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.
20
votes
8answers
2k views
Why doesn't the bike fall if going with a high speed?
Why does the bike fall when its speed is very low or close to zero and is balanced when going with a high speed?
3
votes
2answers
545 views
Relating milliampere-hours to watt-hours for batteries
I've seen many batteries that are measured in milliampere hours (mAh), while others are measured in watt hours (wh). How can I convert them between each other so that I can actually compare them? It's ...
5
votes
1answer
981 views
Why is boiling water loud, then quiet?
Water in my electric kettle makes the most noise sixty to ninety seconds before the water comes to a full boil. I have been fooled many times by the noisy kettle, only to discover that the water was ...
19
votes
3answers
554 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
785 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?
1
vote
1answer
78 views
Calculate the distance between two points from iPhone Camera
I want to calculate the distance between two objects using an iPhone camera.
Suppose I'm standing with my iPhone 10 feet away from the objects. Now, I want to calculate the distance between those ...
8
votes
3answers
529 views
How hot is the water in the pot?
Question: How hot is the water in the pot? More precisely speaking, how can I get a temperature of the water as a function of time a priori?
Background & My attempt: Recently I started spend ...
3
votes
4answers
357 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 ...
4
votes
3answers
152 views
Does more rain strike a vehicle while moving or while stopped (or neither)? [duplicate]
Assume there is a rainstorm, and the rain falling over the entire subject area is perfectly, uniformly distributed. Now assume there are two identical cars in this area. One is standing still, and ...
4
votes
4answers
808 views
How does radio receives signal from particular station?
When you tune your radio (digital or analog) to receive say 100 MHz frequency and while in the environment there are hundreds of channels everywhere around the radio. How does it chooses to receive ...
3
votes
1answer
118 views
Why does the bubbling of a soda bottle pulsate?
If I take a bottle of carbonated water and open the cap slightly to allow the gas to escape, there will be a sudden rush of bubbles foaming to the top of the liquid for a few seconds, then a partial ...
1
vote
1answer
129 views
Settling of rice as it's cooked
I couldn't think of a better title because I'm not sure what's going on with this phenomenon--someone who has an answer, please edit to fit this better.
I noticed that when I cook rice, at some point ...
13
votes
1answer
246 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 ...
9
votes
4answers
638 views
Does it matter how you order your tug-of-war participants?
In a tug-of-war match today, my summer camp students were very concerned about putting the biggest people at the back of the rope. Is there any advantage to this strategy?
4
votes
2answers
235 views
Why do books have dog ears?
I googled the question and found no explanation. It seems that dog ears are inevitable (for paperbacks, notably) even if you've always been careful. From my experience, they are about equally likely ...
3
votes
3answers
298 views
Is there more energy in the collapse of a cavitation bubble than the energy required to create the bubble in the first place?
The following does not include all scientific details and parameters, only a common summary of "thoughts". What is scientifically wrong with this summary?
When you take your beer and tap the top ...
2
votes
2answers
536 views
Please recommend a good book about physics for young child (elementary school aged)
I'm looking for a book that would be appropriate for an advanced elementary school aged kids (say, 6-11 YO) describing the basics of physics (or sciences in general) in entertaining way.
The ...
