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Questions tagged [physics]

Use this tag for questions about the physical nature of reality and in particular claims that are strictly about the field of physics. Please use specific tags if the question is about other sciences such as chemistry. Also consider to add [electromagnetism] and [radiation] if appropriate.

216
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2answers
32k views

Has man walked on the Moon?

Is there any concrete, solid proof of this space odyssey? Is there a way that I personally have a look a it? Let's say, with a nice telescope ?
103
votes
5answers
6k views

Are personal electronics a risk to commercial aviation?

Are personal electronics (of present or recent past; e.g. cell phones, mp3 players, iPads) a risk to commercial air travel? Is the typical request to "turn off all personal electronic devices" based ...
64
votes
2answers
8k views

Does water have a memory as claimed in homeopathy?

In homeopathic remedies the original substance is often diluted to a point where statistically there should be not a single molecule left of the original substance. The most common explanation by ...
23
votes
7answers
7k views

Are there technologies that provide unlimited free energy?

Many different sources claim to be able to produce "unlimited free energy". For example: UNLIMITED FREE ENERGY IDENTIFIED Company claims to have developed new technology that provides unlimited free ...
13
votes
2answers
6k views

Does earthing reduce oxidative stress and inflammation?

The other day my friend asked what I think about "earthing" claiming that their products provide electrons we used to get from walking barefoot on the earth surface and that they have positive (...
220
votes
4answers
26k views

Does hot water freeze faster than cold water?

Is it true that hot water freezes faster than cold water and if so, what practical applications have there been found for this phenomenon?
13
votes
1answer
6k views

Is the ninth wave the largest?

This famous painting by Ivan Aivazovsky is called The Ninth Wave: Wikipedia tells about the origin of the name: Both English and Russian titles refer to the nautical tradition that waves grow ...
48
votes
3answers
132k views

Is it unsafe to swim during a lightning storm?

I was cautioned by mom that I mustn't go swimming when there is lightning; the theory is that it is more likely for lightning to hit you when you are in the water. Is this fear justified?
22
votes
2answers
2k views

Ultrasound pest control devices

A couple times I've seen advertised on TV and in supermarkets electronic devices that allegedly irritate all sort of insects and rodents, such as mosquitoes, mice, and rats, forcing them away from the ...
25
votes
2answers
3k views

Is a coin toss fair?

I've just seen a referee use a coin toss to decide who will start a match which got me thinking, coins aren't perfectly symmetric. Our euro coins have the value on one side, a country specific image ...
11
votes
3answers
4k views

Is carbon-14 still increasing in the atmosphere?

One argument used to support the idea that the age of the earth is on the order of 10,000 years old (the 'young earth hypothesis') is that radiocarbon dating is confounded by the fact that the levels ...
14
votes
2answers
2k views

Can products that claim to to reduce electromagnetic radiation from mobile phones be substantiated?

There are some products, stickers that you put onto your mobile phone for example, that claim the following Boost your natural defenses in the presence of electromagnetic radiation (EMR) ...
38
votes
1answer
11k views

Did/does the US government keep secret papers by Nikola Tesla?

A popular conspiracy theory holds that Tesla invented a free energy device, but that the powers that be prevented him from publishing it, because it would hurt their investments. Of course, free ...
31
votes
2answers
6k views

Does the Gravitational constant fluctuate?

Rupert Sheldrake recently had a TEDx presentation removed from the TEDx web-site, for making various controversial claims, basically calling all of science into doubt. I am highly skeptical about ...
34
votes
2answers
11k views

Did Manahel Thabet develop a groundbreaking formula to measure distance in space without the use of light?

I stumbled upon the Wikipedia page of Manahel Thabet recently. Here are some extracts from the Wikipedia page. "At the age of 25, she earned her first PhD in Financial Engineering magna cum laude, ...
17
votes
1answer
59k views

Do open windows increase the chance of lightning striking the house?

There's a widespread belief among most of the people I know that all windows should be closed during a storm as having them open is supposed to attract lightning (or, according to some people, can ...
30
votes
1answer
10k views

Did the Quran predict the speed of light?

