Derek Raine
HEG Oct 2011
Misconceptions
Examples
The
project
Your input
The vision
Beautiful Railway Bridge of the Silv'ry Tay!
Alas! I am very sorry to say
That ninety lives have been taken away
On the last Sabbath day of 1879,
Which will be remember'd for a very long time.
'Twas about seven o'clock at night,
And the wind it blew with all its might,
And the rain came pouring down,
And the dark clouds seem'd to frown,
And the Demon of the air seem'd to say"I'll blow down the Bridge of Tay."
When the train left Edinburgh
The passengers' hearts were light and felt no sorrow,
But Boreas blew a terrific gale,
Which made their hearts for to quail,
And many of the passengers with fear did say"I hope God will send us safe across the Bridge of Tay.“……
Shall I compare thee to a summer's day?
Thou art more lovely and more temperate:
Rough winds do shake the darling buds of May,
And summer's lease hath all too short a date:
Sometime too hot the eye of heaven shines,
And often is his gold complexion dimm'd;
And every fair from fair sometime declines,
By chance or nature's changing course untrimm'd;
But thy eternal summer shall not fade
Nor lose possession of that fair thou owest;
Nor shall Death brag thou wander'st in his shade,
When in eternal lines to time thou growest:
So long as men can breathe or eyes can see,
So long lives this and this gives life to thee.
Misconceptions - scales
This misconception is that atmospheric pressure decreases because gravity gets weaker
with height above the earth. The misconception is not that gravity gets weaker as you go
away from the earth – it does – but that is not why atmospheric pressure diminishes with
height.
Misconceptions - idealisations
The momentum, p, of a particle confined to an infinite square well is uncertain even in a definite energy level. Therefore
the energy p2 /2m must be uncertain. But the particle is in an energy level. So the energy cannot be uncertain
We’re saying that on the one hand the total energy of a particle inside an infinite square well is p2/2m because the
potential energy is zero. Thus either both the energy and momentum have definite values or they are both uncertain.
But we know that neither is true: the energy is certain but the confinement of the particle to a finite region of space
means that there is a finite uncertainty associated with the momentum. This is more a paradox than a misconception:
the resolution is quite subtle.
Misconceptions - language
The misconception that human error is a source of error is something that drives professional
scientists mad. The problem is the misuse of the technical notion of error for its everyday
meaning. Error (in the technical sense) in science is not a synonym for a mistake; error (in the
technical sense) is not avoidable by any form of human action: it is unavoidable because of the
way that the world is. Let’s see how this comes about.
Misconceptions - Maths makes it harder
In this physics piece we’re going to look at an example of how doing the right algebra
can help us understand a phenomenon. The problem is to estimate the rise in sea
level resulting from a 1 degree rise in sea temperature, the increase in height being
brought about by the expansion of the water.
Either:
4
π (R +
3
H '=
(
H ' ) 3 − 43 πR 3 = (1 + α ) 43 π ( R + H ) 3 − 43 πR 3
( π (1.000207 × ( π (6378100 + 3720)
3
4
4
3
3
)
))
− 43 π (6378100) 3 + 43 π (6378100) 3
Or:
Expand by the binomial theorem:
H ' = (1 + α ) H
independent of the radius of the Earth!
)
1/ 3
− 6378100
And understanding the maths makes it easier:
This is an example of a problem that seems difficult if you try to argue it in words, but
becomes quite simple if you allow the maths to do the work. The two potential wells
have equal depths but different widths. Which of them has the lower quantum
mechanical ground state energy?
To enhance the learning of students in
University Physics programmes by improving
their conceptual understanding
Collation and development of resources for testing
conceptual understanding (Concept Inventories) –
Edinburgh (Simon Bates & Ross Galloway) and St
Andrews (Antje Kohnle)
Identification of threshold concepts and misconceptions
(You)
Production of materials on misconceptions, conceptual
understanding and the interpretation of equations -
Leicester
Modelling workshops for students – Hull (David Sands)
Concepts through experiment - Durham (S Nolan & L
McComb)
McComb)
Concepts through Data analysis – Hertfordshire (Nikhil
Thilakan,
Thilakan, Balu Govind & Jim Collett)
University of Hull (D Sands (Co-PI), T Overton)
University of Leicester (G Wynn)
University of Durham (L McComb, S Nolan)
University of Hertfordshire (J Collett)
University of St Andrews (B Sinclair, A Kohnle)
University of Edinburgh (S Bates)
University of Glasgow (M Casey)
University of Bath (F Laughton)
IOP (Peter Main)
In groups (e.g. pairs) come up with
a common student misconception
a point where maths aids understanding
Concept testing
– starting from where students are
Support materials
- the “audio “book””
Material delivered to student need
via
The e-library
Material in various formats - e-books, audio,
screen-casts, simulations, …
Reduced emphasis on lectures
More student contact
Evidence-based teaching
•Communicate some misconceptions
•Recommend (or offer) good multimedia resources
for specific concepts
•Offer to trial material
•Join the forum
http://physics.le.ac.uk/concepts/phpBB3/