1

Just Chat! / Will my septic tank explode if I put dog poop down the toilet?

« on: 10/08/2012 04:14:06 »

Our puppy had an accident at our friend's house. I was going to flush the evidence down the toilet, but he insisted it went in the trash can (dustbin). Does he know something I don't know?

2

Just Chat! / Nice work on the Olympics!

« on: 31/07/2012 06:40:39 »

Despite the remarks of certain couthless US politicians, I thought the Olympic opening ceremony was brilliant, although I did find myself zoning out a bit when they got to the modern bit.

3

Plant Sciences, Zoology & Evolution / Why are the evergreens yellow?

« on: 18/07/2012 23:43:06 »

It's high-summer in the Selkirk mountains. We had an unusually wet June, and the trees seem to be loving it. The tops of the fir trees are actually more yellow than green.

Why is that?

4

Physics, Astronomy & Cosmology / How large can an optical telescope be?

« on: 09/07/2012 02:20:45 »

Phew! You know it's hot when the water coming out of the garden hose burns your hand, but I digress. This is an old hobby-horse of mine. It's been around here before, but I thought it might be worth a re-run during the dogdays.

We know how to create really enormous radio-telescopes by combining the signals from arrays of smaller receivers. Why can't we do the same thing at optical frequencies to synthesize gigantic optical telescopes?

I realize there are a few "details" that need to be worked out because of the rather high frequencies involved, but, other than some technological barriers, is there any fundamental reason why we can't build an optical array of any arbitrary size? (It would not necessarily be terrestrial.)

5

Chemistry / Why is it bad to touch the glass on a light bulb?

« on: 01/07/2012 17:38:47 »

While mucking about with some low voltage lamps, the instructions reminded me not to put my great big greasy fingers on the glass envelope of the light bulbs. I suspect there was an overabundance of caution here as these were 4 watt tungsten filament bulbs, but I know it does do a number on halogen bulbs, presumably because they get so hot.

What is the process that banjaxes the glass? I'm assuming it it's a chemical process, but maybe not?

6

Physiology & Medicine / Why would cause lungs to collapse?

« on: 23/06/2012 03:03:17 »

Our Cairn Terrier managed to snap his retractable leash and go after a porcupine. He was a complete mess and in great pain, so we had to take him to the vet to get him fixed up.

He seemed to be coming along quite well, but yesterday afternoon his breathing became very strange - he seemed be gulping for breath. We took him along to the emergency vet in the evening. Just as well we did because X-rays revealed that one lung had almost completely collapsed, and the other was seriously impaired.

The vet tapped both cavities to remove air, and our Cairn immediately recovered. He seems to be doing OK today, but we'll need to wait and see if the leakage returns.

The emergency vet was really puzzled. We were not aware of any other trauma, nor were there any other signs of trauma on the Cairn. Our regular vet thinks it might be caused by quills continuing to migrate within his body, but he's never seen anything quite like it before.

Any suggestions?

7

Just Chat! / Is my keyboard allegric to Bud?

« on: 12/06/2012 07:24:21 »

Oh calamity!

I managed to knock over a can of the fine Budgeezer ale and, of course, a significant amount of the spillage ended up in my keyboard. (There must be a law that dictates why that always happens - but I digress.)

However, as I know about these computer thingys, I was not overly concerned. I dismantled the keyboard and gave the mechanical bit and the rubber panel beneath it a good decontamination (I washed them in warm water with a touch of detergent). Prest-chango! Keyboard thingy works fine and also looks like new cos all the crud has been removed.

There's only one problem. My computer used to come out of sleep mode as soon as I hit the any key, but now it don't! It only responds when I click the mouse. Weird!

8

Chemistry / How can I remove the cloudy deposits on the insides of my sealed pane windows?

« on: 29/05/2012 18:56:16 »

What can I use to remove the cloudy deposit on the inside of my "sealed pane" windows when the seal has failed and moisture gets in? I will drill two holes at opposite corners of the outer pane so that I can flush and vent the space.

I was thinking a mixture of vinegar and distilled water, possibly followed by an alcohol flush to dry it out. Would that work?

9

Technology / Do you need a few more pixels for your camera?

« on: 19/05/2012 17:17:30 »

How about this -

http://www.vivalageek.com/2012/05/18/huge-camera-sensor-can-photograph-the-sun-and-stars-in-daylight/

(The bit that got my attention was viewing stars in daylight!)

10

General Science / Do we scale models properly?

« on: 12/05/2012 07:01:34 »

OK - so I still play with toy trains. Get over it!

Here's the thing:

In the US, and most of Europe, a common model scale is HO, and the scale ratio from the real thing is 1:87. Due to a lot of history, the UK (mostly) landed on OO, which has a ratio of 1:76

Now, 1:76 against 1:87 does not seem like that much of a difference, but when you compare the same original modeled in both scales side by side, the difference seems to be far greater.

