Applies to questions related to common objects and frequently experienced effects. Typically, these questions require explaining how the laws of physics are applied to a common situation, how objects work, etc.
5
votes
4answers
183 views
Can a balloon be used as an anchor point for a pulley?
For a physics/ engineering contest, I want to use a large balloon as an anchor point for a pulley. This would allow me to raise and drop masses.
However, in testing, when I pull on the pulley the ...
2
votes
3answers
111 views
Flushing water-Is it related to Coriolis force? [duplicate]
There are videos and articles on the internet which demonstrate that water flows down a flush clockwise in Northern Hemisphere and anti-clockwise in Southern Hemisphere.
Here are a couple of links ...
2
votes
2answers
212 views
Using Electrostatic Force to Repel Dust From an Object
I have two 4,000V, 2.5mA, DC power supplies and am attempting to use them in such a way to cause a 6x4x1-inch ABS plastic object to repel dust from the ambient air and prevent this dust from settling ...
3
votes
1answer
72 views
What's the principle used in infant breath monitor devices?
Such a device consists of a sensor pad that is placed under a mattress:
What's the principle it uses to detect breathing?
1
vote
1answer
43 views
What controls the heating ability of steamers?
Pictured below is a standalone steamer used for foaming and heating milk for milk-based coffee drinks like cappuccinos and lattes. They can be filled with water up to the pressure relief incorporated ...
15
votes
11answers
1k views
Are there still 'everyday' phenomena unexplained by Physics? [closed]
There are two very famous quotes from German Nobel Laureate Albert Abraham Michelson that are remembered mainly for being extremely wrong (especially since he said them just before two major ...
1
vote
1answer
129 views
Is my electric power cord creating magnetic field when coiled?
Simple question. But I was wondering, does my mac power cord create a magnetic field when its all coiled?
14
votes
2answers
659 views
What causes ballpoint pens to write intermittently?
After a while, a ball point pen doesn't write very well anymore. It will write for a little distance, then leave a gap, then maybe write in little streaks, then maybe write properly again. It seems ...
0
votes
0answers
66 views
On a Pilates reformer, how much resistance is from springs and how much from weight of user?
Here's picture of a Pilates Reformer machine: image
How much of the force required to move the carriage is based on the resistance of the springs, and how much is based on the weight of the user? ...
6
votes
6answers
610 views
When driving uphill why can't I reach a velocity that I would have been able to maintain if I started with it?
Consider these two situations when driving on a long straight road uphill:
Starting at a high velocity $v_h$, which the car is able to maintain.
Starting at a lower velocity $v_l$, and then trying ...
1
vote
1answer
116 views
why do lightbulbs sometimes unscrew by themselves?
I've seen some light fixtures which exhibit the behavior of lightbulbs gradually unscrewing by themselves.
9
votes
3answers
226 views
Does sound propagate further in freezing weather?
A few days ago I went for a walk in the evening. We're having winter with a little snow and freezing temperatures. We're in a quiet, shallow valley with a train station about 1km from us. I heard a ...
0
votes
1answer
139 views
Confused about fire?
Im confused about fire.
The way I see it :
Heat creates (kinetic) energy in mass and this creates stronger vibrations of atoms.
When those vibrations are strong enough the electrons interact ...
2
votes
3answers
204 views
Why does smoke go inside the car if the back door is open?
Inspired by another question I wanted to ask about phenomenon that I've experienced.
We had a van with separate trunk deprtment (similar looking one below) to transport things. But some of the things ...
3
votes
4answers
399 views
Why does smoke go out the window of the car - and what if there's wind blowing instead of the car moving?
When driving a car while smoking with the window open (safety and legal issues aside), I've noticed that the smoke tends to go outside the window.
Why does the smoke go outside?
If the car is ...
7
votes
3answers
354 views
Would a bicycle stay upright if moving on a treadmill and why?
I suspect not, because moving forward (or backwards for that matter) is an important part, but I would like to confirm.
UPDATE: Clearly it's possible
...
19
votes
3answers
388 views
How much information about the scale of a waterfall can be obtained from its sound?
