Science

Knowing the word for something and having an understanding of it are not the same thing

It ain’t what we don’t know that gives us trouble, it’s what we know that ain’t so.”
Will Rogers
 A common failing in all levels of science education is mistaking having a word for a phenomenon with having an understanding of it.

 

To take a very simple example, if I ask any of my students why the apple falls ‘down’ from the tree they will all say ‘because of gravity’.

If I then ask them what ‘gravity’ is I get a lot of mumbled responses before they finally acknowledge that they have to idea.

I don’t either.

Neither did Newton.

Scientists still don’t.

Or I could pose the following:
My book is sitting on the table. There is a force of gravity acting on it pulling it downwards.
The fact that it doesn’t fall downwards must mean that there is another equal force acting upwards.
So, I ask, what is this force?
“That’s easy”, say the troops, “it’s the table.”

But a table isn’t a force, I reply – a table is a table.

It gets better. Let’s assume that the weight of the book is one Newton.
Whatever is acting upwards (opposing the gravitational force) must therefore also be one Newton.
Now if I put a heavier book on the table (two Newtons in weight) the table now needs to push back upwards with an equal force of two Newtons. How come the table ‘knows’ exactly the right amount of force to push up with?

It’s obviously a very clever table.

What happens if it got its sums wrong and pushed up with a force of three Newtons when it should have just pushed with two Newtons?
Hmmm . . .
force-on-a-book
In our Physics and Applied Maths classes we do lots of calculations with this upward force. And because we talk about it so much we gave it a name. It’s called a “reaction” force, signified by the letter R (because we’re nothing if not imaginative).
I use this as an opportunity to predict the future career path of the students in front of me. Engineers are perfectly happy not to know anything about the origin of this reaction force. I just need to get out out of their way while they get on with the business of using it to get the right answer.
The physicist is the guy/gal who knows there is something odd about all this and isn’t happy until they get to the bottom of it.
The dilemma I constantly struggle with is the following: how much time should I spend  trying to unravel students’ misconceptions in order to give them a deeper understanding of the basic concepts when the exam is just looking for superficial answers.

So more and more I put my emphasis on the wonder of the subject. Because that’s what drew me into it in the first place, and then gradually I sorted out some of these issues myself. But I still still struggle with most of them. But it’s a wonderful struggle.

 

So don’t worry if students at any age don’t have a fully-worked out understanding of what’s happening. Once they’re happy to ask questions, and the environment is there to encourage this, everything else will follow in its own good time.

At least that’s what I think.

I could well be in a minority of one . .

Aims and Objectives? I have but one: see science as a source of wonder

This is to serve notice that I am changing the Aims and Objectives of my Leaving Cert Physics subject plan.
The existing plan was cobbled together at short notice by copying and pasting from other schools courtesy of some nifty google searching.
But it’s pretty bland and therefore not really fit for purpose.

So what are my objectives?
Actually, there are very few:
I simply want students to appreciate science as a source of wonder.
Science, to paraphrase Feynman, does not diminish our sense of wonder – it can only enhance it.

Feynman: wonder in ScienceI want students to see science as a cultural activity – it is an integral part of what it means to be human.

The awed wonder that science can give us is one of the highest experiences of which the human psyche is capable… to rank with the finest that music and poetry can deliver.
Richard Dawkins

Science represents the best and worst of what humanity is capable of. We celebrate literature, poetry, art, dance, music as aspects of culture. We need to see Science in the same light.
And we need to stop portraying it as all good. Because it’s not. We’re on a one-way ride to global catastrophe as a result of global warming. It may well lead to the extinction of the human species in the not too distant future. And I’m pretty sure this wouldn’t have happened without Science and it’s hand-in-hand link with uncontrolled capitalilsm. But you’re not likely to see that in any school textbook.

Science tells us as much about where we have come from as it does about the world we inhabit. This must not be downplayed. In this context psychology is probably the most important of all the sciences and it is deeply unfortunate that psychology plays no part in traditional school science.

I want students to appreciate that Science not merely an accumulation of facts. The picture we portray of it in school is therefore not only incorrect but totally at odds with reality.
We should all apologise to our students for this.