Is our perception of scale based on volume? If so, should we cube the difference in ratios?

11

Geek Speak / Mission Impossible

« on: 07/05/2012 02:06:41 »

Mrs G is visiting her parents in the UK and having a bit of trouble with her mum's computer. She writes:

"every time I want to get on the internet I have to switch off power to the computer and reboot the modem"

Any suggestions?

I'm afraid I have no idea which Windows version it's running, and I don't know anything about the modem and the ISP! (Hence the title of the thread.)

12

Physics, Astronomy & Cosmology / Are frames of reference even more misunderstood than centripetal force?

« on: 15/04/2012 06:54:36 »

Every time I get into a debate about the convenient, yet non-existent, centrifugal force, somebody always tries the old, "ah, but in a rotating frame of reference" argument.
 
I'm probably just too old-fashioned, but I was under the impression that you can't flip-flop between different frames whenever the going gets slightly tough. If you apply the Earth frame to a model, you have to describe EVERYTHING with respect to that frame. You can't suddenly claim that the frame is rotating because, by definition, if there is any rotation, it is because everything is rotating around that frame. (I think that has been tried already, but it didn't get too far.)
 
Seems to me that "frames" are being used as a sort of scientific "Three Card Monte" by people who really have no idea what they are on about, or am I just being too old-fashioned?
 
 

13

General Science / Will iron slow the rot?

« on: 10/04/2012 16:54:41 »

A geezer asks:
 
If I stick a tray of iron filings in my fridge, will it reduce the rot rate of my veggies?

14

General Science / What is the weight of a bicycle?

« on: 19/03/2012 06:46:55 »

My bicycle weighs exactly 16kg, but that's when I'm not pedaling it. What does it weigh when I'm zipping along on it at 30km/hour?

15

Technology / Why not super-tubes?

« on: 07/03/2012 23:34:50 »

Why don't we use super-tubes instead of aircraft? A super-tube is a "tunnel" (although it need not be subterranean) that has most of the air removed from it. Train-like vehicles traveling in the tubes would be accelerated to, say, 1500mph (possibly quite a bit more), and probably coast most of the way to their destination. Of course, I don't think it would make much sense for distances of less than 1000 miles.

The capital cost of something like this would be high, but the long term energy saving and reduction in air pollution would be considerable, not to mention that it would save a lot of time. As most of the friction is eliminated, the only energy consumed is the energy that goes into accelerating the vehicle and its payload, and a large percentage of that could be recovered if the system used regenerative braking.

Has anyone heard of any studies of something along these lines?

16

Physics, Astronomy & Cosmology / Is the coefficient of sliding friction constant, or not?

« on: 04/03/2012 20:13:16 »

I was always taught that the coefficient of sliding friction remains constant regardless of speed, or at least until so much heat is generated that surfaces start to melt and act as a lubricant.
 
I've found data on gears (worm gears more specifically) that indicate the coefficient of sliding friction (bronze on hard steel) actually reduces with greater sliding speeds. Presumably this has been confirmed by lots of measurements over a large timespan.
 
Any suggestions as to why this might be? Is it a fluid dynamic effect associated with lubricant?

17

Chemistry / Why is my mouse bleeding?

« on: 27/02/2012 23:58:21 »

Aaaarggg!

My computer mouse developed a nasty blister on its side, right where I park my thumb. When I squeeze the blister, some clearish oily looking liquid oozes out.

Is this mouse blood? Is it dangerous?

18

Technology / Why don't field effect transistors have four terminals?

« on: 24/02/2012 04:51:45 »

To put it another way, why can't the control field be made to "float" with respect to the channel?

19

Just Chat! / The "Speilberg Look"

« on: 22/02/2012 07:36:06 »

For a while I was wondering why this guy was so cheap that he wouldn't buy a decent razor. Heck, he could buy an entire razor company if he wanted to. I think I have finally grokked it. He really does not care too much what people might think of his appearance - he's going for comfort!

When I have a close shave it does a terrible number on my skin, but when I grow a serious beard, it turns back and starts to attack me. For me, the most comfortable state is a state of stubble.

Today I purchased (at great expense I'll have you know) a "stubble look" electric shaving machine (for reasons that I do not understand, Mrs G seemed to find this highly amusing).

I will provide periodic reports on the efficacy of this device.

20

Physiology & Medicine / Why do we dump and run?

« on: 22/02/2012 05:01:47 »

I have heard from many reliable sources, among them Sheepy, who happens to be an authority on this subject, that humans under extreme duress (as, for example, when a bear charges) will actually doo an involuntary dumperoonie.

What is the evolutionary advantage of so dooing? Does it have to do with weight, or is there an olfactory connection?