Naked Science Forum

General Discussion & Feedback => Radio Show & Podcast Feedback => Topic started by: chris on 07/05/2003 01:34:02

Title: Flies flying backwards
Post by: chris on 07/05/2003 01:34:02
We received some great questions on the radio show on Monday from the inhabitants of Essex. I've listed a few of them here to tickle your fancy. I thought we could debate the answers amongst ourselves.

1) Roger - "Why don't you get an electric shock from a train"

2) John - "Any link between herbal tea and erosion of tooth enamel?"

3) Anne - "Does aspartame cause bladder cancer ?"

4) ?someone - "Why do stars twinkle, but not planets ?"

5) Mary - "Why is the moon visible in the day time?"

6) Brian - "Can flies really take off backwards ?"

7) ? - "Is it true that fishing bait contains marijuana?"

Be interested in what you lot think about the answers to these !

Chris
Title: Re: Flies flying backwards
Post by: Exodus on 07/05/2003 11:44:19
I'm pretty sure i've heard that flies can take off backwards.... might explain why you can never splat them!

Essentia non sunt multiplicanda praeter necessitatem...
Title: Re: Flies flying backwards
Post by: Dickie on 07/05/2003 15:59:00
Cars build up static as they drive (similar to rubbing a balloon against yourself). You don't get the same charge build-up, as you are insulated from the car (fabric seats). Therefore, by the time the car stops, it is at a different potential to you. It is insulated from ground because of the rubber tyres, so the excess charge can't go anywhere. When you touch the metal of the car, the difference in potential causes a brief current, which can sometimes hurt.

A train has metal wheels, so doesn't build up charge.
Title: Re: Flies flying backwards
Post by: Dickie on 07/05/2003 16:09:18
The light travels a huge number of light years to us with no problems whatsoever, then gains a twinkle in the last few miles as a result of the atmosphere. This is why the best pictures of space come from telescopes high up- either on the top of a mountain, or in orbit.

Planets really ought to suffer the same effect. Maybe because they look bigger the naked eye can't see the twinkle.
Title: Re: Flies flying backwards
Post by: cuso4 on 07/05/2003 17:54:36
We see the moon because it reflects the light from the sun. When moon is visible during daytime that's when it is at position where it reflects sunlight which then enters your eye.

Angel
Title: Re: Flies flying backwards
Post by: cuso4 on 07/05/2003 17:57:50
Aeroplanes also build up static during flights, this is why it needs to be discharged when fueling the aircraft because a spark could easily cause explosion.

Angel
Title: Re: Flies flying backwards
Post by: chris on 07/05/2003 19:45:21
Phew, that's a relief, looks like I answered most of them correctly.

Dickie - don't suns also twinkle a little bit because the light they emit is bent by giant planets in orbit around them (gravitational lensing) ?

Chris
Title: Re: Flies flying backwards
Post by: Dickie on 12/05/2003 13:44:10
Gravitational lensing only really becomes an issue when there's something REALLY HEAVY between the star and us, such as a black hole. I managed to avoid general relativity courses, so I can't really speak as an expert, but I seem to remember hearing about a star that could be seen next to itself because the light travelled both ways around something big and heavy.
Title: Re: Flies flying backwards
Post by: Dickie on 12/05/2003 13:46:18
Same problem with helicopters. If you're being rescued, you should let the ladder touch the ground before grabbing it.
Title: Re: Flies flying backwards
Post by: chris on 12/05/2003 14:40:49
quote:
Originally posted by Dickie

Same problem with helicopters. If you're being rescued, you should let the ladder touch the ground before grabbing it.



So what about when they lower someone down from the helicopter then - presumably they'll get a shock when they hit the ground ?

Chris
Title: Re: Flies flying backwards
Post by: Exodus on 12/05/2003 16:53:47
quote:
Originally posted by chris

quote:
Originally posted by Dickie

Same problem with helicopters. If you're being rescued, you should let the ladder touch the ground before grabbing it.



So what about when they lower someone down from the helicopter then - presumably they'll get a shock when they hit the ground ?

Chris




not if you jump from the ladder rather than step down or vice versa... [;)]

Essentia non sunt multiplicanda praeter necessitatem...
Title: Re: Flies flying backwards
Post by: chris on 12/05/2003 21:03:26
But what about a sea-rescue where they're hooked on ?

Chris
Title: Re: Flies flying backwards
Post by: Exodus on 12/05/2003 21:06:07
erm..... rubber soled boots? stops them from earthing?

Resident Tour Operator - The Naked Scientists
Title: Re: Flies flying backwards
Post by: Exodus on 14/05/2003 12:39:29
quote:
Originally posted by chris

We received some great questions on the radio show on Monday from the inhabitants of Essex. I've listed a few of them here to tickle your fancy. I thought we could debate the answers amongst ourselves.

1) Roger - "Why don't you get an electric shock from a train"

2) John - "Any link between herbal tea and erosion of tooth enamel?"

3) Anne - "Does aspartame cause bladder cancer ?"

4) ?someone - "Why do stars twinkle, but not planets ?"

5) Mary - "Why is the moon visible in the day time?"

6) Brian - "Can flies really take off backwards ?"

7) ? - "Is it true that fishing bait contains marijuana?"

Be interested in what you lot think about the answers to these !

Chris



Did somebody really ask question 7?????! Oh my god!

Is it true?

