Why do we teach lies at school?

I learned something interesting recently about gravity. Well, it's something I'd heard before plenty of times but, a bit like how it took reading The Selfish Gene to really understand evolution, it wasn't until I read Why does E=mc2? by Brian Cox and Jeff Forshaw that I got a glimpse (it's more difficult to understand than natural selection) of what it means when people talk about gravity and 'curved spacetime'.

This post isn't about the subject matter of the book, as such, rather what it got me thinking about some of the things that are taught to children in school (I'm currently training to be a primary school teacher, so this is a significant question for me). But I should explain the basic principle so you know where I'm coming from.

One of the last chapters in the book describes gravity as something we observe which hints that spacetime is curved. To do my best to explain briefly, let's first think about forces. There is a law that we're all probably familiar with that objects will remain at a constant velocity (either sitting still or coasting along) unless a force acts on them. To persuade yourself of this, just think how obvious it is that an object won't spontaneously start moving without a force. Then you only need to realise there's no difference to Nature between sitting still and moving without accelerating. So it turns out that the deeper rule is that an object moving at constant velocity won't spontaneously accelerate (imagine a world without friction, there'd be no way to stop unless you hit something!).

So, to gravity. Gravity is taught as a force because objects tend to fall and it looks as if they're being pulled away from what would have been their natural course, just as if a force were acting on them. Certainly a constant downward force would have the same effect on an object in space. But in the book it is revealed that our best understanding of physics describes the natural course of objects to be along straight lines through spacetime, spacetime which is curved by the presence of mass. So an object you're holding in your hand would coast along a straight line through space time that would bring it closer to the Earth, if you let it go. You're constantly bumping against its spacetime-momentum, like you would bump against someone if you tried to walk in a straight line parallel to each other due to the curvature of the Earth's surface. It's not that you're attracted to each other, it's that your paths intersect.

In other words, gravity isn't a force. This is crucial, because it is explicitly described as a force in primary science. Watch this (brilliant) video I found of Dr Richard de Grijs teaching primary school children about gravity. I'm sure he's heard of Einstein, so why is he teaching children that gravity is a force? Perhaps, I've been thinking, he shouldn't be...

I am still finding a lot of the concepts (pretty much anything to do with movement through spacetime from multiple perspectives) in Why does E=mc2? to be very hard to focus on and I strongly suspect this is because it contradicts what is drilled into our heads in school. What sort of obstacles are we putting up with miseducation like this?

We don't have to teach children advanced physics, obviously, but should we teach them lies? Why do we still teach children that gravity is a force, if we know it's not? Is it really necessary? Surely it would, if nothing else, be better to just avoid discussing it, as we avoid discussing the relationship between magnetism and electricity, if there's really no way of describing it to them. Then when they're older they won't find it such a hurdle to wrap their head around the actual theories we use to understand Nature.

And perhaps it is possible to teach children the rudiments of these things. Isn't the point of the curriculum to work out the best way to break down complicated subjects into steps that children can handle? Is it really more complicated than other scientific concepts, or is it a very new way of understanding Nature?


  1. I've always had a problem with the "they're teaching us lies" mentality when people discover there is more to things than simple models.

    Science is about modelling the universe, testing the models and discovering things about the models, the consequences of them and finding where they break down.

    I would refute that "gravity is not a force", there are multiple models for the interactions of mass and teaching an easier to understand model is beneficial if it has more relevance with the rest of the syllabus. Students learn about all forces at the same time, why not start putting gravity in there too.

    It is the same in the modelling of electron interactions, a simple model of orbital levels is taught in school and can be built upon to include orbital patterns etc further on. In university you would learn to model electrons not as little orbital balls, but as field charges.

    1. Because gravity isn't a force. It either is or it isn't, if it isn't then let's not say it is. I think the reason I object to this in particular, though, is that I think it's the reason curved spacetime and general relativity is so hard to understand (that my brain keeps thinking of gravity as a force, it's really distracting).

      But at the end of the day, I don't really see why we should keep perpetuating outdated scientific views, unless it's clearly an intentional simplification for the purpose of making moves towards understanding the correct model (by which I mean, before someone corrects me, the current best theory).

      I do think we should start introducing more accurate, modern, scientific theories to children though. My concern is that the basic science education we give to children is leaving many adults alienated from modern science, which is a) unfair, and b) making science seem irrelevant and esoteric to the public, which leads to worse science education in the future as parents don't pass an interest in science to their children. Never mind that many primary school teachers firmly believe the things they teach that are not true.

      I could go on about the problems arising from scientific illiteracy in the modern day, but the point is that I think the cause may lie in the way we teach it.

    2. "Because gravity isn't a force. It either is or it isn't, if it isn't then let's not say it is"

      I think it's a bit deeper than that. It is a force when using Newtonian Theory, it isn't when using Einstien's. We do not know what reality "is" we just have diffffernt models. As they say, "the map is not the territory."

      I kind of agree with you in that there should be a better way to teach these things - but you also have to conisder what experiments could you do in a classroom using General relativity, and what maths is needed to go beyond just qualatitive descriptions (for example a rubber sheet and a few heavy balls...)

      PS i just realised this was written months go... oh well ;o)

    3. Hi, thanks for commenting! The thing is, Newtonian Theory was superceded by Einstein's. Of course, Einstein's map still isn't the territory, but it's less wrong than Newtonian.

      Also, don't mistake me for insisting that we teach General Relativity at primary school - as with anything in science (or any other subject) we do things at the appropriate pace. I just think that a lot of adults (including myself) have things like 'gravity is a force' embedded in their brains and I believe this makes, as I said in the comment above, science incomprehensible babble to the general public. Which is a problem.

      By the way - who are you and where did you come from? Just curious :P Anonymity is your prerogative, however.

  2. P.S. The above commenter is Adam, I can't get it to recognise me.

  3. Hey there! I ended up here after your comment on my blog. :)

    Anyway, yes, as I grow older and try to really understand how the world works I keep finding that I have to "unlearn" the stuff they taught me at school and change my "perspective" quite frequently.

    I only figured out a few months ago, after watching this excellent series of video lectures by Leonard Susskind (check it out on youtube it's quite awesome.) that gravity isn't a force in the strictest sense. What we observe as gravity is merely objects following the geodesic in curved spacetime. This concept is incredibly difficult to wrap your mind about.

    Even in relativity beginners learn many "almost correct" models like "space-time is like a rubber sheet which distorts when mass is present" but no analogy is ever completely right.

    In fact, if you want to be completely right the only thing you can say is: "Gravity is only completely described by these set of equations ,(points to einstein equations) and all analogies are only partially correct.

    So perhaps it's necessary to teach these partially correct models at school at least until we can understand the brain twisting details of general relativity.

    Oh and you've got yourself a subscriber. :)

    1. Welcome!

      I'm no longer sure I'm right to object to the phrase 'gravity is a force', in light of the responses I've had, but it just seems to massively undermine one's ability to grok Einstein. Maybe it's just for me (I didn't do any Physics in post-16 education). I worry about the general public's confusion when confronted with science that contradicts their childhood education. I do genuinely think that children could be taught a more advanced scientific curriculum (except that teachers probably don't understand most of it - having not had such an education themselves!).

      Anyway, I'll stick my neck out and say that not only shouldn't children be taught explicitly that gravity is a force (which itself doesn't imply they should be taught relativity), but I also reckon they could be taught the basics of relativity. That's more controversial however, and I'm far from certain about it!