Science is built of facts the way a house is built of bricks: but an accumulation of facts is no more science than a pile of bricks is a house
Poincare

Do I want my students to go on and become scientists?
Not in the slightest. If they do then good luck to them, and I will help them if I can, but it’s not a priority. Does anybody seriously think that being a scientist is somehow any more noble than being a writer or a poet, an accountant or a tax official? How about a lawyer? Or for that matter a teacher?
So why should I push them in a specific direction?

Do I want to re-dress the gender balance?
Not for its own sake, no. I would like as many students as possible to appreciate the wonder of science, but I can understand why lots of girls are reluctant to take on Physics and/or Applied Maths as they are currently presented and I can’t say I blame them. Sticking up posters of token female scientists isn’t going to have much of an effect either, so please stop sending them to me.
If I’m being very honest what matters most to me is that we have enough students to justify two physics classes and one Applied Maths every year.
We get on average 40 – 45 students taking on Physics and anywhere from 15 – 24 taking Applied Maths.
So I’m happy on that score.

Do I think my students are going to become better citizens, or more informed in relation to science controversies than students who don’t do Science?
Not a hope.

Am I interested in how the students do in the Leaving Cert exam?
Yes, but really only in the sense that it’s all a game. And it’s not even my game; it’s their game.
But if I want them to play my game then it’s only fair that I play their game.

So I take both the syllabus and the past-papers apart and base the main section of my notes just on these.
And then I go off on all sorts of tangents based loosely (sometimes very loosely) on the topic at hand. But then when I’ve finished I go back and cross-check what I’ve done against the syllabus and questions from past papers and pick up the pieces that way. And I teach it just about as well as I possibly can.
I do appreciate that there are students in my class who are looking for an A1 and I know that I need to facilitate them as part of my bread-and-butter duties. And I’m happy to do so.
But I don’t stress over it. Once the students walk out of my class for the last time in May I wish them well but then take the stance that my job is done. So I don’t look at their results. In fact I believe strongly that this is actually a dangerous thing for any teacher to do. I accept that I’m in a minority here but I don’t need to see the students’ leaving cert results to find out whether or not I’m doing a good job. There are any amount of ways to find that out throughout the year, and adapt accordingly.

So that’s it.
Those are my aims and objectives or whatever the buzz phrase is these days. I see no reason to change this just for inspection purposes. If that makes me a ‘bad’ teacher in some folks’ eyes well, I guess I can live with that too.

For more recent blogposts on wonder in science see this link

antimatter

http://smbc-comics.com/index.php?db=comics&id=2088#comic

What do you do when Science equipment breaks down?

Question:
How do you tell Biology from Chemistry from Physics?
Answer:
It it wiggles it’s Biology, if it smells it’s Chemistry and if it doesn’t work it’s Physics.

I don’t know of any teacher-training course which spends time training teachers on the finer points of being a technician. Yet when equipment does break down you’re expected to somehow just ‘know’ what to look for – and how to fix it.

Even better, if you’re the Physics teacher then you automatically become the ‘go-to’ guy (or gal) for colleagues (and not just Science colleagues) when they have something which needs fixing.
If you’re replacing somebody who just retired then the chances are good that this person is not going to come back in to help you become familiar with what does and doesn’t work. It’s quite possible that you’ve never even met this person, so you’re likely to spend the next few years finding pieces of apparatus in shelves without having any clue as to what their function is.
As a result the shelves in our labs are full of expensive equipment that just sits there gathering dust.

So what do you do when something breaks down?
One option which many are not aware of is to ring up your supplier of school science equipment and ask them if they can fix it. Many of them do have repair departments and should be able to give you a quote which you can then compare to the price of a replacement.
Another option is to ask a senior class if anybody there wants to have a look at it. Usually you will find somebody there who has more free time than you do (but obviously don’t allow them play with anything that could have health and safety implications).

Everything a Primary School teacher (or student) needs to know about gravity. And then some.

This post is in the context of a question posed by a primary teacher on a forum recently. Rather than reply there I thought it safer to do so where I could offer a more comprehensive answer.

We tend to associate the concept of gravity with the English scientist Isaac Newton who lived in the seventeenth century.
But he didn’t ‘invent’ gravity; objects were falling to earth long before Newton arrived on the scene, so what exactly did he do?

