Highest scored questions
17,063 questions
92
votes
4
answers
47k
views
Why do color TVs make black and white snow?
If you let a color TV display something from an unplugged display port, it displays snow, right? Randomly varying black or white pixels on the whole screen.
My guess was that the television was ...
- 973
89
votes
10
answers
41k
views
Why do glass windows still exist? (Why haven't they been replaced by plastics?)
Glass is fragile and impractical to transport, install and repair. Even worse, glass kills and hurts people when it breaks. Falling to the streets like guillotines during earthquakes and bomb raids. ...
- 1,091
58
votes
4
answers
37k
views
Why is kVA not the same as kW?
I thought my electric car charging unit uses 6.6 kW of power. However, I found the label and it actually says 6.6 kVA. When I saw this I thought something along the lines of...
Well, $ P=...
- 5,970
54
votes
9
answers
22k
views
Why do cars have mirrors for rear view rather than cameras?
Despite having so much technological advancement, I wonder why cars still uses mirrors (right and left side of the driver) for the rear view. These mirrors can be easily replaced by cameras and ...
- 665
53
votes
13
answers
18k
views
Are toasters really electrified inside of the "slots"?
My mother was born 1950. Me in the mid-1980s. All my life, she's been saying that I must never stick a metal object, such as a knife, into the toaster, because it will electrocute me.
I've always been ...
- 531
51
votes
2
answers
10k
views
How was Volkswagen able to trick the lab pollution test?
The recent Volkswagen pollution test cheating scandal has shocked many people with its widespread extent as well as how it was hidden for so many years.
Last year, the International Council on ...
- 1,178
47
votes
9
answers
7k
views
My customer wants to use my products to do something unsafe. What is my ethical obligation?
We sell products that attach to a motor drive's DC bus. We also formerly sold diode kits that let you hook one product up to multiple drives. We stopped selling those diode kits because they were ...
- 1,685
46
votes
9
answers
8k
views
Is it possible for a bicycle chainwheel to have a fractional number of teeth?
Background
In the world of bicycle motocross, also known as BMX racing, gearing is a hotly-debated topic.
Since the bikes are all single-speed, gear ratio is a fixed number defined as ...
- 563
42
votes
4
answers
68k
views
Transmitting power over long distances what is better AC or DC?
I found this answer to a related question. The part of the answer that's confusing me is:
Transmitting DC power over a long distance is inefficient. Thus AC supply is a far more efficient to ...
- 523
39
votes
10
answers
53k
views
Is it possible to build a perfectly spherical Prince Rupert's drop?
Prince Rupert's Drops are glass objects created by dripping molten glass into cold water. While the outside of the drop quickly cools, the inside remains hot for a longer time. When it eventually ...
- 788
38
votes
6
answers
10k
views
What is the purpose of these “partially filled in” locomotive wheels?
I recently visited a railway museum with a lot of Soviet-era locomotives. The picture below shows the wheels on a locomotive from the 1930s or 1940s. Some of the wheels are thicker on one side (as it ...
- 491
38
votes
2
answers
20k
views
What is the purpose of these diversions in a natural gas line?
The campus where I work has a long covered walkway (~.5 mile) which has several labeled pipes running under the roof (chilled water, fuel oil, air...). All of the pipes run dead straight except for ...
- 483
35
votes
12
answers
48k
views
What are the pros and cons of a traffic circle versus a traffic light intersection?
The debate of traffic circles (also called roundabouts or rotaries) versus traffic light intersections has been in progress for a while. Those in favor of traffic circles say that, among other things, ...
- 611
34
votes
8
answers
9k
views
Is it possible to "pump" a powder?
Is it possible to "pump" a powder the same way liquids can be pumped?
If so, what are the challenges? If not, what are some alternatives?
- 2,384
33
votes
3
answers
12k
views
Why are railroad tank cars bent in the middle?
I recently noticed that the cylindrical shape of a railroad tank car is not completely straight but has a bend in the middle. The entire tank is a bit lower there. What's the reason for this bend?
...
- 433