of the Alternative syllabuses of the 1960s along with things like tartan trolleys and ticker tape, Westminster electromagnetism kits, Teltron tubes and much else we have become very familiar with since.

 I have done a bit of digging into my archive of publications to see what further clues I can find, but my hypothesis is that the shift occurred not so much with statements in published curriculum documents but in CPD and other activities associated with the implementations, and Jim Jardine’s influence on student teachers at Moray House.

 Here is what I have found.

 SCEEB (predecessor of SQA) First Cycle (S1/2 – and overlaps with Curriculum Paper 7 (1969), Second Cycle – O Grade and Third Cycle – Higher syllabus (1969) and update (1976).

Photos to follow

No mention of direction – all brief statements such as:

p37 Magnetic field of straight wire carrying current.

p37 Force on conductor (qualitative).

SCDS (predecessor of Education Scotland) Memorandum 31 Specific Objectives for Ordinary Grade Physics (1977)

No mention of direction – more specific statements interpreting what was published by SCEEB in 1976 such as:

p16 Recall that the direction of the force on a current-carrying conductor in a magnetic field depends on the directions of the current and the field.

It would appear that there was no preference for either convention in syllabus documents and there does not even appear to be an acknowledgement that two options exist.

 Jim Jardine’s Physics is Fun Book 2 (1964)

Movement of charges, electrons and ions, is well covered in Chpt 2 from p15 but the first signs of electron flow being interpreted as a current appear on p37 in a section titled “Direction of Current”.  “An electric current can be considered as a flow of negative charges (electrons) in one direction or a flow of positive charges in the opposite direction.  We will usually represent it as a flow of electrons, particularly when dealing with electric current in wires.  Black arrows will then be used to indicate flow of electrons.  When dealing with the movement of positive charges arrows will be coloured red.”

Figure 89 then shows a circuit with black arrows on the wires labelled electrons indicating a current in the circuit.

In Physics is Fun Book 4 (1967) p58 the section uses black print to show streams of electrons in the case of magnetic fields around conductors.

Jim’s NatPhil ‘O’ (1973) continues to use the black and red two colour approach but there is definitely less of the red and in figures such as Fig12-4 on p109 it would be very easy just to interpret a current flowing negative to positive and to lose the distinction very clearly made in the Physics is Fun books.  On p120-1 in the magnetism section reference is made to both positive charges and electrons and Fig 13-28 is of Fleming’s Motor Rule using conventional current.  On p123-4 both black and red are used but the black dominates in appearance.

Nuffield Teachers’ Guide II (1966)

As part of a section dealing with the teaching of electricity the following appears on p40 “So far….we have not bothered very much with the direction of current.  In future we shall adopt a universal agreement made a century ago.”  All the Nuffield materials then go on to use conventional current but at times mentioning how electrons move as appropriate. 

Science for the 70’s Book 1 (1971) on p111 in Unit 7 makes the statement “The electrons flow out along the wire connected to the negative terminal of the cell.”  Otherwise the discussion is about relative brightness of lamps.  However, in the Teachers’ Guide on p138 there is the Specific Objective:

“…the pupil should acquire:

2. the knowledge that current in a solid conductor is regarded as being a flow of electrons,”

In Science for the 70’s Book2 (1971) on p111 Figure 15.15 and the surrounding text uses conventional current to determine the direction of the magnetic field around a current carrying conductor.  However, I very few people ever had enough time to reach Unit 15 in the time available for science in S1/2.

In the Scottish Integrated Science Worksheets and Teacher Guides (1977) there is no specific directionality on diagrams etc but in the Teachers’ Guide Sections 1 to 8 on p131 the Section Objective:

“All pupils should acquire:

2 the knowledge that current is a flow of charge (electron)”

There is also a recommendation to use the symbols and practices in SCDS Memorandum 5 Symbols and Terminology in Physics (Second Edition) (1975).  Although this lists the conventions for writing quantity symbols and units and circuit symbols there does not appear to be any recommendation on current direction.

Cackett, Kennedy and Steven’s Core Physics (1979) on p184 it states “When we describe current in our circuits, we will be referring to the movement of electrons and this direction will be from negative to positive.  In some textbooks the current is described as flowing from positive to negative.  It is then often referred to as ‘conventional current’.”  Arrows labelled I are then shown in subsequent figures in both circuits and magnetism sections.

Alistair Reid’s O-Grade Physics (1980) book current arrows on circuit diagrams going from negative to positive and the right hand rule in the magnetism section.  I cannot see any reference to conventional current or electron flow it appears to just assume current is negative to positive.

David Standley’s SCE O Grade Physics (1983) book explains both conventional current and electron flow on p163 with a helpful diagram showing a conventional current arrow on the circuit wire and an electron flow arrow separate from the wire and avoids using direction arrows on figures.  Conventional current is consistently used in the magnetism section (I might add that David taught in an independent school which also taught English syllabus courses which I am sure at least in part accounts for the difference in his approach).

