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

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12
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2answers
582 views

Why are so many different types of objects white, yet appear gray when they are wet?

There are many things with different textures that appear white – salt, beer foam, paper, shaving cream, snow, talcum powder, white paint, etc. The most common answer is all of the frequencies must be ...
4
votes
1answer
30 views

Is it possible to use hot cloudy water as a cloud chamber?

This morning I got some warm water from the shower head to a dark plastic basin to wash some sensitive clothes. During the process lots of tiny bubbles got into the water so it had a cloudy ...
23
votes
9answers
6k views

Does car tire pressure change with weight of car load?

Does tire pressure measured by a meter on tire gauge change with load? (I am not interested in pressure produced by car tires onto the road). Car spec usually says "inflate to 220kPa normal load, ...
1
vote
1answer
168 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 ...
3
votes
1answer
116 views

Is it possible that a battery goes flat faster in a cold environment?

I own an old iPod Classic with original lithium-ion polymer battery and I use it primarily while running. Recently I discovered that when a temperature outside is low, usually below 5 C degrees, the ...
1
vote
1answer
34 views

Static electricity experiment

My teacher always asks me to do the experiments on static electricity in winter. I don't know why? What will happen if I conduct the experiment in monsoon?
0
votes
0answers
10 views

Electricity and it's effects [duplicate]

Why do I hear that bizzz sound sometimes from a electrical pole ? I have studied about heat and light effect of current but is there any sound effects too?
1
vote
1answer
83 views

Why do bowlers rub the ball before bowling in a cricket match

Why do bowlers rub the ball before bowling in a cricket match? What is the science behind it? Is it because of friction?
11
votes
1answer
375 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 ...
2
votes
3answers
319 views

Can you punch a hole in an A4 sheet of paper with your hand?

The Heading says it all. But let me explain it a little further. Suppose you hang a sheet of paper (A4 size), from one end leaving the other end free. Now practically it seems impossible to punch a ...
1
vote
1answer
67 views

Everyday phenomena for physicists

I am a physicist by training and like to learn more about everyday phenomena, i.e. how things work. All books on this rather general topic go in the direction of introducing physics, they want to ...
0
votes
1answer
68 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 ...
3
votes
2answers
443 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 ...
13
votes
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 ...
0
votes
1answer
62 views

Can I manually speed up convection?

Let's say, I have half bucket of boiling water and I have added equal amount of freeze cold water to it. I want to have equilibrium temperature reached as quick as possible. Can I speed up the ...
1
vote
1answer
176 views

Why does an aeroplane appear to be moving slowly? [duplicate]

Why does it seem that an aeroplane, even while travelling at 500 kmph at a height of $1.5\text{ km}$ (above sea level), is moving slowly?
6
votes
1answer
94 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 ...
6
votes
1answer
84 views

How can a droplet of liquid float on the surface of the same liquid?

This can happen during the rain, or when pouring water. Sometimes small (1-2 mm) droplets of water float on the surface for some time (a few seconds) before coalescing with the big body of water. A ...
0
votes
3answers
53 views

Work power and energy

When you push your bicycle up on an inclined the potential energy of the bicycle and yourself increases. Where does this energy come from?
2
votes
6answers
893 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 ...
48
votes
5answers
6k views

Why wet is dark?

When something gets wet, it usually appears darker. This can be observed with soil, sand, cloth, paper, concrete, bricks ... What is the reason for this? How does water soaking into the material ...
4
votes
3answers
246 views

(Why) would unmaintained water heater use more electrical energy?

I'm specifically thinking about lime/sedimentation at the bottom of water heater, and calcification of heating elements (and not possible thermal insulation deterioration). It is very often claimed ...
0
votes
1answer
48 views

Is the moment of inertia of the bicycle wheel relevant for keeping bicycle in the upright position? [duplicate]

When we were taught physics at school and the topic was the Inertia and Flywheel, they used as an example that the moment of inertia of the bicycle wheel is the reason why we are able to keep the ...
3
votes
1answer
130 views

How does mud from cycling across a puddle cling onto my back?

While off-roading on a bicycle during a rainy season, it seems inevitable that blotches of mud would stain the back of my shirt at the end of the day. I am not sure the physics behind this. I am ...
3
votes
3answers
219 views

Why does cling film (Saran Wrap) cling better to surfaces which are wet or damp than dry?

The product we know in Canada as Saran Wrap is a clear plastic film (no idea of the chemical formulation, believe it to be polyethelene). Among its uses are to cover a dish or bowl. If the hard ...
74
votes
2answers
4k views

Why does my wooden door disperse light into a rainbow color spectrum?