Is it possible to constrain the height, volume flow, or distance of a waterfall from the quantitative analysis of a high-quality recording of its sound?
As an aside, the simulated sounds of fluid ...
2
votes
1answer
146 views
What is the cause of orange sky glow?
I live in the Netherlands and recently I have been seeing an orange glow in the sky at night, in the northwestern direction. What is the cause of this? And why is it in the northwestern direction (I ...
2
votes
3answers
116 views
Why is there more steam when water is subject to less fire?
When I cook things, such as scallop and salmon, I found that the food may be more tender if I wait till the water boils (at 100 C) and immediately turn the fire lower so that the water is not bubbling ...
5
votes
0answers
196 views
Neodymium Electromagnet?
I am interface designer that occasionally steps out and does some product/concept design. The last one I'm working on is something that would require me to make a matrix of little electro magnets, and ...
5
votes
2answers
145 views
Why does motion help you balance on ice skates?
It's almost impossible to balance on a single ice skate if you're standing still. But give yourself just a little forward motion—it doesn't take very much—and it suddenly becomes easy. You can stand ...
2
votes
1answer
136 views
Do plastic shoes electrically insulate people from the ground?
I've read on the Internet that wearing plastic shoes doesn't allow electric charges we collect from our environment (PC, TV, appliances) to be earthed.
Is this reasoning correct?
0
votes
2answers
100 views
Stealing heat, or not?
Say I hook a 1KW steam engine to the steam heat in my apartment, and generate 1KW of electricity (the engine is 1KW mechanical, not 1KW thermal) from it, so I don't have to pay ConEd.
That means I ...
4
votes
0answers
127 views
Why does the milk frother on my coffee machine make so much noise?
I have a Sunbeam home espresso machine with a steam wand. The steam roars out straight from the end of the wand. When it's first placed in the cold milk it really screams! Once the milk has a bit of a ...
13
votes
1answer
259 views
Why is boiling water the second time more quiet than boiling it the first time?
First of all: This is a different question than Why is boiling water loud, then quiet?, although the answers might be similar.
When I wake up, I boil some water for a cup of tea. It happens quite ...
5
votes
0answers
187 views
Where to place a fan in order to cool a room the fastest [closed]
Imagine I have room that is very hot and it is colder outside. I want to cool it down using a fan.
Scenario 1
There is only one door. I have one fan.
Where should I put it and which way should it ...
1
vote
1answer
90 views
What are the optimal conditions to fuel your car?
I was filling my car earlier today, and noticed a sticker posted on the pump.
This pump dispenses fuel at a volumetric amount measured in standard gallons (231 cubic inches). It does not adjust ...
0
votes
0answers
79 views
How can I measure the calories consumed in daily activity? [closed]
From a nice question here:
How are the calories in food calculated?
I can roughly understand how people provide the data of calories in certain food.
However, I am still confused about 2 things.
1) ...
3
votes
1answer
111 views
How would one calculate the amount of water contained in a cloud?
So I was looking out the sky one day and I wondered how I would go about calculating how much water was contained in a cloud. I figured the following simple outline
1) We need to roughly know how big ...
2
votes
4answers
147 views
Is a flawless trick die possible?
Trick dice have been used in gambling and magic shows. These are dice that, when rolled, will land with a preferred number facing upwards. This makes the result of rolling the dice non-random.
I was ...
1
vote
4answers
351 views
Physics of a burning log of firewood
According to my knowledge, heat is nothing but the result of the vibrations of atoms and molecules. I guess this mean that in heating up a gas or liquid, we are increasing the rate at which the ...
0
votes
2answers
306 views
Center of gravity of vehicle and vehicle performance
I am interested to know how does CG of vehicle plays role in the Fuel economy and the vehicle performance. Does CG of vehicle has anything to do while accelerating of your vehicle. I am a student, ...
6
votes
4answers
352 views
What happens when we cut objects?
What is the role of the molecular bonds in the process of cutting something? What the one of the Pauli exclusion principle, responsible for the "hardness" of matter?
