When vacuum bubbles form in turbulent water, they can collapse violently in a process called cavitation. Scientists reporting in Nature1,2 March 3 showed that the energy of cavitation can heat the plasma in the bubble to 15,000 degrees Kelvin – hotter than the surface of the brightest stars. The resulting flash can sometimes be seen by the naked eye. Science News reports that some believe thermonuclear fusion might take place in plasma within the collapsing bubbles under such high temperatures; imagine that happening in cold flowing water. See also the explanations on Physics Web, Science Now, and Science News. 1Flannigan and Suslick, “Plasma formation and temperature measurement during single-bubble cavitation,” Nature 434, 52 – 55 (03 March 2005); doi:10.1038/nature03361. 2Detlef Lohse, “Sonoluminescence: Cavitation hots up,” Nature 434, 33 – 34 (03 March 2005); doi:10.1038/434033a. This is the kind of amazing scientific fact that can inspire a youngster to take an interest in science. Cavitation can produce such violence in water that it can rip apart steel propellers and erode through solid concrete in dam channels, such as happened at Glen Canyon Dam in 1983 (see videos at Open Video Project). Cavitation may have been one of several effects in a worldwide flood that could have made mincemeat of solid rock with no trouble at all (see CRS article).(Visited 38 times, 1 visits today)FacebookTwitterPinterestSave分享0
1 November 2013South African canoeing development programmes have produced some outstanding successes since 1994, with initiatives like the RMB Change A Life Academy at Nagle Dam outside Pietermaritzburg producing champion paddlers from formerly disadvantaged backgrounds.Now, the Development Academy at Natal Canoe Club (NCC) in Pietermaritzburg is introducing the sport to young children and making huge inroads.With support from the KwaZulu-Natal Department of Sport and Recreation, the programme, which began in April, has so far hosted 1 100 children, and the response has been very encouraging.Sam Phungula heads up the project. He, in turn, answers to Thuthu Manyathi, who oversees the entire development programme. This includes the NCC Development Race, a Dusi Canoe Marathon seeding event, which was recently held for a second time.‘They are loving it’At a recent open day, Phungula spoke about the programme’s successes. “It’s pretty exciting. There are a lot of children who have been taking part and they are loving it,” he said.One of the most notable successes has been the number of girls the project has attracted. “They are the type of people that really want to do this, but they are the ones that are facing the biggest challenges. Since they’re coming from the townships, which are far from here, their parents are concerned about the distances,” Phungula said. The NCC, however, looks after transport for the children.“Most of the girls say they really enjoy the sport a lot, which is good. They’re telling me that in two years’ time there will be many girls participating in the Dusi Canoe Marathon. I am very happy about that,” commented NCC Development Academy member Candy Mavundla, who completed the Dusi Canoe Marathon in a K1 boat for a first time earlier this year.‘I really enjoy that responsibility’“There are many people who are moved to do the sport,” she continued. “Sometimes they even come to my house and say ‘Candy, we also want to come and join your sport’, so I tell them what they need to do. I really enjoy that responsibility.”Participants in the project are taught water safety and how to paddle in guppy boats without paddles before they progress to boats with paddles.A rotational policy splits groups of 40 into two, with one out on the water and the other on land where paddling is discussed and general fitness taken care of. After the sessions the children feast on muffins prepared by Sam Phungula and are provided with transport home.“This programme has given the Development Team such a sense of responsibility and ownership. They are 100 percent responsible for it. It’s very gratifying to see,” said NCC general manager Brett Austen Smith.“I enjoy this a lot, a lot, a lot,” smiled Candy Mavundla. “It has been teaching me about leadership, especially with the coaching, because next year at university I will be doing sports management.”‘Something different about them now’Sam Phungula agreed. “The leadership skills in every one of us have grown a lot. We can talk to people now, we can handle people, even big numbers.“It is very rewarding. Even for the young guys, who are still at school, but are involved in the project, there is something different about them now.”The NCC Development Team has not restricted its involvement with communities to paddling alone. They also took on a community project to assist at an old age home in Imbali. “It has been something different for most of us who have never done something like that,” Phungula said. “We plan to do a community project every year.Reflecting on the visit to the old age home, he added: “We saw something different, something we are not used to seeing, like sick people. It taught us a lot.”Community leadersWatching the children enjoying themselves on the water, Austen Smith pointed out a young boy, not yet 10 years of age. “This chap has been here a few times. He is one of our regulars and you can see how comfortable he is now. He is one of the self-imposed community leaders now. He helps the other guys and tells them what to do. We’ve got a couple of leaders coming out of the communities,” he said.The next step for the NCC development programme will be to unearth some talented paddlers who can go far in the sport. With a club that won four of the six world titles South Africa claimed at the ICF Marathon World Championships in Denmark in September, talented and committed youngsters will find a way to shine.
Private companies step in to help SEA Games hosting In scoring their first straights sets win in the season, the Lady Tamaraws improved to 8-4, needing just one win to make the playoffs for the last Final Four berth.NU had 11 errors, against even by FEU, in the first set, while getting outgunned in the second frame 14-7. It fell out of contention with a 3-9 record.FEATURED STORIESSPORTSPrivate companies step in to help SEA Games hostingSPORTSPalace wants Cayetano’s PHISGOC Foundation probed over corruption chargesSPORTSSingapore latest to raise issue on SEA Games food, logisticsBut the Lady Bulldogs, powered by eight rookies, put up a major scare after Roselyn Doria fired an ace and FEU’s Heather Guino-o dumped a service error for 22-all.But Guino-o redeemed herself in the next play before NU top rookie Princess Robles hit it wide. FEU blockers slammed the door on Princess Robles for the winning point. Philippine Arena Interchange inaugurated Heather Guino-o. Photo by Tristan Tamayo/INQUIRER.netMANILA, Philippines–Far Eastern University imposed its experience on youthful National University to prevail, 25-21, 25-19, 25-22, Wednesday to improve its Final Four chances in the UAAP women’s volleyball at FilOil Flying V Center.The Lady Bulldogs put the Lady Tamaraws on their feet after racing from 17-8 in the third. They tied the frame at 22 but NU fell into a rash of errors to yield the match.ADVERTISEMENT PH underwater hockey team aims to make waves in SEA Games PLAY LIST 02:42PH underwater hockey team aims to make waves in SEA Games01:44Philippines marks anniversary of massacre with calls for justice01:19Fire erupts in Barangay Tatalon in Quezon City01:07Trump talks impeachment while meeting NCAA athletes02:49World-class track facilities installed at NCC for SEA Games02:11Trump awards medals to Jon Voight, Alison Krauss LATEST STORIES Hontiveros presses for security audit of national power grid Cayetano: Senate, Drilon to be blamed for SEA Games mess Panelo: Duterte ‘angry’ with SEA Games hosting hassles SEA Games hosting troubles anger Duterte Don’t miss out on the latest news and information. Wizards guard John Wall unsure if he’ll return next NBA season MOST READ DA eyes importing ‘galunggong’ anew Sports Related Videospowered by AdSparcRead Next View comments Duterte wants probe of SEA Games mess