On a clear morning, light comes through this window (viewed from the inside) It then hits the door on the opposite side (so viewing from the outside the door straight on the other side) There is ...
5
votes
5answers
3k views

Does a full freezer freeze items faster than an empty one?

Let's say we want to freeze a banana. Would it freeze faster if we insert it into an empty freezer, or into one that already contains many frozen bananas?
55
votes
2answers
10k views

Why don't fluorescent lights produce shadows?

I have watched light sources such as incandescent lamps and other lamp sources; they have always made shadows. But a fluorescent lamp doesn't make any shadow. What is the reason behind the ...
1
vote
1answer
55 views

Center of mass of a Soda Can [closed]

I have the following problem and can't seem to get my head around it: The mass of the beverage in a full soda can is $m$. The empty can's height is $H$ and mass $M$. A small hole will be drilled ...
9
votes
5answers
4k views

Does ABS shorten stopping distance of a car?

ABS, from German Antiblockiersystem, is a device put in almost every new automobile. The web has lots of explanations about the system, how it works, but I don't understand how it shortens the way of ...
1
vote
2answers
63 views

How to make the mixed water warmer?

Freezing cold. Nastily I still have to do the laundry by hand. And to keep my hands from being frozen I have to add some hot water to the freezing tap water. Let's just suppose that I have the same ...
0
votes
6answers
6k views

Is it possible to generate electricity using a water tower?

Is it possible to build a water tower that will provide enough pressure to run an electricity generator? A water pump can be used to send water up to the tower. The water pump can be powered by solar ...
6
votes
4answers
962 views

How does “pushing-start” a dead-battery manual car work? [closed]

A few days ago the battery of my car went (almost) dead. As it is a manual car, my father once told me that the way to get it going without jumper cables was to push it or let it roll down a hill, ...
65
votes
12answers
14k views

Why are radiators always placed under windows?

I don't know if anyone else has noticed this but in most buildings and most rooms, radiators are predominantly placed under a window. Now, in my eyes, that is the worst place to put them; hot air ...
0
votes
2answers
57 views

Why do objects seem to move faster (relatively) when they move tangential to the observer?

I've observed this loads of times while travelling, in cars, trains,etc.I can't quite put it in words and therefore I've roughly made a diagram to assist my question. Assume an observer is travelling ...
7
votes
3answers
6k views

What happens to a fully charged battery, when you continue to charge it?

If I leave my cell-phone charging the whole night, it will be fully charged after a while. What happens with the battery and the excess energy I add? Also, I noticed my charger emitting a different ...
2
votes
2answers
81 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
146 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 ...
40
votes
6answers
24k views

Why do power lines buzz?

When near high tension power lines, particularly after a good rain, the lines themselves emit a buzzing noise. A similar noise can be heard coming out of the electric meters attached to my apartment. ...
6
votes
1answer
153 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 ...
3
votes
2answers
139 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 ...
2
votes
2answers
71 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 ...
23
votes
3answers
4k views

Is this really a golden ratio spiral?

In this blog post, I found this picture: Tehre are other similar photos: and Does the water really form golden ratio spiral in such cases? Or is the photo just a provocative example, without ...
7
votes
4answers
18k views

Why is there water coming out of a car’s tail pipe?

I notice yesterday that my neighbor’s car had water coming out of the exhaust pipe in the morning. My first response was since the hot exhaust is hotter than the cold tail pipe, heat is transferred ...
5
votes
2answers
454 views

Why do we hear lesser noise when plastic bags/wrappers are crumpled inside water than when they are crumpled in air?

When plastic bags/wrappers are crumpled in air they make noise. But when crumpled inside water we hear very little noise. Why is it so? Would I hear more noise if I go inside water and crumple the ...
3
votes
1answer
85 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
0answers
77 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.
5
votes
3answers
1k views

Why can't echoes be heard inside a room?

If I go camping and shout anywhere, in the forest or on a cliff, I usually hear the echo of my voice. Why when I shout in my room I do not hear any echoes?
0
votes
1answer
158 views

Circuit breaker Trips during thunderstorm

The circuit breaker at the electrical mains trips at home when there is a thunderstorm outside. Why does this occur?
19
votes
7answers
4k views

The best way in which a man can pull a train

I have chosen this example as a paradoxical limit, but my question really regards the optimization, distribution and outcome of force when you try to pull a weight: how can you optimize your ...