Monday 2 August 2010

Teaching science at home

I have in the past been accused of being horrible about autonomous educators, a suggestion containing more than a grain of truth. Time now to remember that there are also some prize fatheads in the world of orthodox education. Somebody commented on the piece by Alan Thomas in the Guardian, saying;

'I teach science and point out to parents that homeschooled science isn't a patch on school experiments.'

I won't go deeply into the fact that hardly any interesting or stimulating experiments are now carried out during science lessons in maintained schools, due largely to health and safety fears. Nor will I explore the fact that the practical aspect of chemistry, say, contains only 20% of the marks at IGCSE. One could gain an A without doing a single experiment. I want instead to talk about how richer and more extensive the scientific experiments conducted at home can be.

Take the small matter of teeth, for instance. Students need to know about the different types of mammalian teeth. This is usually done at schools from pictures in a textbook, with the occasional handing round of an animal skull. Hardly likely to grab a child's imagination. In our house, the collecting of animal heads and the examination of their teeth covered a period of almost a year. We began by collecting a few road-kills; a squirrel and hedgehog. After sawing off their heads, we buried them in the compost heap in order to strip the flesh from them. This enabled us also to observe the nitrogen and carbon cycles in action as insects and bacteria went to work on the flesh. We dug them up regularly to watch this in detail. A dead snake gave us the chance to compare mammalian and reptilian dentition. This was followed up with a visit to the dental museum ay the Royal College of Surgeons in London. Then we found a dead fox, dragged it home and hacked off its head with a spade. This caused slight irritation in the household as I forgot to dispose of the headless body and it became a feature of the garden for months. On a trip to the seaside, we were fortunate to find a dead seal on the beach but my wife went mad when she found us dragging this back to the car and we were forced to abandon it. None of these experiments required any equipment nor cost any money.

Even more important than the information about biology, chemistry and physics which was learnt in this way were the wider lessons about the nature of the world. Here is an example. Many children's books about science tell the story of Galileo dropping a large weight and small weight from a high place in order to see what would happen. This is given as a brilliant example of the triumph of practical science over old and false theory. There is a delicious irony about this.

First, here is a question. When Galileo dropped those two weights from a high place, what happened? Did the big heavy weight reach the ground first or did both hit the ground together? Everybody who said that they reached the ground simultaneously loses one mark. Here is the sort of experiment which is never conducted at schools, because everybody knows the answer. However, when my daughter was eleven I was in teaching mode and we were studying physics. I decided to recreate this famous experiment and show my daughter what would happen. I wonder what readers think might have happened when I demonstrated this? In fact when I dropped a weight weighing fourteen pounds and another weighing four ounces from the top of a stepladder, the heavy one reached the ground first. We repeated this with different weights and varying heights. It was no good; the heavy weight always hit the ground first. Every book which describes this experiment by Galileo is quite simply wrong.

I was absolutely shocked by this because I have grown up like everybody else, reading this story and learning how Galileo disproved the old ideas of Aristotle. In the end, having found that literally every mention of this story in books in the local library repeated the same untruthful description of the experiment, we found Galileo's own account of the matter in The Two New Sciences, published in 1638. In this, Galileo actually acknowledges that the heavier weight strikes the ground before the lighter one.

It is impossible to overstate the impact which this episode had upon my young daughter. She learnt that even though every book in a library says the same thing, it is not necessarily true. She would not have made this discovery had I not been pursuing a structured course of instruction in physics. She went on to get an A* for physics, but the most important things she learnt as a result of the lessons had nothing at all to do with science!

This is one small example of the advantages of teaching science at home rather than at school. If the same thing happened at a school, the observation would be ignored and the pupils told to write in their books that the two weights actually did hit the ground together. Incredible as it may seem, I have actually seen this done in a school lesson. The experiment in this case involved covering a leaf from the sun and then testing it for the presence of starch. In theory, there should be no starch present, but every time I have seen this experiment done there has been just as much starch in the leaf kept in darkness as in the control left in the light. The teacher just told the children to write down that after they tested the leaves with iodine, the one from the dark tested negative for starch! The reason for this is that they might later be expected to describe this experiment in an examination and it was important to know what the 'correct' result was. This single incident tells me all I have ever needed to know about the teaching of science in schools and explains why I preferred to teach it myself at home.

15 comments:

  1. Galileo's experiment was repeated using a feather and a hammer on the moon - in vacuo, so no air resistance - by David Scott on the Apollo 15 mission: see
    http://nssdc.gsfc.nasa.gov/planetary/lunar/apollo_15_feather_drop.html
    where you'll find a movie.

    By chance, this was exactly 39 year ago yesterday; frightening how time flies.

    Science teaching wasn't brilliant when I was in school (60s-'70s) although I was lucky enough to have a couple of teachers in physics and chemistry that had done real research. After a few years they left teaching for industry.

    Nowadays it's much worse and the view of science that is conveyed is that it's all about regurgitating "facts" which - as you found - are sometimes erroneous.

    The impact of this very damaging; the children are still inherently bright enough to do sophisticated things - and the best figure it out for themselves anyway - but things have reached the point where even students with very good A-levels have problems with subjects like niversity Physics and get upset when they have to think beyond what they hear in lectures - thinking that is in the very nature of the science they are doing and essential to solving real problems.

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  2. "get upset when they have to think beyond what they hear in lectures - thinking that is in the very nature of the science they are doing and essential to solving real problems."

