Thoughts on the Chemistry Bit (part 2) Y3 & 4

I will quickly pass over a bit that caused me to do a double-take in the notes and guidance for materials in Y3. Apparently you should do tests to gain knowledge about the effects of exercise on the human body and measure the effect of exercise on the number of heart beats … hmmm … don’t think we have the right section here. Obviously it’s a typo and we can all do those. But when they start batting on about accuracy and rigour in English, you know what to say!

So on to Y3 section on chemistry/materials. There are two different aspects to the work you have to do on materials. One is about testing and grouping materials according to whether they float or sink or whether they are attracted to a magnet. The other is about rocks (but not soils).

The first part on materials is fine. There are lots of practical suggestions of hands-on activities and I like the suggestion to try out the same material in oil or salty water as well as in water. This will help children to realise that there are two parts to consider when thinking about whether something will float or sink – the solid and the liquid. However, I am less happy about the guidance that is offered to help teachers explain why things float or sink. It’s always a tricky one this. The guidance says to focus children’s attention on the materials something is made of (i.e. density – if it’s more dense than the liquid it is put into it will sink).  But later on the guidance suggests children  find out how boats that float on water can be made out of materials that do not float e.g. steel. So now children have gone from a material (steel) that they have been told will sink because the material is the thing that matters onto a boat made of the same stuff (steel) but will float. That part is decidedly unhelpful and will lead to a number of confused teachers let alone confused children. It really is much more helpful to think of the forces acting on the object – the pull down on the object due to gravity (weight) and the push up from the water. If the force down is bigger than the force up it will sink … if the force down is equal to the force up it will float. But it isn’t straightforward – look at this nice video for a clear explanation with simple diagrams http://www.youtube.com/watch?v=y0SnFCs9z1g. You will see a lot of arrows and talk of pushing but no mention of material. You will also probably recognise that it is a very tricky number to be teaching in Y3. For me floating and sinking is great for reception and Y1 – just putting things in and getting some surprises e.g. a heavy log that floats and a light paper clip that sinks. It is good for helping children accept that the evidence may ask them to re think their ideas from ‘heavy things sink and light things float’ to ‘Some heavy things sink and some heavy things float, some light things sink, some light things float’. But I think the explanation, with its abstract ideas, is best left until secondary school.

The part on magnets is fine but in a somewhat contradictory way the notes and guidance offer no explanation for why some things are attracted to magnets and some are not. So it is Ok for children to see that some materials are attracted or are not attracted to magnets but to get no explanation it but when it comes to floating and sinking children have to be told why. Explanations for some things but not for others in the same section. Weird.

 

And so onto the section on rocks. There is more to do on rocks and the guidance here is fairly helpful with some hands-on suggestions. You also have some big words to introduce – igneous and sedimentary (you don’t have to do metamorphic) – but at Y3 they may quite enjoy learning these words. Anticipate problems however if you tell them that they should now be able to apply their knowledge and think about how a rock/stone near them came into existence. I once tried this by asking a friend who is a geologist to come into school and talk to my class about the rocks they had found to see. Mainly the answer was that he couldn’t be sure what they were. Geology is not simple.

Children also have to look at the formation of fossils which is wonderful if you live near a nice shale beach and can do a fossil-hunting trip to the seaside. Bit tricky for most schools though – so another section to be done passively through chalk and talk or power point.

I am also very sad that the section on soils has gone. Getting children to think about what is beneath their feet is a great way of getting into rocks and soils. For most children soil (aka earth, mud, etc.) is the thing they will come across more than rocks (in their natural state). But what is it made of? How did it get there? Is there soil everywhere beneath our feet/roads/buildings? How far down does it go? Children’s ideas when you ask these questions are fascinating and it is a great area for making them think again and to recognise the links back to the rocks. Soils is one of those overlooked materials but it is vital for the growing of plants and hence food for living things. It is a shame it has gone.

 

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About annegoldsworthy

Primary Science specialist. Going for more independent thinking and less being told what to think. And that goes for teachers as well as children. We need to change that draft curriculum for science. Follow me on twitter @afgoldsworthy
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