During the session we looked at spectra, waves and optics.
We started by pointing the slit at an incandescent light bulb and saw a complete spectrum.
Looking at a low energy bulb or striplight produced a line spectrum as the flourescent material on the inside of the lamp only produced certain frequencies of light. We then looked at the light from the sky through the window and could just make out the dark lines in the sun's spectrum (called Fraunhofer lines) due to the absorbsion of certain colours by the elements in the suns atmosphere. We decided it would be best to turn off all lights but the one we were observing to avoid confusion when working with a class.
We thought it would be good to provide the students with examples of the spectra of various elements, these can be obtained from gas discharge tubes; pictures of these will be posted here soon.
We built a pinhole camera from a box or can. Practical Physics has practical advice about many physics experiments including the pinhole camera.
We used a camera obscura as a simple way of looking at the performance of convex lenses. We had a some examples of camera obscura kits but particularly liked the do it yourself design using boxes or tubes and a cheap plastic lens. If you need any lenses contact David Swinscoe.
We looked at some experiments using lenses. We held the lens in a retort stand and also used a purpose made lens holder. We used two bright LEDs mounted in a rubber bung as an object, we also used an incandescent bulb as an object. The bulb was a good source for demonstration as the structure of the bulb was easilly visible. The LEDs made a good source for student experiment as the distance between the LEDs can be measured and compared to the distance between the LEDs in the image on the screen, for instruction click here. We used a piece of white card with a piece card glued to the bottom to focus the image onto. We thought that a piece of graph paper or squared paper glued to the front of the screen would make it easier to measure the size of the image
We looked at a demonstartion of building an astronomical telescope on a metre rule using blue tack or using clips designed to hold a lens on a rule. There are details on how to build the telescopes on Practical Physics.
The Instute of Physics provides supports physics teaching in the UK, you should get your school to affiliate.
There is an interactive ray diagram which is useful for teaching optics.
1001 Inventions is a touring exhibition now at the science museum about the Islamic contribution to science between the fall of the classical world and the European Renaissance. The teachers' pack has some great activites with some good historical material and ideas for HSW.