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Jonathan Hare's Workshops |
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Parabolic Light Collectors
Parabolic surfaces can be used to concentrate energy for example to focus sunlight to heat things. Using an old World War II spot light mirror we demonstrate how easy it it is to concentrate enough energy to cause combustion. Finally, we show how to make a simple experimental version to safely explore solar heating. See the following link for details of making your own parabolic device.
General Safety Warning: This experiment should always be undertaken with the supervision of a teacher. Never look at the focus or directly at the sun. Caution should always be taken when experimenting with heat and combustion. |
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Bucky Balls
The Buckyball, or C60 molecule was discovered by accident (in the lab) while trying to understand the chemistry between the stars in the Interstellar Medium ISM. The discovery led to the Nobel Prize in chemistry in 1996. Here we look at the structure of C60 and make a molecular model. click on the following link for more information about C60.
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Light Beam
This film should be used with the following article - . Sun light or torch is reflected off a flexible shinny surface fixed to the end of a plastic tube. When one speaks into the tubes sound vibrations pass down the tube and make the surface vibrate. The reflected light is therefore sent off from the surface in a continuously changing set of angles depending on the loudness and frequencies of the voice. The light is said to have become modulated by the sound - we have put our voice on a sunbeam! Getting the sound back (demodulation of the light beam) is also very simple. A solar cell is attached to a speaker amplifier. As the light intensity is changing with the voice so the signal from the solar cell changes. When amplified and sent to a speaker (a device that turns voltage into sound) one hears the original voice again!
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Seawater Battery
This film clip should be used with the following article - seawater battery. When two different metals are placed in a salt solution (an electrolyte) the chemistry produces a voltage. This is called a cell. By wiring up a number of these cells we can make a battery and use it to power electrical circuits.
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Shake A Gen
This film should be used with the following article - shake-a-gen. This is a simple yet effective demonstration of electricity generation. 500 turns of wire are wound onto a 35mm film can and the two ends are attached to an LED light. A strong magnet is placed in the can and the lid fixed back in place. The generator is based on the principle of Faraday induction where a changing magnetic field creates (induces) a voltage in a coil of wire. Shaking the can causes the magnetic field to change with time and so generates electricity in the coil - the LED lights!
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Soldering
This clip is about solder (a low melting point metal mixture) that can be melted using a hand-held soldering iron. The solder also has flux within it to help combat corrosion and produce a good solder joint to the components and circuitry.
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Potato Battery
When two different types of conductors are pushed into a potato chemical reactions take place charging them up - we have a simple electrochemical cell. A potato, zinc screw and carbon rod produce about 1V. We experiment joining a few of these cells up in series and then in parallel circuits to increase the total voltages and currents. With these batteries we power various electrical devices.
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Three Windmills
Converting wind power into electricity seems like an ideal way of helping to solve our energy problems. However, the power generated by a windmill is dependent on the wind speed. If the wind drops to half its speed there is as little as an 1/8th of the power. Here we demonstrate three different types of home made electricity generating windmills and talk about their weaknesses and merits. See the following link for details of making your own windmills. |
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