1.
He did what so many other kids do; he asked asked a silly question. ‘Why do things fall down?’
It does seem like a silly question, which is why nobody took it seriously before, but when you think about it it’s actually quite profound; how does the apple in an appletree ‘know’ which way to fall? How does the earth ‘know’ (if it pulls the apple down) that the apple is there in the first place ? Newton was never able to answer that question. He famously said  “Hypotheses non fingo” (Latin for “I feign [frame] no hypotheses,” or in other words, “I haven’t a clue why this works the way it does”). It’s not like there’s a string connecting the two objects, but yet the apple acts as though there were indeed an invisible string pulling it downwards.
What form does that invisible string take?

I don’t know the answer, but I do know that scientists haven’t fully worked it out yet either.
It has been suggested that all objects exchange particles called ‘gravitons’ and it is as part of this exchange process that the objects come together. The problem is that these gravitons have never been detected.

Another possibility is gravitational waves. These were postulated by Einstein in his Theory of General Relativity. There has been some indirect evidence for these but again they haven’t yet been detected directly. We know we don’t know all there is to know about gravity, and to suggest otherwise would be to do a disservice to your students. In fact the same holds for a lot of science. Gravity does seem to be a little like magnetism, yet the rules which govern gravity don’t work for magnetism and vice versa. The holy grail of physics is to show how the rules that govern the motion of very large objects like planets is connected to the rules that govern the operation of very small objects like atoms. And there’s absolutely no reason why one of your students can’t be the one to make this connection and win their very own Nobel Prize (with a bit of luck they will acknowledge  you  in their acceptance speech as the spark which ignited their passion for Science).
Matthew is a former student of mine and is currently doing a PhD with NASA on this topic. I asked him to explain it to me:

“In the Einsteinian framework, however, gravity is not a force but a curve in space-time. So any object with mass induces a curve in the spacetime around it. Any other object no longer travels along a flat spacetime, but along a curved path. That’s essentially what’s happening to the apple. Instead of hovering at the end of the branch as it would in a flat spacetime, the ‘forward direction’ of spacetime is curved due to the Earth, so the apple just follows that curve, which in three spatial dimensions is just a straight line down.”

Watch the following clip for a wonderful demonstration of a curving space-time –  imagine doing this with your kids in class: you can tell them you are studying Einstein and doing Rocket Science.

But while Newton couldn’t say why gravity worked, he was able to quantify the force of gravity, i.e. he was able to devise a formula which now enables us to say how big the force of attraction will be between any two objects. It depends on how big the objects are (or more specifically their masses) and the distance between them.

It turns out that any two objects will exert a gravitational pull on each other. Now this is mad. It means that there is a force of attraction between you and your biro, and if it was just the two of you floating in space with no other objects or planets in existence, that force of attraction would result in the biro moving towards you and you moving towards the biro. Similarly there is a force of attraction beween each student and the student next to them (cue lots of giggles) and the bigger the size (or mass) of either student, the bigger will be the force.

2.
Newton also established that the force that kept the planets in orbit around the sun was the same force as that which pulled the apple to earth. This idea was a big, big deal at the time. It meant that the planets followed the same laws of physics as objects on earth. Prior to this ‘the heavens’ were thought to be the realm of the gods or God and therefore not subject to our analysis but after Newton they were seen as fair game for anybody to study. I don’t think there’s any way we can really appreciate how big a deal this was. And while Newton wasn’t the very first to realise this, he was the first to demonstrate it mathematically.

The following is a nice video which outlines the significance of Newton and Einstein to our understanding of gravity. You only need the first ten minutes.

The bottom line for me is that you have an incredible audience who will lap this stuff up. Please, please don’t play down the mystery or the wonder. That, unfortunately, is what happens at second level and I have been trying to get teachers to fight it my entire professional career, with very limited success (it doesn’t seem to bother many other teachers, but I have it bad).

Don’t allow your lack of technical knowledge to put you off engaging with the material. Remember when it comes to Science nobody, and I mean nobody, has all the answers. If we’re looking to turn some of these kids into scientists then what they need more than anything else is curiosity and a good old-fashioned sense of wonder. If you can help develop that then everything else will follow.

