Rain on a dry topic

While I personally am quite interested in ‘Earth, Sun and Moon’, it is one of my least favourite topics to teach in Primary School science. It is to me a ‘dry topic’. It is one of those topics that there seems to be very little actual science you can do with the children. With forces you measure friction on cars down a ramp; with dissolving you can investigate the effect of heat on dissolving salt in water; with health you can measure pulse rate after exercise.

But what can you measure for Earth, sun and moon? Particularly when it has been raining. And it has rained heavily for the last two Wednesdays. Raining on my dry topic.

The planning document that I was working from started with the sentence: “On a sunny day…” Obviously that wouldn’t wash. But fortunately I had some things to help me:

  • A very large ball
  • A tiny bead
  • Some facts
  • Google Docs
  • Brain Pop

The first thing I did was to get the children to predict the relative sizes of the earth and moon, compared to the very large ball I had found in the PE cupboard.

The children initially predicted the wrong relative sizes for the earth and moon

I was pleased to see that the children predicted things wrongly, because it meant I could teach them something. So I gave them some facts – diameters even:

  • Sun = 1390000km
  • Earth = 12500km
  • Moon = 3500km

I then showed them how I could use a Google spreadsheet to calculate that relative to the very large ball of 60 cm diameter, the Earth would be 0.55 cm (Size of sun ÷ Size of Earth x Size of very large ball) and the moon would be 0.15 cm. It took a few moments for the children to realise that 0.55cm was really very small and was only the size of a bead on a bead string. The moon was a sprinkle that you might put on a cake.

Children hold up the correct relative sizes of Sun, Earth and Moon

The sprinkle was particularly difficult to see, but I think it made the point.

I then used Google Docs to work out the relative distance of the Earth from the Sun. The actual distance is 150 000 000km, which means that the relative distance for a 60cm diameter very large ball is about 65m. We paced that out in the corridor, with a teaching assistant holding the Sun in position and the children coming with me to be the Earth. We had to keep 2 sets of double doors open as we did so.

The Sun is a really long way from the Earth

Back to the classroom and how could we use this knowledge? Presented in a Google Doc was the first answer. The children all began their topic presentations to show others what they were learning.

Suzi's slide on the Earth compared to the Moon

Having seen that the children were beginning to get the relative sizes and distances of these celestial objects I wanted to move on to thinking about how the Earth moves round the sun, how it rotates and all that sort of stuff. No here’s where a shadow and some sunlight can be a helpful starting point. Still no shadows – it was still raining. But mercifully someone has invented Brain Pop.

Embedded within our Google Apps domain, Brain Pop is becoming an increasingly valued addition to our learning platform. It is especially exciting for me, being slightly obsessed with spreadsheets and data, because whenever the children finish a test, their score is automatically updated to a Google Spreadsheet that sits within my document list.

Brain Pop working on the school's Chromebooks

Shortly, the children had watched their first video – an effective explanation of the Earth – and were answering questions on it. Soon they had moved on to the phases of the moon. The one flaw in this – I had forgotten to bring any headphones – this meant that the inimitable sounds of Tim and Moby were soon issuing from 30 Chromebooks.

Mercifully, the rain stopped briefly and we were able to go outside and walk a quarter orbit of the sun (the field was a bit too muddy to walk the rest of the way).

You can just about make out "the Sun" in the distance

James and Maruwa were able to demonstrate the moon orbiting the Earth as the Earth orbits the Sun – earlier they had been delighted when watching Tim and Moby’s explanation of the concept: “It’s just like ours,” they exclaimed.

With new-found Brain Pop enthusiasm, I’m hoping that one or two more Brain Pop quizzes will have been completed on related subjects by this time next week. And I really hope the sun shines next Wednesday afternoon.

One thought on “Rain on a dry topic”

  1. Thanx a million ! Illustration in text books at schools & reference books always showed a massive Sun & a tiny Earth so close that I wondered why the Sun did not fill up sky given the angle it would subtend in our vision. I have been pondering on it, albeit not too seriously till today when i decided to Google distances &sizes of Sun & Earth , a good 38 years after school !
    The kids who study science from you are very fortunate ! Great work !

    Joseph N R / India

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