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

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2answers
231 views

What make us fall when we move on ice? [duplicate]

This is a common phenomenon and most of the people have encountered this while moving on ice:falling down! Why does this occur? According to me, it is due to lack of static friction. But why will it ...
3
votes
2answers
732 views

Why can't we reach the ends of rainbow?

Rainbows are spectacular things. But I imagine why we can't reach to the ends of rainbows. Do rainbows have no ends ? If so, why can't we reach at them? If you go closer,they will go further. Why?
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1answer
99 views

Magnetic field of magnetic screwdriver?

I wanted to know what is the typical strength of the magnetic field generated by the tip of a magnetic screwdriver, but couldn't find it anywhere on the manufacturers' webpages. So I was wondering, ...
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2answers
316 views

Why do corn flakes clump together in milk when stirred? [duplicate]

The Cheerios Effect is the name the scientific community has given to this phenomenon. When cornflakes or oats are mixed with milk and stirred, they tend to clump together. Why does this happen? Can ...
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3answers
5k views

Why do the big nuts always remain at top? The Brazil-nut Effect

Most of the time when I mixed different nuts in a bowl, I observed that the big Brazil nuts were always on top while the small peanuts settled near the base. No matter how you take it, if the big nuts ...
22
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2answers
3k views

Why does a dish cloth absorb liquid better when it is damp?

Take a really dry dish cloth and try to wipe up some liquid you spilled on the kitchen counter. I will take up only so much of the liquid. Then try it with a damp cloth (or a wring out a wet one). It ...
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3answers
7k views

Benefits of rear spoiler in cars

What would be the benefits of rear spoilers in cars, like this one:
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1answer
47 views

How big are soluted salts in drinking water?

I have just seen the TED talk Michael Pritchard: How to make filthy water drinkable where a device called LifeSaver bottle that filters particles that are bigger than 15nm out of water. I have heard ...
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2answers
2k views

Glass tends to be cold?

In winter, our glass window serves as a separator of coldness outside and warmth inside our room. We know that the window feels cold when we touch it. Since the air temperature is different in ...
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0answers
498 views

Definition of spatial and temporal coherence in QM?

It is often said that lasers are spatially and temporally coherent. Is there a simple definition of spatial and temporal coherence in the language of quantum mechanics? More specifically, can these be ...
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3answers
22k views

Why do we use kilograms instead of newtons to measure weight in everyday life?

What was the reason to use kilograms to measure weight (e.g. body weight, market vegetables etc.) instead of using newtons?
14
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2answers
2k views

Why is cooling much harder than heating?

I'm trying to invent a distillation apparatus that runs solely on electricity. Suddenly, I realized that cooling things is really hard, while heating them up is so easy. Actually, it seems that there ...
4
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1answer
597 views

Why do bubble wands have ridges?

The bubble wands supplied with children's bubble mixtures seem to fairly universally have a set of ridges around the hole used to create bubbles - for example, see the circle in the upper right of ...
79
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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
1answer
922 views

Why is wet paper transparent? [duplicate]

When paper get wet, it becomes transparent. How does this happen? Is it because of refraction, or bcause water extends the space between molecules that consist of the paper? I have no clue.
6
votes
1answer
236 views

Steam above meal

When I fry something on the pan and the fire is big and intensive (the flame over the pan), there is no stean above the pan or just a little. But when I turn off the fire, suddenly the steam appears, ...
2
votes
1answer
177 views

Cold welding of a metallic surface

I have heard of cold welding, it's said that it's only possible if the surface is very clean. Can cold welding be accomplished by shearing a metal object and then immediately touching the newly ...
5
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2answers
2k views

How does train back draft work

Quoting platforms and stations : Fast trains can create a vacuum called a ‘back draft’ that can blow you over or suck you under a train. How does that work ? I thought that the volume of air ...
17
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3answers
2k views

Why is the sky dark at night? [duplicate]

The question is the well-known Olbers' paradox: If there are so many/infinite stars, in every direction, why is it dark at night? Where goes all the light we don't see? Discussing with a friend ...
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1answer
52 views

Modeling wall's behaviour

Sorry if the quesiton is inconvenient, but I judged the physics forum would be the best place to go. My house is divided in two parts by a wall, and there's some tree pushing it, so the wall is about ...
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1answer
124 views

Will a tug-of-war battle damage my climbing rope

I plan to organize a big tug-of-war with a climbing rope (70m long) with 50-60 adults. I know the climbing rope is elastic. The rope resistance is 9 kN when a chock occurs. Will the rope breaks or ...
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2answers
94 views

Which dumplings will be more salty?

There are two identical pots filled with different amounts of water (one has more water, the other one has less). The same amount of salt has been poured to each pot. The same amount of dumplings has ...
3
votes
2answers
438 views

How can you accurately determine your own mass?

