Concerns the application of the laws of physics to analyze common situations encountered in everyday life.

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2answers
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Would incense burn at a different rate if oriented differently?

This is motivated by this question in the Puzzling.SE beta about measuring 90 minutes of time using two candles that burn for one hour. (Feel free to read up on that before I spoil the puzzle!) The ...
7
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3answers
488 views

How does a canvas water bag cool water?

I was reading about this water bottle by Botl that behaves like a canvas water bags to keep water cool. I found out that this idea is an old idea and cars would drive with water bags in front as shown ...
56
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7answers
7k views

How does hot water clean better than cold water?

I had a left over coffee cup this morning, and tried to wash it out. I realized I always instinctively use hot water to clean things as it seems to work better. A google search showed other people ...
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3answers
3k views

Is this really a golden ratio spiral?

In this blog post, I found this picture: Does the water really form golden ratio spiral in such cases? Or is the photo just a provocative example, without physics grounds for claims about ...
11
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2answers
1k views

Car headlights glass - why such uneven shape/texture?

Why does the glass on my car's headlights have such a strange shape/texture? Are there physics-based explanations or insights for these features? Wouldn't it be better if it was just transparent and ...
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0answers
12 views

Short clips with transcripts about interesting physical phenomena [on hold]

I want to use of some interesting short clips with their transcripts at physics related to fundamental physics or quantum mechanics or physical phenomena. Can any user guide me?
5
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2answers
294 views

How would an X-ray mirror work?

I was wondering if light can be reflected how can someone reflect X-ray of what material does it need to be made of and is its design completely different to that of our original mirrors? Does this ...
17
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3answers
4k views

How would an X-ray scanner identify a mirror?

A mirror is under normal circumstance used to reflect Electromagnetic radiation also known as photons (light) and in airport security or medical facilities, they use X-rays to detect anomalies inside ...
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1answer
43 views

How Sound of Mobile Vibration travels through wire of Earphones

This may sound dumb, but I have been observing that, If my mobile phone is placed on the wire of my hands free (earphones) and if my mobile vibrates, I could listen the vibration from the ear plugs. I ...
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2answers
284 views

Why do plastic bags make less noise when immersed in water and crushed?

When a plastic bag is crushed in air it makes noise. But when immersed in water and then crushed we hear very little noise. Why is it so? Even if I go inside water, I do not hear the noise the same ...
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2answers
57 views

Sea surfer position displacement

Waves are means by which the energy propagates through a medium (e.g., sea water). This is not associated with a net movement of water in the direction of wave propagation. If this is the case, then ...
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2answers
119 views

Squinting at light sources

I am sure it's just your eyelashes creating a filtering effects, but if you look a a bright(ish) light source such as a lightbulb while squinting, if looks like you are seeing straight light rays ...
3
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3answers
737 views

Is there more energy in the collapse of a cavitation bubble than the energy required to create the bubble in the first place?

The following does not include all scientific details and parameters, only a common summary of "thoughts". What is scientifically wrong with this summary? When you take your beer and tap the top ...
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0answers
11 views

How to survive a lightning strike [migrated]

Is this really a plausible way to survive a lightning strike ?
3
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1answer
189 views

Where is the “event horizon” on a basketball hoop?

I'm watching a lot of basketball this month. A common event is the ball going part way into the hoop and then coming out again. Announcers sometimes claim that the ball was "halfway through" when it ...
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2answers
196 views

How do I figure out the momentum of a water balloon when it reaches the person I am throwing it at?

Recently an experiment was performed in which myself and a partner filled a water balloon and threw it back and forth at each other without breaking it. We gradually increased the distance at which it ...
20
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2answers
691 views

Physics of weird “boing” sound in racquetball courts?

While playing racquetball, I frequently hear a very prominent "boing" sound (or more formally, a chirp). For example, you can hear it in this video when the ball hits the front wall. Does anyone know ...
82
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7answers
5k views

Does Earth really have two high-tide bulges on opposite sides?