It appears to be popular to claim that the Qur'an predicted the speed of light before it was scientifically well understood. Although none of the sources state that outright, that is what they imply. ...
20
votes
1answer
14k views

Do we lose 7 pounds when we die?

I often hear people claim that it is a fact that humans lose seven pounds when they die. Some people believe that this is 'proof' of the existence of the 'soul'. Is there any truth to this claim? I ...
14
votes
5answers
7k views

Does the theory of evolution contradict the second law of thermodynamics?

I was reading about the Law of Thermodynamics, and the Second Law of Thermodynamics really interested me because the Law apparently stated that in any isolated system, the entropy of that system will ...
14
votes
3answers
7k views

Man using “water as fuel” for a welding machine? (H₂O → “HHO”)?

I saw a while back a YouTube video that appears to show a news report of a man who patented technology to turn water into "HHO". The video makes some big claims — 161 km (100 mi.) on 0.1 L (4 ...
21
votes
2answers
820 views

Do setback thermostats cause more energy to be used, and does the heating type matter?

It was first brought to my attention by a local HVAC Contracting company, that a programmable/setback thermostat would actually cause my home heating system to use more energy, and hence for me to ...
13
votes
1answer
33k views

Will liver move towards milk?

Someone here in the office reckons that if you put liver and milk in a fridge overnight, the liver somehow 'crawls' towards the milk. I am inclined to think this is rubbish but a casual trawl of the ...
9
votes
2answers
2k views

Does a prototype car that runs on water exist?

In a conversation with a friend recently, she was telling me about a new car that "some Japanese company" had developed, apparently a working prototype that's about to be put into production. It has ...
25
votes
6answers
4k views

Is K-Ar a reliable method for dating rock ages?

Firstly: please try not to bring creation/evolution into this. I will award the correct answer to a response which provides links to evidence and sound explanations. Motivation for the question to ...
5
votes
1answer
1k views

Will the Sun's magnetic activity disrupt electronics on Earth?

I recently came across a claim that the earth's geomagnetism will change and all the electronics devices will be disrupted due to the Sun's magnetic pole change, as described in this video. ...
94
votes
4answers
35k views

Can bullets fired into the air kill a person when they fall?

Lately, I've been watching the Libyan civil war in the media, and both sides in the conflict often celebrate success by firing their AK-47s into the air. Not to say that firing guns into the air is ...
21
votes
1answer
5k views

Is breaking bricks/wood “karate style” an impressive feat?

Related: How do Shaolin monks break spears with their neck? For anyone unacquainted with the fairly impressive looking feat of breaking bricks (or wood) in martial arts, see THIS 1.5min video. I'd ...
42
votes
3answers
13k views

Can mountains on Earth grow higher than 49,000 feet (15,000 m)?

I just saw this picture in Learn Something Every Day and thought of you. Some of the sites I've found reason it with gravity but doesn't explain very well.
28
votes
1answer
4k views

Is NASA working on warp drive?

I am cynical about a report on Gizmodo that NASA is developing Warp Drive. This was trending on Google Plus tonight and gathering a bit of attention. http://gizmodo.com/5942634/nasa-starts-...
53
votes
4answers
12k views

Does water swirl the opposite way on the other hemisphere?

I have heard this one several times but was never given a convincing explanation. Is this a real phenomenon? (Bonus points for a good physical description of the behavior or reasons it couldn't occur....
25
votes
1answer
4k views

Is it possible to obtain current indirectly from power lines?

Can one obtain a sufficient amount of energy for a household's needs by indirect means (induction or otherwise) from nearby high-voltage power lines? Are there any documented cases of such attempts (...
24
votes
3answers
3k views

Does the Torah-encoded age of the universe match science?

Dr. Gerald Schroeder published an article in Aish.com about the age of the Universe and the Jewish bible: So the only data I use as far as Biblical commentary goes is ancient commentary. That ...
22
votes
1answer
18k views

Does paper blunt scissors?

It is widely believed that paper blunts scissors. But it is difficult to imagine why paper should be more harmful than say hair. Is paper really any worse for scissors than hair, or any other object?
19
votes
3answers
1k views

Can a “second Chernobyl” happen at the nuclear reactors damaged by the tsunami in Japan?