There’s that word again . . . WONDER

Students today are often immersed in an environment where what they learn is subjects that have truth and beauty embedded in them but the way they’re taught is compartmentalised and it’s drawn down to the point where the truth and beauty are not always evident.

It’s almost like that old recipe for chicken soup where you boil the chicken until the flavour is just . . . gone.

I have this video numerous times but it was only when I watched its creator David Bolinsky talk about it on TED that I heard that powerful word again: Wonder.

Here’s another take on it, this time from Simon Jenkins in the Guardian

I devour popular science, finding its history and its wonder a constant delight. . . . It is a mystery how so many science teachers can be so bad at their jobs that most children of my acquaintance cannot wait to get shot of the subject. I am tempted to conclude that maths and science teachers want only clones of themselves, like monks in a Roman Catholic seminary

Or how about George Monbiot:

We are deprived by our stupid schooling system of most of the wonders of the world, of the skills and knowledge required to navigate it, above all of the ability to understand each other. Our narrow, antiquated education is forcing us apart like the characters in a Francis Bacon painting, each locked in our boxes, unable to communicate.

This one is mine – maybe we should form our own society!

We educators take this incredibly exotic jungle of knowledge called Science and distil it until all the wonder has been removed and we are left with nothing but a heap of dry shavings. We then pour this drivel into our syllabus and textbooks and make our students learn it off by heart so that it can all get vomited back up come exam time.
And then we wonder why so many young people don’t like science.

It’s really such a shame that the wonder of Science only seems to be spoken about by artists, poets and writers. Why do scientists (and science teachers, and in particular those who are responsible for drafting the science syllabi) hide from it so much?

Would they not accept that by acknowledging the Wonder that lies at the heart of the subject we might actually engage the students a little more? Maybe it goes right back to the origins of Science.  Adam Smith once wrote that “Science is the great antidote to the poison of enthusiasm and superstition” and the philosophy behind the world’s first scientific society was to discover knowledge, not by force of argument or flowery speech, but rather as a result of cold, objective facts (hence the gradual removal of the use of the first person singular when describing experiments and the move towards the more impersonal ‘the experiment was set up as seen in the diagram’).

What a disservice we do to our students.

Naming of Parts, by Henry Reed

One poem that I particularly like (and have hanging outside the door of my lab) is “Naming of Parts” by Henry Reed; it contrasts a lesson in military weaoons with a flowering plant.
My classroom looks out on a flower garden and I often think of this poem as I spot another student gazing wistfully out the window as I waffle on about the finer points of electromagnetic induction.

Naming of Parts

Today we have naming of parts. Yesterday,
We had daily cleaning. And tomorrow morning,
We shall have what to do after firing. But today,
Today we have naming of parts. Japonica
Glistens like coral in all of the neighboring gardens,
And today we have naming of parts.

This is the lower sling swivel. And this
Is the upper sling swivel, whose use you will see,
When you are given your slings. And this is the piling swivel,
Which in your case you have not got. The branches
Hold in the gardens their silent, eloquent gestures,
Which in our case we have not got.

This is the safety-catch, which is always released
With an easy flick of the thumb. And please do not let me
See anyone using his finger. You can do it quite easy
If you have any strength in your thumb. The blossoms
Are fragile and motionless, never letting anyone see
Any of them using their finger.

And this you can see is the bolt. The purpose of this
Is to open the breech, as you see. We can slide it
Rapidly backwards and forwards: we call this
Easing the spring. And rapidly backwards and forwards
The early bees are assaulting and fumbling the flowers
They call it easing the Spring.

They call it easing the Spring: it is perfectly easy
If you have any strength in your thumb: like the bolt,
And the breech, and the cocking-piece, and the point of balance,
Which in our case we have not got; and the almond-blossom
Silent in all of the gardens and the bees going backwards and forwards,
For today we have naming of parts.

I posted this on a Physics teachers’ forum a number of years back and one reader was so impressed by the poem that she immediately adapted it to her own lesson. I obviously wasn’t the only admirer of her work – the adapted poem appeared in the journal “Physics Education” shortly afterwards. I haved included it here with the kind permission of the author.

