## The Physical World: Light and Sound

There is so much to cover in this term’s classes. I am a former physical chemist and I probably could spend the whole year going over physics as I enjoy every part of this subject.

We started off with waves, specifically sound and light.

In the first class I told the children we were thinking about these two questions:

What are waves?

What is sound?

I asked them all to say what was the first sound they heard as they woke up in the morning.

We felt our necks while singing, and looked in books about the human body, to find out how human voices produce sound and how it gets to our ears.

In one group we brainstormed different musical instruments and talked about what part of the instrument was vibrating, and classified them into the different groups of instruments (wind, percussion or strings). This was too much discussion and not enough hands-on activity so I dropped it from the class for the next group.

We went around the area with strings hanging from coat hangers to do this ‘secret sounds’ experiment from Science World British Columbia.

From these activities we started to talk about sound as a vibration.

I introduced the term ‘longitudinal wave’ and the children used a slinky to model longitudinal waves and transverse waves.

The children modelled these kinds of waves themselves too, standing in a line.

In the second class we converted plastic milk bottles into vortex cannons, using rubber bands, plastic bags from the supermarket and plenty of duct tape. This was a very fiddly activity and the children needed loads of help and supervision. I would do this differently next time!

For a slightly more advanced version of the vortex cannon see these instructions from G A Brown design, who did this activity in a scout group.

Or for a far larger one, see this video:

The children arranged cards with different colours on, to show the order of colours in the visible part of the spectrum. We talked about how different animals can see ultra-violet and infra-red, so we added them on to the electromagnetic spectrum. We added other electromagnetic waves and some cards to show the wavelengths of all of these waves. I think this went over the children’s heads! Another class I will do some more activities to reinforce ideas of scale and the units we use at different scale.

I also talked about the speed of electromagnetic waves, frequency and wavelength but I think this would need more reinforcement too.

I used UV sensitive tattoos and UV-reactive face paint in one group. The other group has those pleasures to come. I also want to cover the dangers of UV light, and each child has the opportunity to do a presentation about light and how we use our scientific knowledge to solve problems to do with light.

### One thought on “The Physical World: Light and Sound”

1. julija 20 February, 2016 / 15:11

I will show the kids these videos as a follow up – really great!