The bit that makes sense – tidal forces My physics teacher explained that most tidal effect is caused by the moon rotating around the Earth, and some also by the Sun. They said that in the Earth and ...
14
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4answers
2k views

Why do bubbles make a sound?

I have an understanding of how bubbles work. They encapsulate air (or other fluids) in a membrane caused by surface tension. When they pop, there is often a sound. Sound is a type of energy, kinetic ...
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2answers
107 views

Why does smashing a TV remote load its batteries?

Many times I had the same problem: my TV remote's batteries were too weak for it to operate, but then, when I shook the remote a bit and smashed it on my palm, somehow the remote regained its ability. ...
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2answers
103 views

Why do I hear the telephone ring through grandpa’s hearing aid before the actual phone rings?

I was sitting next to my grandpa (Tato), who wears a hearing aid, on the couch. I’ve noticed that when the landline telephone rings I actually hear the phone ring through his hearing aid (less than ...
2
votes
3answers
215 views

Can random constructive interference with sound waves cause damage?

Any two sound waves have a random chance to constructively interfere with each other at a given spot and this will cause an increase or decrease in pressure. So is it possible that a large number of ...
22
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5answers
2k views

Why isn't the sunset/sunrise rainbow-colored

When the sun is rising/setting, it goes through a phase where the light is bending from the atmosphere. I believe this image will explain much better than I ever could. Now, if light goes through ...
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12answers
8k views

Why is filling a balloon from your mouth much harder initially?

Why is it that when you first fill up a balloon, it's hard to get air through, but after inflating it a bit, it becomes much easier to further inflate the balloon?
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2answers
73 views

Practical (maybe naive) question on boiling water

I put a glass bottle in a big pot, bottleneck up, I fill both pot and bottle with very hot water. The bottle is submerged except a few cm of the bottleneck and filled to the brim so some water ...
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vote
1answer
94 views

Why does a minor vertical vibration cause my coffee to spill?

When I walk my kid sometimes I put a cut of coffee in a cupholder attached to the stroller. When I push the stroller over a brick pavement it seems to vibrate vertically. That is enough for the coffee ...
3
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2answers
81 views

Not-so-hot black shirt

As it is getting warmer here by the minute I was asking myself: Are there materials, that are black (in th visible range) but reflect (most) invisible light? Furthermore, I asked myself what ...
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3answers
496 views

what is this force that is able to surpass an entire planet's force on it?

I have a wet teabag in an empty cup. If I will hold the teabag and touch the wall of cup with it, it will stick to the cup, like there would be glue or some magnetic field, but there's just water. ...
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4answers
50 views

Why does my house seem to warm faster in summer than it cools in winter?

In summers when we switch off the air conditioner, the room seems to instantly get hot again. But in winter, when we switch off the heater the room seems to remain hot for some time. Why this ...
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4answers
292 views

Do objects gain and lose heat at the same rate?

For example, if I take an item out of the refrigerator, set it on the counter for a period of time, allow it to warm up a bit (but not so long that it reaches room temperature and stabilizes), and ...
2
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0answers
57 views

Does a cooler, submerged in water, keep beer colder, longer?

Looking around the web, I see some submerged bucket-like things, without insulation, and some floating coolers, where the actual cooler is not submerged. Given that your water temperature is lower ...
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2answers
65 views

Add weight in front or behind the moving wheel?

Consider a wheel with bearing and axle bar rolling on level ground. If I want to help the wheel continue moving longer(or faster speed), should I add weight by moving the rider body in front or ...
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2answers
88 views

Day/night cycle in Greenland

I have heard that in Greenland there is day for 6 months and night for 6 months. Is this true? If so, how does it happen?
4
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1answer
687 views

The effect of A/C and global warming

I had been thinking about the way an air conditioning system moves heat from one place to another. The unit runs and drops the temp. in the building and raises the temp. outside. Also there is ...
186
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4answers
32k views

Can I compute the mass of a coin based on the sound of its fall?

