Eleven-year-olds relate to Einstein

Saturday 4 May 2013 12:38PM (view full episode)

David Blair has been teaching the ideas of Einstein to eleven-year-olds. And they get it!

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Robyn Williams: You're on RN or via your computer or phone, all of which work by using modern physics. But how do we solve the problem of understanding physics? Could you teach primary school kids about Einstein? David Blair says yes, you can. He's a professor at the University of Western Australia.

How do you mean 'teaching Einstein in schools'? Is this to 18-year-olds?

David Blair: No, we actually started by teaching Einstein to 11-year-olds.

Robyn Williams: How does that work?

David Blair: Well, what we think is that there is a big problem in our education system, and the problem can be attributed to Euclid. Euclid published a book which is the most influential science book that has ever existed. It's been in press continuously for more than 2,000 years, and that book has indoctrinated the world in Euclidean geometry, geometry of flat space, geometry of a flat piece of paper.

Interestingly, a very famous physicist, Carl Friedrich Gauss, more than 200 years ago said why should we believe the geometry of Euclid? Why don't we go out there and test it? And he went out and tested it, and, like other unsuccessful experiments, he didn't publish the results, but he surveyed a triangle between three mountains in Bavaria and he measured the sum of the angles of the triangle. He made some beautiful instruments to do the measurement, and he got the result that the sum of the angles was 180 degrees. But he asked the question. And his student was Riemann. Riemann developed the mathematics of curved space geometry, and then Einstein's general theory of relativity said that matter makes space curve and all space in the universe is curved.

So we had this completely different paradigm now. We changed from a paradigm which was the Newtonian paradigm which is that space, time and matter are completely independent from each other, and we changed to a new paradigm introduced by Einstein that matter tells space how to curve.

Robyn Williams: And you're telling this to 11-year-olds?

David Blair: Yes. So we start by telling the 11-year-olds the historical story, let them know about how Euclid's geometry influenced the way people thought and influenced the way Newton thought, led to that idea, and then we tell them the story of the overturning of it through Gauss and then Einstein. But then we take them to actually do experiments with curved space. That's easy. We have two-dimensional curved space easily available at our fingertips anywhere; balloons, curved pieces of an automobile, all sorts of surfaces you can do curved space geometry, as long as you don't work with a piece of paper you find all over the place this curved space.

And you ask the kids; what does a straight line mean? That's actually a very interesting idea as well. Ask kids to think how you survey a straight line. Ultimately they learn that use survey it from paths of light. We let the kids use little laser pointers and they practice surveying straight lines, and then they survey straight lines on curved surfaces. And then we ask them to make a graph of big triangles and small triangles drawn on the balloons and things of that sort. And they find that they have triangles that have 300 degrees, 270 degrees, and the little weenie triangles where the balloon is nearly flat, you get down to 180 degrees.

Robyn Williams: And then they say, 'Teacher, teacher, you were wrong.'

David Blair: Yes, well, they are only at the stage where they are just being taught those formulae of geometry—area equals length times breadth—so that they are only just being introduced to Euclidean geometry at that stage. So what we're trying to do is to say let's think of Euclidean geometry as a convenient approximation but make sure that they enter it with thinking in the modern paradigm that space is curved.

Robyn Williams: And the success, the response?

David Blair: The most interesting response is that the kids are completely unfazed by the whole thing. They don't think this is extraordinary, they don't think it's weird, they just see this as being a perfectly reasonable, natural thing.

Robyn Williams: And of course they've heard of Einstein as well.

David Blair: Yes, but then you can take the story a bit further, you can use a few of the ideas of Einstein's, the idea that falling objects go in a straight line in curved space and takes the shortest path in curved space, and the particular idea, Einstein's idea that freefall paths are the shortest paths in space-time. And what does the shortest path mean? Well, it means something like a straight path of course, we call it a geodesic. And then we say how can it be that an object falling from the Leaning Tower of Gingin, like the water balloons that they drop from the Leaning Tower of Gingin, how can it be that that balloon falls, which is quite a long path in space-time, when it could just stay there and not fall at all? And it doesn't take much logic to realise that that can happen if time depends on height.

So they finally see that the logic of Einstein's theory says that time should depend on height, and then they learn and get to see all the manifestations of curved space that we see around us. They learn that GPS navigators only work because they have to correct for the time difference between the satellite up high and the satellite on the ground, so the clocks are all adjusted. And they also look at lots of images of gravitational lensing in space which gives a vivid view of how space is curved. So they see in real things around them that space-time curvature makes sense. And then of course it's most important that we get them to accept that still the Newtonian ideas are pretty useful, and we talk about the fact that for the next few years most of what you'll be learning will be this old knowledge, but that old knowledge, you have to remember, is an approximation and not the reality.

Robyn Williams: See? So if you are having problems with your relativity or quantum electrodynamics, just ask a school kid in Perth. David Blair is Professor of Physics at the University of Western Australia.


David Blair
Professor of Physics
University of Western Australia
Perth Western Australia


Robyn Williams
David Fisher

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