Induced emf

Phoebe Wales

To-day we have induced emf. Yesterday,
We had motor effect. And to-morrow morning,
We shall have eddy current braking. But to-day,
To-day we have induced emf. Japonica
Glistens like coral in all of the neighbouring gardens,
And to-day we induced emf.

This is the flux density. And this
Is the flux, whose use you will see,
When you differentiate it with respect to time. And this is the cosine of the angle,
Which in your case you don’t need to do. The branches
Hold in the gardens their silent, eloquent gestures,
Which in your case you don’t need to do.

This is Lenz’s law, which is just an addition
To what Faraday had already said. And please do not let me see
Anyone using the wrong units. You can derive them quite easily
from SI units. The blossoms
Are fragile and motionless, never letting anyone see them
Using the wrong units.

And this you can see is how quickly flux changes. The purpose of this
Is to calculate the emf. We can apply it
To an isolated wire: this creates
A pd between terminals. And rapidly backwards and forwards
The early bees are assaulting and fumbling the flowers:
A pd between terminals.

They call it Fleming’s right hand rule: it is perfectly easy
If you have any spatial awareness: take your right thumb,
And first finger, and second finger, and the directions they point,
Clearly give you the answer; and the almond-blossom
Silent in all of the gardens and the bees going backwards and forwards,
For to-day we have induced emf.

The Two Cultures – why our schools are to blame

When I Heard the Learn’d Astronomer

By Walt Whitman

When I heard the learn’d astronomer,
When the proofs, the figures, were ranged in columns before me,
When I was shown the charts and diagrams, to add, divide, and measure them,
When I sitting heard the astronomer where he lectured with much applause in the lecture-room,
How soon unaccountable I became tired and sick,
Till rising and gliding out I wander’d off by myself,
In the mystical moist night-air, and from time to time,
Look’d up in perfect silence at the stars.
Scientists often complain about how they are perceived in literature. It seems as though the battle – with writers, poets and artists on one side, and scientists on the  other – has been going stong long before C.P. Snow wrote about ‘The Two Cultures’ back in 1959.
It was a strong theme all through the Romantic era and more recently prompted Richard Dawkins to write an entire book on the subject.  His take on it was similar to that of Richard Feynman; far from taking from the wonder of the subject, science actually adds to it. We can still appreciate the beauty of nature while having a deeper understanding of the reason nature is the way she is. Dawkins’ booktitle was a reference to a Keats poem about the wonder of rainbows, but it’s not an uncommon complaint; Richard Feynman says something similar about a simple flower.

What I find fascinating is that neither Feynman or Dawkins (or indeed C.P. Snow himself) seem to wonder why many artists have such a poor view of science. Walt Whitman’s poem above seems to be a fair reflection of how scientists in general are viewed by  the public at large.

For me, this poor image of Science (and scientists) is generated in school. The textbooks are terrible, the syllabus even more so, and it is only the enthusiasm of the odd teacher that creates any sort of positive image of the subject. It seems to me that science teachers at secondary level and lecturers at third level do very little to inspire wonder in any student who isn’t already fascinated by the subject. I have said it on many occasions before; when you consider the enthusiasm of students for the subject when they first encounter it in first year, and contrast this with their weariness for the subject in sixth year, it’s a wonder any of them choose to keep it on at third level. Of course the pigeon-holing of all knowledge into outdated compartments called ‘Subjects’ may also have something to do with this.

And unfortunately all the Science Weeks and Science Gallaries and Cities of Science in the world won’t change this.

What might result in change is if more attention was paid to our abysmal syllabus by some of these folk who are so heavily involved in promotion of science ourside the classroom; perhaps if enough artists and writers addressed this issue . . . a new romantic movement anyone?

Thanks to my colleague Mr Devitt for reminding me of the Walt Whitman poem. Young Devitt is one of those indivuals who is as happy talking Physics/Science as he is talking History (his trade). I am fortunate in my school to have a number of such colleagues, but as with teachers  everywhere else there is just so little time or opportunity to allow for cross-pollination of this sort. What I find fascinating about discussions with colleagues from the humanities side of the fence is that they always seem to have more of a sense of wonder for the (science) ideas than do my science-teacher colleagues. I don’t know why that is.