I'm trying to figure out whether it is possible for an individual to accurately determine his/her own mass, to within 100g, using equipment that is readily accessible or can be purchased at a ...
3
votes
1answer
66 views

What is the best angle to see water

Sometimes when I clean my house, I miss some of the water since it seems invisible, but when I stand in different angle from the water I can see it clearly, whereas some angles offer partial ...
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3answers
3k 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 ...
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2answers
389 views

What makes a material adhesive (or sticky)?

I currently have a bandage on my arm that isn't sticking to me but definitely sticks to itself. It brought up the question: What makes a material sticky? What's happening on the molecular level? Why ...
5
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1answer
209 views

Why is a white cloud formed in the hot water from the pot when salt is added?

Why is a white cloud is formed in the hot water from the pot when salt (NaCl) is added?
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2answers
313 views

Paradox while Cooling & Heating in Air? [duplicate]

I was thinking about how asteroids get "burned" up in the upper atmosphere as they approach the earth surface due to the atmosphere of earth heating the asteroids immensely as a result of air ...
2
votes
1answer
534 views

Why is water vapor released when an empty water bottle is squeezed?

I recently came across this tutorial and wondered why vapor will come out when the cap comes off. Heres the Tutorial
20
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1answer
389 views

How many molecules rub off when I press a key?

I have a lot of questions below but my overarching questions are: Do surfaces rubbing lightly together always strip molecules off of each other? and How can we model that? Clearly the answer to the ...
0
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1answer
337 views

Should a pen be light or heavy? [closed]

Expensive pens are usually heavy. Naturally a heavy weight is not expected for an ordinary pen. But in the view of mechanics, the more the inertia the more the capability of holding the speed. Is ...
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7answers
7k 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 effort/...
3
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3answers
892 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 ...
0
votes
1answer
75 views

Does this person get electrified?

Does a person get electrified when his feet are on the floor, his right hand is holding $220~V$ and his left hand holding a piece of wood or any other insulator?
37
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2answers
1k views

Why do stickers curl?

When peeling a sticker off its base, the immediate reaction is that it curls; why is this? I am having trouble finding an answer to this. Could it be that the glued side expands upon contact with the ...
16
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4answers
7k views

Why do I always hear remote train horn at night?

This is definitely not an illusion, as many people have the same experience. I have usually lived in places miles away from train stations, which makes it unlikely to hear any train horns during the ...
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2answers
65 views

Solar stills with Wine [closed]

Is it possible to obtain more concentrated alcohol by using wine in a solar still instead of seawater? If yes, as I suspected, how does the concentration (of alcohol) of the distillate vary with time?...
7
votes
2answers
486 views

Why is it so hard to mix spaghetti with meatballs?

When I cook spaghetti with a sauce that includes meatballs or chopped vegetables, those stay in chunks and won't get uniformly mixed in the pasta. Is there a simple reason for that? Has it been ...
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6answers
1k views

Who does work while walking?

While walking the work done by friction is zero. But who does the work, actually? How someone is getting displaced? This situation also arises when someone climbs without slipping or is climbing a ...
30
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10answers
27k 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, ...
6
votes
2answers
10k views

Which force is responsible for victory in tug of war?

I'm confused: In a tug of war game on rough ground who will win? The one who applies greater force on the rope or the one who applies greater force on ground?
1
vote
1answer
504 views

Why there is a time gap between the news presenter and the field reporter?

This one has been in my mind for years, but I simply can not find any reason for this event. The Situation Imagine yourself sitting in the living room while watching television. It's 9 p.m and the ...
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3answers
124 views

Researching an automobile accident.Wondering if someone can help me as I never studied physics [closed]

I am trying do some independent research on a recent auto collision where the information released doesn't seem plausible based on the pictures that I have seen of the accidents aftermath. A 5,500lb(...
2
votes
1answer
1k views

Teflon and induction cookware

I remember once getting new Teflon (non-stick) cookware; however, when I tried this new cookware on my induction cooker the cookware did not heat up. My regular steel cookware worked just fine on the ...
0
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1answer
3k 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?
3
votes
1answer
205 views

How come these 3d glasses don't show a difference between horizontal and vertical?

I thought that modern 3d glasses work by having one lens filter horizontally polarized light, and the other filter vertically polarized light. However, I found this pair of 3d glasses at my parents' ...
4
votes
2answers
1k views

Why slightly closing your eyes let you see the rainbow colors?

So I was sitting and looked at a street lamp outside my house. It is an ordinary lamp that looks something like that: This lamp emits white light and it is about 20 meters from my house. It was ...
8
votes
1answer
696 views

Why does the majority of smoke leave when flames appear?

When I burn wood, paper, or other plant matter, where there is a flame, there generally isn't too much smoke, but it I blow the fire out, smoke starts billowing up. It billows thicker and thicker as ...
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vote
0answers
97 views

How do we get a wave pulse and wave packet/train?

Ok, If a disturbance is localized to a small part of the space for a certain time we get a wave pulse and if the source is active for time greater than to complete a single pulse we get a wave ...
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0answers
243 views

Milk-First School

I have always been struck by the huge amount of different arguments about the issue: When you make a cup of tea, the milk should be poured first or added to the cup after the tea? Wikipedia, ...