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

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Why Does Moving a Cup of Coffee Up and Down whilst carrying it Make it less Likely to Spill?

Sometimes I have a Very Full Mug of Coffee and I am trying to carry it without it spilling. I noticed that if I moved the Mug up and down when carrying it, it seemed to settle the coffee and make it ...
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1answer
842 views

Why is the shadow of a wind turbine a bit slow at first then very quickly, etc. and not equivalent to the wings?

When I stand at a wind turbine and look at the shadow on the ground, the shadow is a bit slow at first then very quickly, etc. Very strange.
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31 views

Can a microwave oven induce an accumulation of static charge in food?

I often "touch test" microwaved food to see if it is heated up enough to my preference. In doing so, I sometimes notice the characteristic tingle of a static discharge between the food and my finger ...
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1answer
35 views

How do we “cancel out” the torque from running?

Running certainly causes a torque on our body, as we are propelled forward via our feet; why doesn't this torque cause our bodies to spin about their center of mass?
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34 views

Why do I hear a squeak in my pipes when my neighbour runs his water? [on hold]

I just installed a new water-heater in my apartment. Now, I hear a distinct squeak from some rooms some times when I or some neighbour run the water. Could not hear this before, and the pipes are all ...
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1answer
44 views

Long, blurry reflections in wet road [duplicate]

When driving on a wet highway at night, any surface emitting or reflecting light will have a reflection right under it that is blurry and seems to stretch to infinity. This is not exactly what I am ...
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0answers
28 views

Twisted earphones-wires [duplicate]

Just the other day I kept aside my earphones after listening to music for a long time, only to find it get twisted, well and good! This happens every time. I feel it is a really strange phenomenon - ...
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1answer
84 views

Real life physics problem: Why is my desktop computer affected by my plasma ball?

Note: this is strictly a physics question, not meant to be an advertisement I was running my desktop with a plasma ball on the side. The desktop has a touch screen enabled. I started to notice that ...
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1answer
40 views

Why does a diver changes his body positions before and after diving?

Before a diver dives in a pool, he changes his body positions several times. When he is about to jump from board he extends his arms and legs but sometime after jumping he closes his body in a ...
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1answer
366 views

Why do flat cords tangle less in my pocket?

We've all experienced this: put a pair of earbuds in your pocket, and when they come out, they're a tangled, knotted mess. However, you can also buy versions with flat, ribbon style cables rather ...
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33 views

3D movie optics mathematics

I get the idea that we use two polarized light sources and a parallax rendered film such that the objects seem to resemble true parallax in our eyes once it passes through the polarized glasses, but ...
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1answer
23 views

How is the efficiency of an electric motor affected? [closed]

Consider that I'm having a motor (AC/DC) and the power switch is on and it's being supplied power and of course the motor is rotating. Now, I continuously start switching off and on the power. For 1 ...
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Why can I turn light red or blue by holding my finger up to it?

This is a difficult phenomenon to explain. Imagine you have an opaque object partially covering a very bright light source, for example, an object held up against the sky. The left hand diagram is ...
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94 views

Viewing computer screen through 3D glasses, why the asymmetry?

I have 3D glasses made up of plastic. First case: When I hold front side of the 3D glasses (by this I mean that side on which light falls) in front of a computer screen, light coming from screen is ...
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1answer
36 views

Why covering our nose with a cloth or nose mask reduces stale smell?

Whenever there is a stale smell in air, we tend to use a cloth(maybe a handkerchief) instantly to get away with it. Why does a cloth or a mask reduce the intensity of a stale smell? Are the "smell" ...
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1answer
59 views

why does the temperature of spray cans always feel cooler than the temperature of the environment? [duplicate]

I know why sprayed gas is cooler due to evaporation thru different pressures, but I can't understand why is the can temperature always lower than environment?
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0answers
37 views

The behaviour that saves more energy/ petrol when driving down-up-hill [closed]

This question is in a way a follow-up of this one: Can a car get better mileage driving over hills?, it is similar to that, is no engineering question and is in no way a homework problem, I'd like you ...
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28 views

AC is more dangerous or DC? [duplicate]

If, though not possible DC also works on specified frequency or follows sine wave form then which one would be more dangerous AC or DC?
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1answer
85 views

Why does paper become uneven when soaked and dried?

