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Please include a postal address, daytime telephone number and email address. We reserve the right to edit items for clarity and style. T o answer this question – or ask a new one – email should be scientific enquiries about everyday phenomena, and both questions and answers should be concise. Perhaps you can console yourself by considering the long and complex odyssey of a raindrop. The water then evaporates, leaving behind what it gathered on its journey. Even during a headfirst dive, Robertson reached an. When a raindrop eventually hits a surface, its impact can release the substances it contains. He had expertly controlled his speed by changing his air resistance and therefore his drag coefficient. These coalesce to create clouds and ultimately fall as rain. Water droplets in clouds form when water vapour changes into liquid water around a condensation nucleus, such as a tiny particle of dust or soot, or a flake of salt. I can only assume that, even as far from the sea as we are in Leicester, salty aerosols from the huge waves on the coast had been lifted into the atmosphere and then deposited inland by rain. I rubbed some onto my finger and licked it.
#RAINDROP FALLING ON MY WINDOW WINDOWS#
The same phenomenon happened to me a couple of years ago.Īfter a very big storm with south-westerly gales, our windows and cars were covered in a white residue. It would be interesting to see if the frequency and intensity of desert dust storms increase in a warmer world.ĭust storms in the Sahara can lead to sandy deposits on cars and other surfaces. Saharan dust also delivers vital phosphorus and other fertilisers to the depleted soils of the Amazon rainforest, as well as smaller quantities of these to some other regions. Scientists are experimenting with artificial ocean fertilisation to increase the removal of carbon dioxide from the atmosphere. This helps remove carbon dioxide from the atmosphere, as part of the biological carbon pump. Because the dust particles make the phytoplankton heavier, they then sink to the ocean floor faster. They do the same job as green plants on land by absorbing carbon dioxide from the atmosphere.
Phytoplankton are algae that sit at the bottom of the marine food chain. When it lands in oceans, the dust can provide essential nutrients for the growth of phytoplankton, sometimes creating algal blooms that can be seen from satellites. While it can annoy those who have just cleaned their cars or windows, this dust may help regulate our climate. When the water evaporates, it leaves a fine layer of red dust, which gives the rain its name. But it may be a while before somebody develops an umbrella to charge your mobile phone in the rain.A southerly wind can carry this dust to the UK, and any rainfall washes it out of the air and onto Earth’s surface below. Jager is even thinking of applying his prototype technology to work in air-conditioning cooling towers, where a lot of waterdrops fall, too. The next step is to develop an electronic system for storing the electrical power produced from natural intermittent rainfall. These ultra-low power devices can be entirely powered by energy-scavenging systems if they are operated only several times in a day or in a week," Jager says. "The challenge was to demonstrate that even low-power energy sources can be used to power basic sensor nodes. For example, he found slow-falling raindrops proved best higher speeds lose energy due to splash. Detailed experiments helped him understand the theoretical and practical issues around the design of an energy-scavenging system. Jager's experiments showed that the power produced from raindrops was measured in microwatts - though a single downpour raindrop (5mm in diameter) might generate 12 milliwatts.īut none of this has put Jager off. It converts the raindrop's mechanical energy into electrical energy, with embedded electrodes picking up the electrical charges generated by the raindrop vibrations. Using the demonstrator rig, Jager and his colleagues produced artificial raindrops of different sizes which fell on to a piezoelectric membrane 25 microns thick, made from polyvinylidene difluoride (PVDF) polymer mounted on acrylic glass. One such application is for remote sensors to monitor equipment in the field doing so without a power supply is handy. Progress in microelectronics means that power consumption is down, making it possible to power some devices directly from their environment.
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