Other day, I bumped my bookshelf and a coin fell down. This gave me an idea. Is it possible to compute the mass of a coin, based on the sound emitted when it falls? I think that there should be a ...
2
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0answers
59 views

Are the elements of physics different on the upper deck, of a double-decker bus, than those on the lower deck? [closed]

In this question, I hypothesise an event that affects the entire bus; I'm not asking about menace unique to upper floor passengers, such as an overly high upper floor or hanging objects (because this ...
2
votes
3answers
72 views

Golf: spin direction resulting from striking out of the toe

If a golf club strikes the ball out of the centre of the club face with the club path on the target line through impact, and the face square to target, the ball will move towards the target with no ...
36
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5answers
13k views

How effective is speeding?

At a simple level, speeding in a car attempts to minimize the time required to travel a distance by utilizing the basic relationship: $$d=st$$ So for a given distance, time should be inversely ...
2
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1answer
65 views

Are these guard rails truly strong enough?

I'm lay about physics, but I'd like to learn about it behind this question. A friend criticises and claims that the single strip of traffic barriers (as shown below) would fail and is useless. For ...
0
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1answer
86 views

How hot does the upstairs need to be before it will heat the basement through convection?

During the winter we keep the basement door closed so that the cold air from upstairs won't flow into the basement. Then we heat the basement and the upstairs gets heated partially by conduction ...
2
votes
1answer
63 views

Does distance traveled by a vehicle after its engine has been switched off depend on its mass at all?

A vehicle moving with some velocity on a rough horizontal road finally comes to rest after its engine has been turned off. Intuitively, it seems a vehicle with greater mass would stop first because it ...
4
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1answer
90 views

Why is powdered sugar less dense than granulated sugar?

The density of powdered sugar is about 20% lower than that of granulated sugar. There is small composition difference between the two - about 3% cornstarch and 0.5% water in powdered sugar, but that's ...
8
votes
5answers
8k views

Why will crushing a partially empty 2-liter bottle keep the soda more fizzy?

One of the curses of 2-liter bottles is that when carbonated beverages are stored in them for long periods (i.e. days between drinks) at least the last liter ends up being flat. However, if after ...
2
votes
1answer
76 views

Why do i see bright red hand when i place flashlight behind my hand?

When I place a working flashlight behind my hand, I see my hand bright red because of the light. So my question is, why do I only see red light after transmission even if incoming light from the ...
5
votes
2answers
68 views

Will a tall narrow cup keep a cup coffee warmer than a more evenly dimensioned cup?

I noticed a colleague had a tall narrow cup for his coffee, and it got me thinking about whether it would retain heat for longer or not. Assume two cups, both are cylindrical, and both hold the same ...
3
votes
2answers
107 views

Physical Role of Batter in Baseball

Physically, what is the role of a batter in baseball? My question is inspired by How does the speed of an incoming pitch affect the speed of a baseball after it's hit? The answer to that question, ...
78
votes
24answers
8k views

How can you weigh your own head in an accurate way?

I read some methods but they're not accurate. They use the Archimedes principle and they assume uniform body density which of course is far from true. Others are silly like this one: Take a knife ...
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0answers
32 views

Could heavy-lift ships be used as oil tankers to stop oil spills? [closed]

Years ago, I was watching a science programme about some law of physics that prevents liquid from spilling if it was a container underwater. I recall that it was proposed as a safe way to transfer ...
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0answers
41 views

Is it possible to measure ground water level by using coconut? [migrated]

In South India, there are people who claim that they can measure the underground water level by using the coconut. They will hold coconut in their palm and walk on the site. Near the water source the ...
16
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2answers
165 views

Why does sand stick to my shoes?

Well, that's easy: the sand is wet, and my shoes are wet, and hydrogen bonding adheres the wet sand to my wet feet and to my shoes. But then I walk home, and my shoes dry, and the sand on them dries, ...