Pouring water on a small part of sheet of paper and then drying it makes it uneven, it gets a wave like appearance and seems to have become larger in size. Why?
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2answers
195 views

Why pouring milk from a height makes a chain shape? [duplicate]

I have noticed a chain-like shape when milk is poured from a height into a cup. Actually the chain pattern repeats itself after some distance and again till it reaches the milk in the cup. Any ...
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1answer
33 views

Is, in terms of sound, pouring water in a bottle the analogous of blowing into it?

When we pour some liquid in a closed container, for instance a jar or a bottle, we usually hear two (acoustical) noises: one is the classical turbulent (I guess white) noise, that in my view is ...
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2answers
65 views

What happens when both of Polarizing filter in LCD screen are Horizontal

What would be the result if we replace the vertical polarizing filter in LCD device (screen) with a horizontal filter, what could we see exactly? Would we see the same if we use only one horizontal ...
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2answers
58 views

How can humidity change in a closed room?

I know a closed (not perfectly insulated) space (like a house) can change in temperature if the outside has a different temperature (by diffusion, unless I'm much mistaken). From observation and ...
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1answer
65 views

Why some material is waterproof while breathable?

I am an outdoor lover. Sometimes I am addicted to the jackets made of high-tech materials. There are some materials waterproof while breathable, I wonder how this is possible. They(Liquid water and ...
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3answers
121 views

Why does it seem as if big vehicles “attract” mine when I drive close to them?

When I drive a car at high speed and when I am near to another big car (like a van, or transport vehicle) I feel an attraction to or something push me toward the other big car . What's the physics in ...
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1answer
108 views

What's up with my whipped cream? [closed]

I got a latte with whipped cream this morning, and towards the end of the drink I noticed a peculiar effect. Regardless of how I turned the cup and thereby the coffee, the whipped cream pieces ...
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31 views

Model of scattering in wet things

You know that clothes and some surfaces become darker when wet (covered in an earlier question: why wet is dark?), because of the disordered reflections or of the refractive index of water or ...
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1answer
66 views

The Egg Smashing Tournament

My cousins and I have a annual egg breaking tournament. First, each of us gets a hard boiled egg. Then, in a bracket tournament style, a pair of us face off in an egg breaking round: one person holds ...
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1answer
75 views

How to obtain this equation for skipping stones over water?

I think I have a decent conceptual understanding of the forces at work when stones are skipped over water. My question pertains to the equation found in this [source][1]. Reproduced in Latex this ...
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3answers
185 views

Why most of physics is somehow related to light? [closed]

It seems that for the past 200 years, every physicist is concerned about light. For example : Newton's particle model, Young experiment, Photo-Electrict effect and Einstein's formula, Special ...
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1answer
93 views

Hula-hoop physics

What are the important parameters to consider when trying to keep a hula-hoop in the air by spinning it around the waist? For instance, when shopping for hula-hoops, one can commonly find its ...
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4answers
4k views

Why are stars white?

That is may be a easy question, but I am not a professional. The sun is a star and when I look at the sun is usually yellow. Why stars in the night are white? I suppose is for the distance. What is ...
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2answers
62 views

What is happening when a jenga block tower wobbles?

Imagine I am 3/4's of the way through a Jenga wooden block game. I have a tower and it is starting to wobble. To me it seems there are two possible causes for this: the wood is compressing and ...
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1answer
159 views

During a turn, do the rear wheels necessarily trace out the same arcs as the front wheels?

When a vehicle makes a turn, the two front wheels trace out two arcs as shown in the figure below. The wheel facing towards the inside of the turn has a steering angle that is greater than that of the ...
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40 views

How does water-soluble packaging work?

Recently, I have been using detergent tablets in a water-soluble package for my dishwasher. How does the packaging get dissolved in water?
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6answers
2k views

Does placing a lid on a pot affect the rate of boiling?

On the subject of cooking, someone once told me "If you have too much water in your pot after cooking a dish, just turn up the heat and let it boil without a lid for a few minutes". Now I've thought ...
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0answers
34 views

Cloud chamber with normal ice

Is it possible to build a cloud chamber by using normal ice instead of the usual dry ice? The temperature for dry ice is about 200$K$ while it is about 270$K$ for normal ice.
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1answer
39 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 ...
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1answer
63 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?
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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?
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1answer
183 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?
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1answer
87 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 ...
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1answer
71 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 ...
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1answer
207 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?
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3answers
66 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?
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1answer
107 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 ...
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1answer
148 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 ...
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1answer
83 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 ...
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1answer
89 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 ...
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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 ...