Science projects at minimum cost
|Demonstrate optical diffraction clearly with a red laser pointer and a dead CD. Take a defective or unusable CD (poor quality silver writable CDs are the best) and pull off a section of the metallisation with strong adhesive tape. Shine the laser pointer beam through the clear section and you will clearly see three spots on the wall: A central spot from the straight-through beam with two spots either side which are the first order diffracted beams.|
A physics airtrack works in the same way as an air hockey table. Air blows through hundreds of tiny holes in the table and a puck floats on the cushion of air that is formed between the two. Now the puck can be pushed around and bounce from the sides with very little friction. You can use an extruded aluminium optical rail or square section plastic drainpipe to make an airtrack. Drill 2mm holes every 2cm along each side of the pipe, 2cm from the apex of the track. Join the blowing output of a vacuum cleaner to the pipe and seal the other end. Airtrack cars are made from 0.5mm thick aluminium bent to give a snug fit on the track. Airtrack car have bumpers at each end made of 15mm plastic pipe holders and stretched rubber bands.
A PC projector is a fantastic tool for showing Powerpoint presentations and computer simulations to a whole class but they cost a fortune! A cheaper alternative is to send your PC screen output to a big colour television. Modern PCs and laptops often have a video output that connects straight to the SCART or video-in TV connector. If not, you can use a teleconverter (scan converter) that changes the PC video output into a signal that the TV can display.
PC scanner microscope-magnifier
A PC scanner can be used as a 10x magnification microscope (but not in real time!) Place an object carefully (don’t scratch the glass) on the scanner bed with the scanner set at maximum resolution. Place a light piece of paper over the object to give a good background. Scan! Show the image on screen or print it out.
You can use a clean, white enamelled steel refrigerator door as a magnetic whiteboard – available at low cost from your local recycling centre.