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Electricity/music from plants — “Living furniture”! Furniture that produces electricity? It sounds like a fantasy, but it is now true. The technology used is known as biophotovoltaics (BPV), and it utilises the energy produced in photosynthetic processes of algae, mosses, vascular plants and cyanobacteria. A “Moss Table” that works on this principle was demonstrated at an exhibition of new technologies, the Salone Satellite, during the Milan Design Week in Italy, recently.
The table has a cluster of moss plants growing on it. The BPV technology taps into the photosynthetic energy of these plants during the day that is stored in a battery. It can then be used to power various devices such as clocks or to light a bulb during the night. The table was invented by Dr James Moultrie of the Institute of Manufacturing at the University of Cambridge. It is believed that such tables will be able to generate 3 Watts of electricity per square metre. As new low energy consumption lap tops are developed that require only 1 watt to operate (such as XO-1 by Quanta Computer) such tables could power these computers for up to 14 hours.
At the same exhibition the plants were demonstrated to “sing characteristic tunes”, based on their photosynthetic patterns and the corresponding energy variations. This was shown by the Maltese designer Noel Zahra through the “Koishi” concept. Koishi involves the sensing of the photosynthetic variations of each plant and their conversion into musical notes in real time. As each plant has a different photosynthetic profile, it can therefore produce music characteristic for that particular plant, emphasising that plants are living beings, with their own unique life patterns.
Colour changing smart materials Certain fishes, reptiles, amphibians and squids have the remarkable property of changing their colours. They can make the colours of their skin light or dark, or completely change their colour according to their environment. Pulsating bands of colour can also often run across their skins, creating a fascinating picture.
This is achieved by them through contraction of muscles in unison that in turn affect certain special cells (“chromatophores”). These cells contain granules of pigments. When the cells contract, these pigment-containing cells expand, and the colour that they contain becomes the dominant visible colour. In the case of zebra fish a different mechanism is employed. They have similar cells that contain reservoirs of liquid colour. When they contract their muscles, this liquid colour runs across underneath the skin, spreading like coloured ink.
Now scientists at the University of Bristol in UK are designing smart materials that can change colour just like these fishes and reptiles. They have used soft stretchable electrically-activated polymers (“dielectric elastomers”) to achieve the same effects. On application of an electric current, the elastomeric materials can expand, and create affects of changing colours, just like the expansion of the pigment-containing sacs in reptiles and fishes. By controlling the pigments and electrical currents, various shades of fabrics made from these materials can be created.
So in tomorrow’s parties, you may be able to change the colour of your shirt by pressing a button!
Bombardment by meteors/asteroids Each day, many meteoroids enter the Earth’s atmosphere weighing about a hundred tons of material. Most of these weigh just a few grams or less each, and are burnt on entering the earth’s atmosphere (the “falling stars” that are occasionally observed at night). The larger ones can weigh hundreds of tons and can cause craters.
A good example of what happens when a small asteroid hits the Earth is the Barringer Crater near Winslow, Arizona. It was formed about 50,000 years ago by an iron meteor about 30-50 metres in diameter. The crater is 1,200 metres in diameter and 200 metres deep. More recently in 1908 a similar impact occurred in Tunguska, Siberia. The impact was so severe that the sound of the explosion was heard in London half way around the world and all trees within a 50 kilometre radius were flattened.
The real danger to our existence comes from the larger asteroids. There are more than 1,000 asteroids with a diameter of more than one kilometre that cross the orbit of our planet and strike Earth about once in a million years.
One such asteroid (or comet) struck our planet about 65 million years ago, causing a huge crater, 180 kilometres in size in the Yucatan Peninsula in south eastern Mexico. It is considered to be responsible for the extinction of dinosaurs.
