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

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2
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2answers
380 views

Rainbow reflected on TV screen? (pic attached)

According to wikipedia, A rainbow is an optical and meteorological phenomenon that is caused by reflection, refraction and dispersion of light in water droplets... Given that we require ...
1
vote
1answer
2k views

Can a liquid boil in a closed container?

The title says it all. When one fills a container (with water for example) and closes it so no air can escape from it, then heats the container continuously, can the liquid boil or completely ...
6
votes
1answer
676 views

Why do I hear a deep rumble when I cover my ears?

Probably a trivial thing but a simple google search didn't show anything relevant about it. If I cover both of my ears with my hands, I hear a very deep rumble. If I slowly move my hands away the ...
2
votes
2answers
202 views

Why doesn't a glass french press shatter when boiling water is poured in?

When I was little, I accidentally shattered a glass cooking instrument due to applying far too drastic a temperature change to it. Since then, I've been a bit afraid of doing it again. Of late, I've ...
6
votes
2answers
163 views

Foam patterns on espresso

When just prepared, an espresso has a thin layer of foam, known as crema, on its surface. As I move my drink from the bar to a table, the motion destroys the homogeneity of the layer, but I've noticed ...
3
votes
1answer
230 views

Why are charging times so long for Lithium-ion batteries?

Why do rechargeable batteries (e.g., mobile phone batteries) need sometimes several hours to be fully charged? In other words, what are the physical constraints that don't allow me to charge my iPhone ...
2
votes
1answer
118 views

How do the ice particles interact to produce these magnificent halos?

I googled it and read the Wiki article,but they didn't give any details of its formation. So, I really want to know how these ice halos,that is recently seen near the Arctic, are formed.
1
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0answers
32 views

Ripples of flowing water on a smooth road surface [duplicate]

Yesterday some friends and I were walking in the rain. We noticed that, on a smooth tarmac road surface, the sheet of water flowing down the road was forming ripples as it went. Why was it doing ...
2
votes
1answer
73 views

How can we describe or model the spread of ice during the freezing of the surface of a still lake?

Premise: I live in a place where it is unquestionably wintertime in every aspect of the phrase. I was driving down the street and I drove by a lake. There was a recent and sudden temperature drop ...
-1
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1answer
214 views

How does a faucet work? [closed]

Well I mean how exactly water flows to the sink. How is it pulled through the faucet?
47
votes
3answers
8k views

Can kicking a falling phone save it from shattering?

So I saw this tip but I don't think this is true, it would be that your leg or shoe is more flexible than a hard floor so the momentum change would be slower right?
24
votes
2answers
2k views

When a drop of water falls into water, where do the splashes come from?

When a drop of water falls into a reservoir of water from a high enough altitude, water droplets will splash (image credit): My question: Does the water in those droplets come from the original ...
0
votes
1answer
451 views

Flakes of Ice in Frozen Milk and Orange Juice

When I was a kid, my family used to put our gallon jugs of milk and orange juice into the freezer when we'd go away on vacation so that they would keep longer. As I remember it, if we were gone for a ...
2
votes
1answer
224 views

How can I estimate the cooking time of a roast?

I never remember what worked before, or to write it down someplace. In any case the size and starting temperature will vary. The instructions I learned from refuse to give a time at all, and the ...
0
votes
2answers
674 views

What is the fastest way to heat my car?

During the winter months I often have to drive in a cold car and I want to warm up as fast as possible. What is the best setting to put the air on in order to warm up the entire cabin in the least ...
6
votes
0answers
64 views

Weird phenomenon on aluminum laptop casing [duplicate]

A couple of days ago I observed a phenomenon which I'm not sure I understand correctly. My brother-in-law has recently bought an ASUS gaming laptop in an aluminum casing. When the power supply is ...
4
votes
3answers
835 views

Why does a pitcher with lemon juice have foam, while one with pure water does not?

Whenever I pour water into lemon juice (pouring directly from the tap into the pitcher, not quietly along its edge) I get a foam on top: The same pitcher with water (same water tap, pitcher, time ...
19
votes
1answer
7k views

What happens if you remove the polarization filter from a computer monitor?

