351

General Science / What have cataclysmic converters done for the environment?

« on: 17/09/2009 21:57:12 »

OK - so I really meant catalytic, but please read on.

Everyone knows catalytic converters are good. They must be, because they convert all those nasty unburned hydrocarbons into pleasant things like, for instance, CO₂.

"Wait just a cotton-pickin-minute Geezer." you might say "Isn't CO₂ one of them dang greenhouse gasses?"

Er, well, actually it is. But it does not produce smog which is really nasty.

"Yes, but I don't happen to live in Los Angeles" you might say, "Smog is your problem. CO₂ is a global problem."


And, did you know that automobile engines will actually consume less fuel and therefore produce less CO₂ if they don't have a catalytic converter?

Perhaps cataclysmic is a better term (he said, quickly retiring to his underground bunker)

352

General Science / How does a Revojet work?

« on: 15/09/2009 04:37:15 »

My big brother had something called a Revojet (around 1955 I think). As I remember, it was really a sort of kite with rotating wings. It was really cool, because anything remotely associated with jets had to be cool in 1955! I remember him flying it on a beach on Orkney. The wind was so strong the string snapped. (Orkney is a dangerous place because you can get hit by airborne sheep.)



Anyway, why does a Revojet "fly"?

353

Just Chat ! / Zucchini - Anyone? Please

« on: 14/09/2009 03:24:09 »

or courgettes if you prefer.



They seem to like it here, far too much. We are running out of recipies. Help! I'm sure they are really pod people. It's dangerous to get too close to them. Have to stay awake. Can't fall asleep. Can't fa............zzzzzzzzzz, snork, zzzzzzzzzzzzz, snork, zzzzzzzzzzzzzzzz, snork, snork, zzzzzzzzzzz

354

Physics, Astronomy & Cosmology / Why do bicycles have such big wheels?

« on: 05/09/2009 16:05:52 »

Well, most bicycles anyway. Is it a macho thing? "Hey, look at the size of my wheels!" or do big wheels serve a useful purpose?

(Lights blue touchpaper and retires.)

355

Just Chat ! / What's wrong with the NSF logo?

« on: 02/09/2009 23:29:25 »

If this forum is all about naked scientists, why is one of the dudes in the logo (I'm assuming it's a dude) wearing a lab coat?

Not sure about the other dude. What's he doing back there anyway? And why are they looking at each other like that?

(Apologies in advance if these questions have already been answered.)

356

Just Chat ! / Are you having a nice day ?

« on: 30/08/2009 16:27:49 »

Well, I was.

Got my first mug a freshly brewed coffee and wandered down to my "office" (it's really the spare bedroom) to log on to NSF to see how my latest incendiary posts were coming along.

I was just putting the mug down on its perch above my mouse and keyboard when there was a little "crick" and a neat little 2 cm long chunk of the handle detached itself from the rest of the handle. This initiated a chain reaction. Coffee dumped onto papers (that should not really have been there) mouse, keyboard, floor. Loud expletive! Panic! Immediate inversion of keyboard and mouse.

I was mopping up the mess when I noticed it wasn't only coffee that was being spilled. I was bleedin' bleeding too. The edges left on the remainder of the handle were as sharp as one of those ceramic kitchen knifes they are always flogging on the telly. Didn't even feel it cut me.

The home can be a very dangerous place.

I think I'll go back to bed now.

357

Just Chat ! / Why do smoke detectors only go mental at night?

« on: 29/08/2009 23:37:15 »

They did it again last night. First at 1:30 am then again at 4:00 am. False alarms of course, and because they are all linked, there's no easy way to tell which one is complaining.

Is it because the dog outgassed, did a spider crawl inside one of them, or do I need to go at them with a vacuum cleaner? Help! I just know they're going to do it again tonight.

358

Physics, Astronomy & Cosmology / Who said The average quantum mechanic is as philosophical as the average mechani

« on: 29/08/2009 06:48:50 »

Who said, or is supposed to have said:

"The average quantum mechanic is as philosophical as the average mechanic."

or words to that effect?



Quantum spanner - increases the probability of connecting with a quantum nut.

359

Physics, Astronomy & Cosmology / How old are photons?

« on: 26/08/2009 20:25:52 »

If I have this right (which I probably don't!) photons travel at the speed of light in a vacuum (well, I suppose they'd have to, seeing as they are light!)

Now, I think that means that, from the photon's perspective (not that it really has a perspective - maybe it does?) it arrives as soon as it leaves. It experiences no time between it's departure and arrival, so, from its perspective it is the same "age" when it arrived as the age it was when it left, in other words, it did not age. - Phew!

However, when light travels through anything other than a vacuum, it slows down (I think). If that is true, then the photon does age when it is not travelling in a vacuum.

Does this ageing effect the photon in any way, or does it have no effect at all?

360

Just Chat ! / Can you identify this series? (trivia)

« on: 26/08/2009 04:36:06 »

Here is a well known series. Can you fill in the blank line?

ST
ND
RD
__

361

Geek Speak / What does this circuit do?

« on: 25/08/2009 21:52:44 »

If the input and the output of the buffer are shorted together, it can't be doing much - right?

362

General Science / Does Thermodynamics make you break out in a cold sweat?

« on: 25/08/2009 19:41:38 »

Well, it always had that effect on me!

Recently I found a calculator in the Internet. It's by Prof "Subi" at San Diego State U. You'll find it at:

www.thermofluids.net

I found it extremely helpful. You can test ideas quite quickly with it.

If you know of any similar calculators, please tack them on to this thread.
(BTW, I have no association with Prof Subi or SDSU)
 

363

Just Chat ! / What sheeps did this?

« on: 25/08/2009 01:25:36 »

Dang sheeps. I thought I heard them sneaking around here last night.

Very funny. Now can I have my pin cushion drive circuit back?

364

General Science / How efficient is my car?

« on: 23/08/2009 05:16:16 »

I get an an average of 30 MPG (US gallons) when my car travels 10,000 miles.

How efficient is my car?

My big honking, conspicuous consumption, Dodge truck only averages 20 MPG in 10,000 miles.

How inefficient is my truck?

365

Physics, Astronomy & Cosmology / Dark Matter - Is gravity really constant?

« on: 14/08/2009 18:51:35 »

Gravitational force results from matter distorting space. I suppose this creates a sort of "gradient" in space that allows objects to "fall" towards each other. Our measurements of this effect are very precise. However, many of these measurements are based on observations in our general locality.

Are there experiments that confirm the gravitational force in interstellar, or intergalactic, space is the same as the force we observe in this locality?

Is it possible that gravitational force is attenuated when there is a lot of distortion of space because of a lot of matter? Could the gravitational effect be greater where space is less distorted by matter?

366

General Science / Why can radio waves pass through a solid wall but light cannot?

« on: 11/08/2009 20:22:45 »

Visible light is composed of photons. I understand that radio transmissions are composed of lower energy photons. A sheet of drywall can block visible light photons, but it has almost no effect on radio frequency photons. Can anyone help me understand why?