Resident Tour Operator - The Naked Scientists
Title: Re: Flies flying backwards
Post by: chris on 14/05/2003 22:12:09
mmm no one has properly answered the issue of flies taking off backwards yet either...any suggestions or sites that anyone knows of that deals with this ?
Title: Re: Flies flying backwards
Post by: Exodus on 15/05/2003 02:21:33
i'm sticking with  the idea that flies do take off backwards..... but then i'm drunk. anyone want to try and prove me wrong???

Resident Tour Operator - The Naked Scientists
Title: Re: Flies flying backwards
Post by: nilmot on 16/05/2003 20:24:03
This is a theory,

Flies might be able to take off backwards. They have tiny body weight and their wing spand is wide enough to create an air-resistance, which with this force will be able to push their body backwards.

Not [?] sure [?]

Tom
Title: Re: Flies flying backwards
Post by: Donnah on 17/05/2003 00:59:44
I've seen flies take off backwards (there's that backwards thing again Chris...don't take it personally).  It's much easier to catch them (or squish[}:)] them) when you know that's what they're going to do.
Title: Re: Flies flying backwards
Post by: teeroman on 17/05/2003 04:03:32
Oh Yah....well my grandpa has been trying to teach pigs to fly for 50 years..ever since grandma told him he could have two wives 'WHEN PIGS FLY', poor man pretty near ate himself through a full acre of pig slop one year...he is cute my grandpa...but dumb as a puck....
Title: Re: Flies flying backwards
Post by: Donnah on 17/05/2003 23:01:58
Did you hear the explanation of why Neil Armstrong said "Go for it Mr. Gorski!" when he landed on the moon?
Title: Re: Flies flying backwards
Post by: Ians Daddy on 12/06/2003 22:46:25
As far as the fly taking off backwards...could it be just that? Is it a "take off" as in a jump before it takes flight?

As far as the helicopter and sea rescues... I was in the Navy and we were doing bay drops as training. They told us not to grab the hook until it had touched the water first, due to static electricity. It was a very overcast day and plenty of static. One sailor paniced and grabbed the hook. ZAP! he flopped like a fish. So, the hook and cable would have to ground out first.
Title: Re: Flies flying backwards
Post by: Ians Daddy on 12/06/2003 22:47:49
I guess number 7 would depend on what you were fishing for...hehehe
Title: Re: Flies flying backwards
Post by: Donnah on 13/06/2003 18:19:28
A stone(d) fish?
Fish you cook in a pot?
Reefer fish?
Title: Re: Flies flying backwards
Post by: Ians Daddy on 16/06/2003 07:52:39
He he he....or Smoked salmon? Something with Herb butter?  To go deep T.H.Sea fishing? Puffer fish?
Weedy sea dragon? Skunk clown? Pipefish? Indian smoke angel? High hat? Red eye tetra? Sorry, I got carried away. Being silly. Had to look most of 'em up.
Title: Re: Flies flying backwards
Post by: Donnah on 18/06/2003 01:22:40
Ha ha ha!  Someone else with the same ridiculous sense of humor that I have!
Title: Re: Flies flying backwards
Post by: shug on 26/10/2003 12:48:44
quote:
Originally posted by Ians Daddy

I guess number 7 would depend on what you were fishing for...hehehe



Not really. Hemp seed is extremely nutritous and makes an excellent fishing bait. It also make an excellent human food as it is very high in the 2 essential fatty acids - linoleic and linolenic.

It also makes an excellent bird seed and will usually be picked out fist by budgies etc when fed mixed feed.

There's nothing new in this - in fact birdseed was one of the industries originally excempted in the US when the Marijuana Tax Act was introduced.

Title: Re: Flies flying backwards
Post by: Ians Daddy on 26/10/2003 13:07:47
Welcome to the forum, Shug.

Interesting. I've heard that deer love to eat the plant. Probably alot of animals dig it. I wonder if they get the THC affect. I would've killed a few birds back in my day if I'd caught them eye-balling my good seeds!

I've wondered at times what you would grow if you planted bird seed, but never tried it. Now I have some incentive. All in the name of science...I swear. I've had a few "science projects" confiscated as evidence.[8D] Curiosity may have killed the cat, but it stoned the bird and had Ronnie arrested. [:)]
Title: Re: Flies flying backwards
Post by: shug on 26/10/2003 13:25:47
There's not much chance you'll get it in the US unless you import it on the quiet. Your govt have decided that even trace amounts of THC in hemp makes it too dangerous for your population. (Despite forcing farmers to grow it during WW2). They are trying to prevent any importation of damn near any hemp product - including shampoos, soaps, etc.
http://www.ukcia.org/news/shownewsarticle.php?articleid=6170


Hugh Robertson
Legalise Cannabis Alliance
PO Box 198
Norwich NR3 3WB
Title: Re: Flies flying backwards
Post by: AntiProduct on 28/10/2003 16:17:57
regarding the flies taking off backwards bit....

according to this site (http://www.the-scientist.com/yr2002/jan/research2_020121.html) they can not only take off backwards, but fly sideways and land upside down!

[8)]
Title: Re: Flies flying backwards
Post by: tweener on 29/10/2003 04:14:08
I missed this topic until now.

I've read that recent research is showing that flies actually fly by moving their wing tips in a figure eight motion.  By modulating the motion they are able to generate thrust in any direction, and thus fly in any direction.

As for stars and planets twinkling, stars twinkle due to atmospheric refraction (as stated by Dickie, but planets don't because they are so much closer that they are a small disc and the refractions are mostly averaged out.  They will twinkle under bad viewing conditions(such as just after sunset and viewing over hot pavement).


----
John