Concerns the application of the laws of physics to analyze common situations encountered in everyday life.
Questions tagged [everyday-life]
2358 questions
830
votes
23 answers
Cooling a cup of coffee with help of a spoon
During breakfast with my colleagues, a question popped into my head: What is the fastest method to cool a cup of coffee, if your only available instrument is a spoon? A qualitative answer would be nice, but if we could find a mathematical model or…
fortran
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546
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8 answers
Can I compute the mass of a coin based on the sound of its fall?
The other day, I bumped my bookshelf and a coin fell down. This gave me an idea. Is it possible to compute the mass of a coin, based on the sound emitted when it falls? I think that there should be a way to do it. But how?
Vinicius L. Beserra
- 5,357
526
votes
6 answers
How does light bend around my finger tip?
When I close one eye and put the tip of my finger near my open eye, it seems as if the light from the background image bends around my finger slightly, warping the image near the edges of my blurry fingertip. What causes this? Is it the heat from my…
Daniel A.A. Pelsmaeker
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376
votes
29 answers
Why are mirror images flipped horizontally but not vertically?
Why is it that when you look in the mirror left and right directions appear flipped, but not the up and down?
Arlen
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310
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2 answers
Why do ballpoint pens write better on pages that have pages below them?
If I write on the starting page of a notebook, it will write well. But when there are few or no pages below the page where I am writing, the pen will not write well. Why does this happen?
Ram Keswani
- 2,249
279
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12 answers
Why are four-legged chairs so common?
Four-legged chairs are by far the most common form of chair. However, only three legs are necessary to maintain stability whilst sitting on the chair. If the chair were to tilt, then with both a four-legged and three-legged chair, there is only one…
Karnivaurus
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274
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8 answers
Does Earth really have two high-tide bulges on opposite sides?
The bit that makes sense – tidal forces My physics teacher explained that most tidal effect is caused by the Moon rotating around the Earth, and some also by the Sun. They said that in the Earth - Moon system, the bodies are in free-fall about each…
Benjohn
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254
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8 answers
How do towels stay on hooks?
Towels (and coats) are often stored on hooks, like this: To the untrained eye, it looks like the towel will slide off from its own weight. The hook usually angles upwards slightly, but a towel does not have any "handle" to string around and hang on…
Caleb Stanford
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1 answer
Strange ice found in my garden
This morning I found a really strange ice formation in my garden. I can't figure out how it appeared, because there was nothing above. The night was particularly cold (Belgium). To give an idea, it has the size of a common mouse (5 cm of Height and…
snoob dogg
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205
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8 answers
Why do we bend a book to keep it straight?
I noticed that I have been bending my book all along, when I was reading it with one hand. This also works for plane flexible sheets of any material. Illustration using an A4 sheet Without bending the sheet: With a bend along perpendicular axis How…
Certified human
- 13,907
204
votes
21 answers
Given Newton's third law, why are things capable of moving?
Given Newton's third law, why is there motion at all? Should not all forces even themselves out, so nothing moves at all? When I push a table using my finger, the table applies the same force onto my finger like my finger does on the table just with…
user16458
- 2,083
202
votes
3 answers
Surviving under water in air bubble
An incredible news story today is about a man who survived for two days at the bottom of the sea (~30 m deep) in a capsized boat, in an air bubble that formed in a corner of the boat. He was eventually rescued by divers who came to retrieve dead…
Maxim Umansky
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190
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14 answers
Why does holding something up cost energy while no work is being done?
I read the definition of work as $$W ~=~ \vec{F} \cdot \vec{d}$$ $$\text{ Work = (Force) $\cdot$ (Distance)}.$$ If a book is there on the table, no work is done as no distance is covered. If I hold up a book in my hand and my arm is stretched, if no…
SMUsamaShah
- 5,547
189
votes
8 answers
Why do shadows from the sun join each other when near enough?
I was laying on my bed, reading a book when the sun shone through the windows on my left. I happened to look at the wall on my right and noticed this very strange effect. The shadow of my elbow, when near the pages of the book, joined up with the…
turnip
- 3,778
181
votes
2 answers
When separating an Oreo cookie, why does the cream stick to just one side only?
There is probably some reason for this, but I can't figure out what it is. I agree that it probably doesn't happen 100% of the time, but most all of the time, the cream is clinging to just one of the cookie sides.
Jiminion
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