Have a look at this youtube video (and some extra footage here). Here I will post a gif showing in short what it is about: It shows that if you remove the polarizing filter from a pc's monitor and ...
0
votes
5answers
208 views

Is there a commonly used unit of measure (other than temperature units) that is not absolute? [closed]

I live in a country where we use Degree-Celsius(°C) to measure the temperature. Sometimes from one day to the other, the temperature rises from 10°C to 20°C and I hear people say, "Wow! Today is twice ...
1
vote
1answer
177 views

Thermodynamics and ice cream

The outdoor temperature is about -30 -40 degree but it does not prevent me to eat ice cream. But I don't know what is the ice cream in thermodynamic point of view. It is not liquid.It is not solid. ...
7
votes
3answers
291 views

Why is concrete dry around cracks?

On a warm and partly cloudy day this summer, I was sitting in my office and suddenly heard rain on the roof. I went outside to shut my car windows. By the time I did that and was walking back into ...
3
votes
0answers
153 views

Why (and how) do foods stick to a pan?

We all (sooner or later) have noticed that foods relatively high in protein (especially those low in fat) are very prone to sticking to a pan, or in general to any non-specially-coated metal surface. ...
0
votes
0answers
20 views

Loud, low-frequency “booming” sound in car [duplicate]

I drive a Scion XD, and I've noticed that whenever I drive at about 40mi/hr or so with just the back windows rolled down, I get a loud "booming" effect at roughly 10Hz. What causes this? I assume it ...
2
votes
1answer
152 views

Why Do Clouds Precipitate Rather than Fall From the Sky?

After spending some time watching clouds, it occurred to me how interesting it is that clouds have more structure than just being homogenous, really humid layers in the sky. I see that a similar ...
0
votes
2answers
164 views

Does a rotating DC motor near a TV affects the signals coming in the TV?

In my TV cable the signals were quite noisy so i cut the wire and hanged both the wire parallel to each other. Then the signals became very clear and everything was going alright. Once I was ...
0
votes
1answer
136 views

Why does the water rise upwards when the bottle fall down with accleretion $>>g$?

When a medium-sized bottle filled with water quarterly falls from a height with acceleration $g$, the water remains calm. But when it falls with acceleration $>>g$, the water abruptly rises up ...
3
votes
2answers
420 views

Why can a person in a noisy room not hear someone outside the room, yet the the outsider can hear the person in the room?

If I'm in a noisy room (radio on, babies splashing in bath, etc.) I struggle to hear someone shouting to me from outside the room. Yet to them, my voice comes through quite clearly. What causes this ...
0
votes
1answer
124 views

Why are we using water pipe instead of air pipe to warm our houses? [closed]

In France, most of the houses are using water pipes. I wonder why this choice was originally done.
2
votes
1answer
571 views

Why does air feel cooler when blown through a small hole and warm through a big one? (for example from a mouth) [duplicate]

I hope the question is clear enough and I'm sure that you can try this thing quite easily yourself. When I blow air from my mouth to my palm through a small opening, I feel cool in my palm, but its ...
26
votes
3answers
4k views

Emptying a bottle faster by swirl

A moment ago, I was emptying bottles filled with water (2 liters) that are on the terrace of my house. As I did so I remembered something I saw on TV a some time ago (I don't remember when or where or ...
14
votes
3answers
713 views

When passed, why does my car 'rock' on the highway when I'm stopped, but not when I'm moving?

I am the blue car in this scenario. If I am stopped on the highway and am passed by a car going fast (about 65 mph), I feel my car rock in the left/right direction. I think I understand why this ...
2
votes
1answer
482 views

How does a bowl of hot water move by itself?

I think everyone should have seen a bowl of hot water moving by itself on a flat surface such as glass(seems like it is moving by itself but maybe there are some external force applied to it when it ...
1
vote
1answer
883 views

Why do the ends of tubelight blink for a considerable time even after the switch is off?

When I switch off the tube-lights , their ends blink for a considerable time. I thought as they were old, there might be some problem. But to my utter surprise, when a new tubelight was switched off, ...
2
votes
1answer
147 views

Why do some objects tend to change their axis of rotation while rotating?

