22 February 2007


1) X-files UFO experiment/bike dynamo: a current flowing through a wire creates a magnetic field . The magnetic field produces a force that acts on a neighbouring charge e.g. wires parallel to each other carrying current in the same direction will attract each other.

Magnetic levitation (http://tesladownunder.com) involves lifting a coil off a copper plate. Attaching a coil to an AC circuit allows current to run through the many turns, creating a magnetic field (which is proportional to the number of turns). This produces a force on the copper plate, and the coil levitates i.e. 'anti-gravity'.

Similar experiment: create a dynamo. Moving a magnet in a coil of wire induces a current (Faraday's law) which can then power an LED. Can make something to move a magnet (similar to a bike wheel).

2) Lungs and CO2: linking global warming and how our lungs work. Using the idea of sodium hydroxide trees to reduce CO2. Breating into a solution of sodium hydroxide and bromothymol blue powder causes the liquid to turn from blue to green to yellow as it becomes more acidic. This can be done while at rest and straight after exercise to show the different levels of CO2 we produce.

3) Microbiology: this is very simple and I did it in year 6 - find out who has the dirtiest hands! Everybody presses their finger into a petri dish containing agar, and the bacteria are left to grow for x hours. This can be seen as a milky area in the dish. Kids who had washed their hands before the experiment showed the least amount of bacteria.

4) Design a boat: Thsi is also something I enjoyed doing in Junior school. We had to get into groups of 2 or 3 and build a boat out of basic materials that will carry the most weights in a fixed volume of water.

5) Build a missile: maybe make a rotating wooden disk connected to a DC motor (in a box) to represent the Earth and the children have to make a catapulting device and a sturdy missile to be launched at the right time from the rotating Earth to hit a satellite (if you're Chinese) or an 'asteroid' (if you're Bruce Willis). Lots of physics and a bit of astronomy to play with.

6) Create the best marble run: something easy and fun to do at the end of the day.

20 February 2007


Ideas from the BBC program 'Five Ways to Save the World':

1) Deflect 2% of the sun's rays with a wall of glass 100 000 km in diameter, 3 microns thick! It would consist of many small glass panels. Construction would require 870 000 trips into space. This could be achieved by propelling a rocket from deep inside a mountain (thunderbirds style) using EMF; passing a current through a coil underneath an aluminium disk under the rocket produces a magnetic field which then lifts the disk and the rocket. Rocket accelerates up the mountain via the induced magnetic field.

2) Make clouds more reflective (thus reducing the amount of heat reaching the earth). San Francisco is protected from the sun by the consistent fog. Pump silver iodide into clouds to induce precipitation.

3) Propel sulphur rockets into the stratosphere. Idea derived from volcanic eruptions which spew sulphur high into the atmosphere, leading to a reduction in temperature. At this altitude (20-40 km) SO2 cools the planet, in the lower atmosphere it is a pollutant.

4) Increase the amount of phytoplankton in the oceans by adding nutrients (granules of nitrogen-rich urea). This leads to an increase in CO2 absorption.

5) Create artificial trees that contain sodium hydroxide. Fibres of sodium hydroxide absorb CO2 and convert to sodium carbonate.