134
votes
Was an Alaskan college student expelled three days after refusing to sell a landmark heating discovery to industry?
The law of conservation of energy says that energy can be neither created nor destroyed.
Normally when we say that some machine, say an electric motor, is "85% efficient", we mean that 85% ...
- 16.8k
88
votes
Was an Alaskan college student expelled three days after refusing to sell a landmark heating discovery to industry?
The footage of "Martin" in the video is actually of Taylor Wilson, a nuclear physicist and scientist who garnered attention in his teens for experimenting with nuclear fusion. The entire ...
- 601
64
votes
Does this "reverse microwave" cool food "without electricity and is 100% sustainable"?
The claim, to no-one's surprise, is false.
Electrocaloric heat-pumping requires energy to be supplied (e.g. by electricity). The alternative would be to break the Second Law of Thermodynamics.
The ...
- 144k
25
votes
Accepted
Does turning the lamp in my classroom off and on use more energy than it being turned on for 30 minutes?
This page at Cambridge University says its a myth. There is a burst of energy when you turn them on, but its equivalent to 2 seconds of run time. Also the light lifetime is not seriously affected by ...
- 16.8k
17
votes
Accepted
Did "hundreds of birds" fall out of the sky in the Netherlands due to a 5G test?
No, while 337 starlings (<5% of the population) and 2 common wood pigeons were found dead in a Netherlands park, this was not due to a 5G test. The birds died 4 months after the only conducted 5G ...
- 14.2k
16
votes
Accepted
Are British plugs safer than all other plugs?
Summary
Death rates for cause electric accidents (per million inhabitants and year) do not differ significantly between Ireland (UK type G) and Germany (Schuko), see below (I did not find similar ...
- 3,546
11
votes
Accepted
Is keyless theft/relay theft a practical threat for vehicles with fob/keyless entry?
Is keyless theft/relay theft a practical threat for vehicles with fob/keyless entry?
Are videos demonstrating it happening practical enough?
https://www.youtube.com/watch?v=bR8RrmEizVg
Police in ...
- 1,810
10
votes
Accepted
Does pulse width modulation (PWM) sensitivity exist in the 362-500Hz frequency range?
tl;dr Don't stick your phone in your face.
It depends on flicker and frequency...
Assessment of the effect on the human body of the flicker of OLED displays of smartphones addresses this, relying on ...
- 21.2k
8
votes
Do fitness trackers make you fatter?
No. Using a tracker does not make you fatter, and that is not what this study claims.
Lets start with the participants:
Among young adults with a BMI between 25 and less than 40
(so no already ...
- 865
5
votes
Accepted
Do cellphones pose any harm to pacemaker users?
Yes, in some cases. The risk seems to depend on the cell phone and pacemaker involved. Apparently there's no conflict in some cases, while there can be in other cases. The American Heart ...
- 4,121
4
votes
Did "hundreds of birds" fall out of the sky in the Netherlands due to a 5G test?
Snopes actually has more details refuting the sequence of events; because tests of 5G use yet unallocated spectrum, they need special regulatory approval.
One such test did occur in an area generally ...
- 63.7k
4
votes
Accepted
Are criminals wandering around with contactless POS sale terminals helping themselves to small amounts from people's RFID credit/debit cards?
Roger Grimes is a computer security professional. In late 2017, he wrote an article for CSO describing his search for confirmed examples of people having the credit cards skimmed by an RFID reader:
I’...
- 144k
4
votes
Accepted
Does fully discharging a Lithium-based battery reduce its lifespan?
For a TLDR version, jump to the last paragraph.
Since AccuBattery links to another paper than the one they actually cited, I felt like double checking if they represented the paper correctly... and ...
- 63.7k
4
votes
Did Marconi steal and patent Jagadeesh Chandra Bose's wireless technology?
Actually The English Wikipedia has a great page about J. C. Bose.
Bose went to London on a lecture tour in 1896 and met Italian inventor Guglielmo Marconi, who had been developing a radio wave ...
- 3,012
3
votes
Does reading off a self-luminous tablet impact the quality of sleep?
Guessing it does not count as science-related: iPads are so bad for your healthy sleep that even Apple offers now a redshifting feature in newer devices. But that is partially because: Evening use of ...
- 44.1k
2
votes
Do 4K displays use more power, because it is hard for the backlight to shine through those super tiny pixels?
Linus is right.
On an LCD screen the light travels through the pixel. The controller on each sub-pixel (see groups of three rgb rectangles in dont_shog_me_bro's answer) determines how that light is ...
- 876
2
votes
Do 4K displays use more power, because it is hard for the backlight to shine through those super tiny pixels?
Yes, this is correct, at least some of the time. Here is an image of an LCD display taken with a microscope:
The black/white parts at the top of each pixel are the hardware for controlling each of ...
- 3,111
1
vote
Did "hundreds of birds" fall out of the sky in the Netherlands due to a 5G test?
There is a short report on the swiss national broadcaster, SRF, about the incident, to be found here, in german: https://www.srf.ch/news/wirtschaft/mobilfunk-geruechte-die-wichtigsten-antworten-in-der-...
- 111
1
vote
Have people died by being shocked through the headphone cord of their cell phone?
It seems there's some evidence that you can be shocked through earphones especially during lightning strikes:
Listening to MP3s in a storm could blow your mind
Some evidence of other shocks non ...
- 170
1
vote
Killed by 9V battery (via multimeter)
If the current has a direct pathway to the heart (e.g., via a cardiac
catheter or other kind of electrode), a much lower current of less
than 1 mA (AC or DC) can cause fibrillation
Source: ...
- 195
1
vote
Do fitness trackers make you fatter?
"The idea of using a fitness tracker is that you should pay more attention to the amount of exercise you get and, therefore, be more likely to get enough. This should support weight loss in people who ...
- 19
1
vote
Can you harvest energy from radio transmissions?
In addition to the other answers, it is the principle by which a crystal radio set (first used by Bose in the 1890's, but not patented until the early 20th centuary) works. This just consists of
an ...
- 171
Only top scored, non community-wiki answers of a minimum length are eligible