This question struck me a few minutes back, I was at a table with a pear. It was more narrow than round.I proceeded to rotate this pear in one swift movement. It rotated for a few seconds, and ...
7
votes
1answer
160 views

Why does penne pasta go into rigatoni during cooking?

I was boiling penne and rigatoni pasta in the same pot (both are hollow cylindrical pasta of approximately the same length, but rigatoni has a noticeably larger diameter) and almost all of the penne ...
0
votes
3answers
512 views

Why is signal bad in a tunnel?

Consider this: you are driving through a tunnel listening to your AM radio and a GPS, all of the sudden AM radio has nothing but statics and your GPS says "reconnecting - please hold". You say to ...
1
vote
3answers
406 views

Would using a fan cause an air conditioning system to think it's cold?

Recently my office manager said this, after I requested a desk fan: ...using a fan causes a draught, which then leads the air conditioning to believe it’s cooler than it is and it then blows out ...
1
vote
2answers
73 views

How come milk pours smoothly from a bag?

I have seen the commercial about the new beer can where it is vented by puncturing a whole on the can (air behind water). If you just pour normally with normal cans it will get bottle necked and the ...
2
votes
1answer
204 views

Why does my hair get stuck to my cathode-ray TV screen after it is switched off?

My dad's old TV! When I switch it off after watching and get my hands closer, my hands' hair gets attached to the screen. And they stick for sometimes! Now, I know how a cathode ray oscilloscope ...
37
votes
1answer
4k views

Why are dishwasher washed glasses “squeaky clean”?

They seem to have increased friction after going through a dishwasher. The unpleasant (to me) squeaky feel is probably slip-stick friction exciting resonance in the glassware. But why? What has ...
4
votes
2answers
321 views

Why does a cooling car engine crackle?

Why does a cooling car engine crackle? What determines the frequency of the crackles?
22
votes
6answers
9k views

Can a car steer on a frictionless surface?

Do the front tires of a car act like gyroscopes, such that a car could steer on a frictionless surface?
0
votes
1answer
110 views

Why do car wheels seem to roll backwards [duplicate]

For many years i have been wondering about this. When a car stars moving the wheels seem to work normally but as the car speeds up, the wheels seem to roll backwards. Of course that does not happen in ...
22
votes
2answers
515 views

Hourglass on the Moon

Someone asked me this, and I was surprised to find I couldn't answer it: suppose I have an hourglass / egg timer that times two minutes in Earth's gravity. If I used it on the Moon, how long would it ...
1
vote
0answers
45 views

Is there any advantage to using simple syrup over just dissolving sugar and waiting a minute?

When making coffee, I want to sweeten it with sugar. Many coffee shops offer simple syrup which is essentially just a solution of water saturated with sugar. Obviously, this has the advantage that ...
6
votes
3answers
4k views

How do blankets keep you warm?

I heard a famous physicist (was it Feynman?) argue that blankets do not keep you warm by trapping heat but by trapping air next to the body. Is this true?
1
vote
2answers
121 views

What's Optimal About Six Legs According to Physical Laws? [closed]

In many respects the insects can be regarded as the most successful class of animals in evolutionary terms. And one of the most common features of insects is that they (mostly) all have six legs. Not ...
3
votes
3answers
263 views

Why is the required tire pressure inversely proportional to the volume/size of the tire?

I once noticed a tire pressure table on a farm recommended a tire pressure of around 1.0 bar (I don't remember the exact number, but it was definitely below 1.9) for the rear tire of farm tractors. ...
3
votes
5answers
3k views

Why Does Angular Velocity Increase as Radius Decrease?

Suppose a child were to ask you why a tetherball (picture below) seems to speed up as it wraps around the pole. How would you explain this to them? Certainly you wouldn't say something like, "Angular ...
3
votes
8answers
3k views

Dying question: Tractor wheels — large vs small

This question has stumped me for over a month now: Why is it that a tractor has large wheels at the back and small wheels in the front? Current ideas: small wheel in front --> lower center of ...