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Plant Sciences, Zoology & Evolution / What are the purpose of flies and ants and mosquitoes?

« on: 15/03/2012 09:22:17 »

1. What are the purpose of ants? is it mainly pollination?
2. What are the purpose of flies?
3. What are the purpose of mosquitoes?

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General Science / Can Seeds grow inside the human body

« on: 19/08/2010 11:54:38 »

Is it possible for seeds (any kind) to germinate and actually start to grow inside a human body? I was thinking more in the region of someone putting a seed in his ear, nose, maybe it got underneath your skin somehow or if some how a seed landed up in ones lungg???

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General Science / lightning effect

« on: 15/07/2010 13:11:17 »

If I have a my tv antenna earthed to the ground with let's say 100mm² copper and 10m in the earth. Will my tv see the end of it after a lightning has struck my antenna or not? assume it is connected to the antenna antenna with normal coax cable.

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General Science / What happens when sugar is added to a fuel tank?

« on: 15/07/2010 13:05:15 »

i've heard a rumor that if you somehow get sugar(i assume 5kg or so) in a vehicles fuel tank, the vehicle won't start []. But it one leave the vehicle for about 3 days, it will start again []. Has anybody ever heard this or has this ever happened to anyone?
What effect will it have scientifically? after all, sugar is C12H22O11...

5

Physics, Astronomy & Cosmology / What is the best way to ward off a lightning strike?

« on: 10/06/2009 14:30:07 »

Danie Scholtz  asked the Naked Scientists:
   
Hi Chris,

I want to start by saying I love your show. I listen to your podcasts as much as I can. Although I am far behind on the podcasts, I will catch up one day. I am from South Africa and notice you are on Talk Radio 702 every Friday and listen to all your answers.

I have a question which causes a lot of debates and I am not sure what the answer is. I am 24 years of age and I am working at an electrical engineering firm. So I am fairly familiar with most of the electrical "stuff".

Q: let's say for instance I got a TV antenna on the roof of my house. I stay in town and if I stand on my roof, I can see other houses with antennas higher than mine and some other buildings in the city which is about 4Km away line of sight. So my antenna is not in that big danger of lightning if I can put it that way, there are many other potential around my house for lightning to strike. But as we all know, lightning may strike anywhere.

If I want to minimize my chances of a lightning strike damaging my electronics etc, what would be the way to go?

Scenario 1: with the antenna on my roof, I take a thick copper wire and connect it to my pole holding the antenna and to a strike that is about 2m in the earth. Together with that, I earth my coaxial cable every 3m.i also ensures my TV is correctly grounded.

Ok, so let's say the lightning does strike my antenna... Will my appliances (TV) be damages by the lightning strike?

Scenario 2: with my antenna on the roof, I use a plastic/ rubber pipe and mount my antenna on that. The rubber/plastic pole mount to my brick wall and I ensure that it is isolated from earth as much as possible. I take the coaxial cable from the antenna and put it in an optically isolated device and the output from that device I take to my TV. So bear in mind, I want to isolate the antenna part from earth as much as possible.
So if the lighting does strike my antenna, will it still damage my appliances?

To my understanding, people say you must ground you antenna as good as possible. Wouldn't that "attract" the lightning in a way because it is a good path to ground? Or will the isolated antenna "avoid" the lightning?

If I can give you another example, let's say my house is in the desert and there is nothing else in the open for miles. Considering the 2 scenarios and a storm would be coming over my house, which one will the lightning be likely to strike? Or will there be no significant difference?

Many thanks.

Best regards,

Danie Scholtz

What do you think?