In the media, you hear predictions that the events in the damaged nuclear power plants could be "the next Chernobyl", but this sounds like hyperbole to me. Are the events at those nuclear reactors ...
12
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1answer
1k views

Subway magnetic fields and laptop hard drives

I just heard a story of a guy who took the subway to transport his company's off-site data back-ups for storage. When the time came for restore after a disaster, the data was corrupt and erased. ...
10
votes
3answers
1k views

Does the EM drive (electromagnetic drive) work despite the apparent lack of propellant?

In recent headlines, a supposed EM drive, or RF resonant cavity thruster, has been reported to produce thrust despite the apparent lack of any propellant. The drive is purported to work by pushing ...
29
votes
1answer
68k views

Is leaving your AC fan (blower) on 24/7 during summer more efficient than leaving it on auto?

The AC guy that fixed my AC recently said I should turn my AC fan on 24/7 and this would increase the efficiency of my AC system. I looked it up and found this same claim in several places: City Data ...
22
votes
1answer
5k views

Would a human's blood suddenly boil (or eyes/body explode) in a vacuum?

I was once given a question in the popular quiz-show game, You Don't Know Jack, that went something like: You find yourself suddenly ejected into space. Which of these gruesome things happens first? ...
22
votes
1answer
1k views

Does sleeping naked in a sleeping bag keep you warmer?

The most popular question on outdoors.SE is Is it warmer to sleep naked in a sleeping bag? Now, all the answers over there are not properly researched and it was suggested in one of the comments ...
15
votes
1answer
16k views

Do ultrasonic cat repellents work?

Amazon sells roughly 355 different cat repellent products but judging by the consumer ratings, most of them don't actually work -- and even those that do, could be correlation rather than causation. ...
13
votes
4answers
14k views

Is there hard science behind the benefits of home water softeners? [closed]

Does anyone know of any empirical studies or well-tested scientific theories on the benefits (or lack thereof) of using a home water softener? I have a water softener in my house that we installed ...
13
votes
1answer
5k views

Are ion heaters significantly more efficient then normal electric heaters?

An ion heater manufacturer claims their ion heaters are a lot more efficient than common electric heaters: How ion boilers (heaters) STAFOR can reach COP 1,57? In solid conductors only half (...
11
votes
1answer
644 views

Do calcified water heaters use more energy?

It is very often claimed (by both government energy efficiency experts and water-heater sellers/service people) that calcified heating elements in electrical water heaters lead to much higher energy ...
11
votes
5answers
11k views

Are there more 40-moves chess games than atoms in the universe?

I read this tweet recently: "There are more possible games of chess lasting 40 moves than there are atoms in the entire universe. Intriguing to know." I find this highly doubtful. Could ...
24
votes
3answers
3k views

Does the radioactivity on Hiroshima's soil affect radiometric dating?

I heard several times from creationists that now, if scientists would examine the land in Hiroshima, it will tell them it is millions of years old all because of the atom bomb. And because of that ...
22
votes
3answers
5k views

Do tinfoil hats protect against any sort of radiation?

Delusional conspiracy theorists are commonly portrayed as wearing tin-foil hats to protect against mind-control rays from sinister organisations such as [goverments/aliens/NSA/CIA/FBI/liberals/...
17
votes
1answer
13k views

Is it necessary to leave a pool during a thunderstorm?

Most schools and public pools have the policy of closing swimming areas during thunderstorms for fear of electrocution. I was wondering how logical or reasonable this policy is, given that most pools ...
16
votes
3answers
3k views

Can an electronic device reduce scale buildup in waterworks?

I have recently received an ad for a device attaching to my inlet water pipe and a power socket, and claiming to massively reduce the scale build-up. This compact, computerised limescale remover ...
12
votes
1answer
539 views

Can big earthquakes trigger a domino effect?

Can one earthquake trigger another? For instance, the quake in New Zealand, then the one in China and finally the big one in Japan. This does not count aftershocks, but separate earthquakes in ...
8
votes
1answer
1k views

Were two ballistic missiles fired from Spain towards Syria?

The Lebanese news sitem Almanar News cites an anonymous source claiming that two missiles were fired by US forces in Spain towards Syria. They were detected by Russia, it sparked an international ...