    Yes, this is as you said because school science is far more about learning a mass of facts and supposed facts; not about investigating the real world. That science could become divorced from the actual world in this way is one of the greatest mysteries of the modern educational system!

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  3. Good grief, who is this Alan Thomas? How ignorant is he? Could you please give a link to the article you mention?

    I sent my son to do a course (at a local community centre) each summer put on by a very frustrated science teacher who told the parents he just wanted to show the kids all the experiments he wasn't allowed to do in his (very good county grammar) school any more. (Yes, health and safety stuff.)

    So, for 5 days each summer, my son got to blow things up and do things that would have scared his mum silly to do at home. I happily paid for this!

    Observation, investigation, testing theories seem to me to be the foundation of science. It was a way of life for us. Although, I wasn't too keen on the dragging corpses home idea. We had friends who did that though and got to see (and touch) the results of their skull burying/boiling and tanning activities.

    Makes me sad that home ed is over...

    Mrs Anon

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  4. "Observation, investigation, testing theories seem to me to be the foundation of science. It was a way of life for us. "

    Yes, it's curious to imagine how one might learn about biology, physics and chemistry without examining the real world! At a local primary school, a teacher started a nature table. You know the kind of things, wasps' nests, acorns, an old skull and so on. The head soon put a stop to it though. Exposing the kids to germs and other unknown organisms. They must now be content with pictures of wasps' nests in books or on the Internet.....

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  5. Oh nature tables! I remember them with such fondness. Always something new to look at, a bird's egg or nest, a discarded snakeskin, seed pod, a rotting tree branch. I coudn't wait to see that was on the table and loved to find things to bring in for it.

    Are you seriously telling me they are a thing of the past now?

    Mrs Anon

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  6. Thank you for this Simon- I have learnt something today, something that I thought I already knew!

    I did have a laugh out loud imagining you (as in the picture I see on your blog) dragging a dead seal along the beach. However I shall take away your sawing off heads etc for skull and teeth away with me- my kids would love it!

    Nature tables gone? I'm sad for that.

    Lisa

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  7. Love the post, especially the image of you both dragging the seal towards the car! I do, of course, have to disagree with this comment,

    "It is impossible to overstate the impact which this episode had upon my young daughter. She learnt that even though every book in a library says the same thing, it is not necessarily true. She would not have made this discovery had I not been pursuing a structured course of instruction in physics."

    Why ever not? This is exactly the kind of thing we did autonomously though I cannot claim to have carried out this particular experiment. It sounds as though your animal experiences were more or less autonomous, or at the very least, not part of a structured course. I do agree though, that structured courses are useful when you want to pull a subject together and fill any gaps in your knowledge. They often reveal links between existing knowledge that you have previously missed too.

    Sadly I don't recall nature tables at our school but my son's room is basically one big nature table so I'm making up for lost time. He has skulls (some bought and others he has cleaned himself), wings (I'm assured they have very little flesh attached so I don't have to worry about rotting!), bats, insects (his own collections along with some embedded in glass), birds nests, eggs (found empty!), antlers, etc, arranged on every flat surface plus more attached to walls!

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  8. I don't know whether nature table have gone from all schools; this is one particular local primary. The head was horrified to see a load of leaf mould, the odd creepy crawly and a few germy old bones laying around the place. As he said, 'Suppose one of the children were to handle these things and then forget to wash their hands?' Doesn't bear thinking about really!

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  9. Apropos of animal heads, when we lived in Tottenham I bought a small shark's head froma fishmonger. The teeth were razor sharp and inevitably my five year old daughter managed to cut herself on them. The wound wouldn't stop bleding and my wife and her were wondering what they would say at the local A&E if we presented with a small child suffering from a shark bite in the middle of London.

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  10. "Why ever not? This is exactly the kind of thing we did autonomously"

    My daughter certainly read all the horrible science books of her own accord; she looked forward eagerly to each new one as it came out. This was of course completely autonomous learning. She asked for them and I provided them. However, like most people, children and adults, if she read the same thing over and over again in many non-fiction books, she assumed it to be true. I was myself absolutely astounded to discover that heavy weights always hit the ground before light ones. I had read about Galileo's experiment so often that I had become brainwashed. I don't think that unless I had been deliberatley setting out to recreate famous scientific experiments, it would ever have occurred to me to climb up a step-ladder and then start dropping rocks and stones from there. Our final experiment entailed dropping large rocks from a disused railway bridge, in order to give us a bit more height. It was very nearly the final experiment in more ways than one because my daughter was on the ground acting as observer as I dropped the rocks. She moved unexpectedly at the psychological moment and the fourteen pound rock missed dashing out her brains by a couple of inches. Imagine explaining that one to social services or the Coroner's Court!

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  11. "Our final experiment entailed dropping large rocks from a disused railway bridge, in order to give us a bit more height."

    Did you manage to test objects with the same volume with different masses? Did they land more closely than objects with both different volume and masses? I think I'm going to have to start experimenting myself!

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  12. "Did you manage to test objects with the same volume with different masses? "

    Yes, by opening up balls and filling them with various things like pieces of lead.

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  13. That's a good idea, did it change the outcomes much compared to occasions where the size varied as well as the weight? Did they fall closer together?

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  14. The difference was minimal. What galileo was actually testing was Aristotles notion that a ten pound weight would fall ten times as fast a one pound weight. this is obviously untrue. In fact the heavier weight reaches the ground only an inch or two behind the heavy one. this is caused by air resistance. The version in books is always simplified until it becomes downright misleading.

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  15. Thanks Simon.

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