Moreover, is all the energy ...
6
votes
1answer
131 views
What is the angle at which water is splashed when a vehicle tyre rides in water on the road?
I would like to know the following:
What is the angle at which water gets splashed when I ride my vehicle through a water on the road?
How does angle of water varies with speed?
What is the relation ...
1
vote
1answer
359 views
What exactly is a Fluorescent lamp?
A fluorescent tube (home-based) works on the principle of discharge of electricity through gases, as far as I can tell (I don't know much about cathode rays or gas discharge)
What happens inside the ...
0
votes
1answer
150 views
Do arXiv links last for the forseeable future? [closed]
If I give someone an arXiv link, say http://arxiv.org/abs/0707.0118 , will this link last for the foreseeable future?
4
votes
2answers
367 views
Why does the higher of two medical IV bags empties first?
I'm a nurse, so my physics background is about that of a lay person. Please explain on that level. Ordinarily an Intravenous (IV) fluid bag is one liter. An IV piggyback is usually 2500ml. usually the ...
3
votes
1answer
119 views
Why do beverages taste different based on how cold they are? [closed]
Why does temperature effect the taste of beverages?
Specifically, how does the temperature for example mask certain tastes ie filtered vs unfiltered water taste very similar at colder temp and Is ...
0
votes
1answer
151 views
Why does the water-pressure of my shower fall if I hold the shower head high?
I live in a very old house - build 1902 - in the 4th floor in the city of Karlsruhe (Germany). I have a shower and the gas-heater for the water is in it:
If I hold the shower head over some height ...
3
votes
2answers
281 views
Why are coke bottles that much fizzier if you shake them?
We've all been there: you drop your bottle of soda at some point and when you try to open it, it bursts into foam.
My question is, then: why does shaking a carbonated drink make the dissolved gas ...
5
votes
1answer
269 views
Why do wheels appear to revolve opposite to the direction they are rotating?
When viewing cars that are driving along side of us, sometimes their wheels appear to be turning backwards even though they are traveling in the same direction as our car. Why do they look that way?
0
votes
2answers
304 views
Is there a physical reason steel balls are not suitable to play billiards with?
Steel is an elastic matter and is often used when demonstrating elastic collisions. We also make springs from it.
Due to these properties and for its relative low price, it seems obvious to me to ...
0
votes
0answers
71 views
How and where is the information which constitutes memories stored in our brain? [closed]
I am wondering if the information was stored as in computers, with a sort of condensators system, but this would imply a certain discretization, and seems to be too restrictive.
Therefore, how the ...
2
votes
2answers
398 views
A wobbly pan on an induction cooker, is it less effective?
According to the Wikipedia, one of the limitations of the induction cooker is that the bottom surface of the pot should be flat.
Accordingly, I commented on a question on Seasoned Advise, but I'd ...
1
vote
1answer
136 views
Physics of Fireworks
This evening I saw the 4th July classic Fireworks in San Diego, and I was wondering about the most physical picture of what was happening. Does anyone have a good way to explain the detailed physical ...
19
votes
3answers
580 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 ...
9
votes
1answer
842 views
Why does paper become transparent when smeared with oil but not (so much) with water?
When I smear oil onto a scrap of paper and rub it in, the paper becomes quite transparent; but when I attempt the same with water it doesn't as much. Why?
7
votes
2answers
227 views
Why is paper more frangible when it is wet?
My four-year-old daughter asked me why paper tends to fall apart when wet, and I wasn't sure. I speculated that the water lubricates the paper fibers so that they can untangle and separate more ...
4
votes
2answers
213 views
How can one feel cold without touching it?
Let me explain.
My shower is inconsistant in how hot it gets. Whenever I turn on the shower, I always put my hand really close to the water, but not touching it, so I can feel the heat radiate from ...
1
vote
1answer
303 views
What forces act on a person sitting in a chair with wheels when they push off another stationary object
What is slowing me down when I push off my desk?
What are the "Major" contributors? and
Does how hard I push with one hand (or with two hands) make a
significant difference?