So in conclusion, I think I have confirmed my hypothesis.  Between the early 1960s and the early 1980s none of the syllabus or guidance documents state a requirement for one convention or another.  However, following the lead taken in Jim Jardine’s Physics in Fun books the emphasis was increasingly placed on electron flow in metal conductors.  Although Jim makes the distinction very clear in his early texts this is less so later on and in subsequent texts published by others in Scotland the idea that current is a flow of electrons becomes dominant.  I suspect that by that time the subtle distinctions and teaching points that I am sure were discussed and considered very important by the committees involved during the development of the likes of the Alternative O Grade and Nuffield resources were forgotten in the mists of time.  I suspect there must also have been CPD available when the Alternative Physics and Integrated Science courses were introduced that also promoted the use of electron flow.  Hence we arrived at a point when I entered teaching that Scottish physics teachers just accepted currents in school physics as electron flows because “that was the way it is” without necessarily appreciating the underlying philosophy – it might even be an example of “group think”.  

Our Man in Aberdeen and all over the place is Stuart Farmer. Head of Physics, Robert Gordon’s College, Aberdeen, United Kingdom. He has been awarded the 2016 Bragg Medal and prize of the Institute of Physics. He has been a member of the Association for Science Education (ASE) since he started teaching and has been its Chair of Trustees as well as Chair of ASE Scotland three times.  Stuart is the Vice-chair of the Institute of Physics (IOP) in Scotland, a member of IOP’s Scottish Education Committee and the IOP’s Teacher Network Co-ordinator for Grampian and the Northern Isles. 

You’re never stupid!

I really ought to be stopping for the evening, especially as I spent the day in A&E. What was particularly embarrassing was that I went there to support a relative, only to need a bed myself as I passed out! Thanks to those wonderful people in A&E at DGRI who never made me feel stupid. Anyway talking of stupid, here are two documents to get you thinking. The first is a little old. The 1927 Solvay Conference. Imagine being a fly on the wall at that event. Actually most of it would probably have gone over my head or under my wing. The other is a more up-to-date document, a survey from the IoP (Institute of Physics) suggesting that those with a degree in Physics will likely be able to earn more than the average salary.

Physics in Scotland Physics Graduates are more likely to earn more than the average salary, so it is worth persevering!

The Solvay Conference 1927.pdf A meeting of the brightest minds. How many have you heard of? Notice there might only be one woman but she won Nobel Prizes in Physics and Chemistry so that’s something. Don’t give up as a woman and think Science isn’t for you. You can really make a valued contribution.

The Solvay Conference 1927.docx

Maybe one of you will be this amazing, or maybe you are already. I know I am not!

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The People behind Scottish Physics

IoP Physics Coordinators
IoP Physics Coordinators

I don’t mind pinching things when they’re great and this has been adapted from a post on SSERC’s facebook page. The physics education community in Scotland owes a great deal to these people – the IoP Scotland network coordinators and education manager. Left to right: Tom Balanowski, Gordon Doig (Education Manager), Nick Forwood, Drew Burrett, Ronna Montgomery (Leader of the Pack), Brian Redman (“Mr Sputnik”) and Stuart Farmer. Scottish physics teacher cannot overstate how much they have contributed to Physics education in Scotland.

Teachers should also thank the Magic Pixies aka Nick Hood for hosting Physics resources during these times of huge upheaval and change in the Scottish Education System. Without this facility I think many Physics teacher would have “gone under”, which is somewhere near where the Pixie was last seen!

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Lastly SSERC is “on the edge, but in the middle” of Science Education in Scotland. They keep Physics teachers up to date, trained and inspired. Firstly it was Jim Jamieson and then Gregor Steele with a whole host of other support staff (e.g Ian, Graham, Gerry, Catherine etc.).

Just know that you’re appreciated!

My thanks to you all.

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Time consuming

As I’d sent my postal vote away already I had time on my hands! Well I had another go at the website when ex-pupil came and inspired me again. I am so desperate to get things up on the site, but I am currently struggling with the demands of the day job. Physics teachers, especially those in Scotland are the most generous people I know but there is still quite a lot required of a single Physics teacher in Science Faculty when other teachers are going to have to teach your subject. Please be patient, and hopefully over the long summer, when the rain starts and the house is tidy I can really make this site interesting. For now just watch the paint dry.

Love this joke on sputnik.

Why are protons always positive?

Because they are more up than down.”

It’s great to have an in joke. If you don’t get it watch the video below!

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One week on…

Well the website is just over a week old and it now has 6 parts. I’ve put in my first pictures and links and made logos. I’ve not got the hang of uploading everything as I keep getting http error messages and I haven’t got it to look good yet, but I feel I’ve learned quite a lot. Wish I knew how to make the calendars a little smaller, but those finer details can come later. I wish I was competent and knowledgeable about making a website. I don’t know if trial and error or a good read first is what is required!

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