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Questions tagged [home-experiment]

questions concerning measurements, experiments, and activities that demonstrate physics and are safe to do at home, require at most one tool or ingredient not readily available, and can be interpreted or analyzed on one sheet of paper with accessible math.

Notes on Safety

  • Some of our audience might be children, so make it clear what projects may call for adult supervision.
  • It is best to list even the obvious dangers and point the reader towards ways to avoid or mitigate them.
777 questions
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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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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
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How can you weigh your own head in an accurate way?

I read some methods but they're not accurate. They use the Archimedes principle and they assume uniform body density which of course is far from true. Others are silly like this one: Take a knife then remove your head. Place it on some scale Take…
user5402
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3 answers

Why is the vibration in my wire acting so oddly?

I was soldering a very thin wire today, and when I had one end firmly soldered, I accidentally bumped the wire diagonally with my tweezers. What I'd expect to happen is that the wire oscillates for a little while in one axis, then stops. However,…
0xDBFB7
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Why does a candle blow out when we blow on it? Our breath is 16% oxygen and only 4% CO2

Don't say that a layer of carbon dioxide covers the flame, because our breath has more oxygen than carbon dioxide. Also, our breath does not extinguish the flame by cooling it as it is itself warmer than the coolness required to extinguish it. So…
Prem
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72
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17 answers

What is the simplest way to prove the Earth is round?

Assume you've come in contact with a tribe of people cut off from the rest of the world, or you've gone back in time several thousand years, or (more likely) you've got a numbskull cousin. How would you prove that the Earth is, in fact, round?
tQuarella
72
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2 answers

How to measure the wavelength of a laser pointer?

I'm working on something and I need to know the wavelength of the laser pointer that I'm using. Can you suggest me a way, using some optics formulae, or anything else to calculate the wavelength?
user82920
71
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3 answers

Why does water falling slowly from a tap bend inwards?

This is something anyone could easily verify. When we open a tap slowly, water bends inwards (towards the axis) while maintaining its laminar flow. After a certain height below the opening, the flow becomes turbulent. I've approximately illustrated…
Vishnu
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6 answers

Why does a ping pong ball bounce higher when it is dropped together with a cup of water?

Setup: an official ping pong ball is floating inside a party plastic cup filled with clean water, which is then dropped from a certain height onto a soft mat. Observation: the ping pong ball shoots up to a height which is much higher than its…
user6760
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5 answers

Why do grapes in a microwave oven produce plasma?

Some of you may know this experiment (Grape + Microwave oven = Plasma video link): take a grape that you almost split in two parts, letting just a tiny piece of skin making a link between each half-part. put that in a microwave oven, and few…
JBE
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Home experiments to derive the speed of light?

Are there any experiments I can do to derive the speed of light with only common household tools?
Justin L.
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3 answers

Why is Microwaved mac & cheese burnt where they touch?

After reheating cold about 1.5 oz. of Annie's Mac & Cheese shells for 15 seconds on high power in the microwave, the mac & cheese was burnt black only at certain points where the pasta is touching each other. Does anyone have an idea of what might…
Zooky
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5 answers

What causes this pattern of sunlight reflected off a table leg?

My friend noticed an interference-like pattern around the table leg. However, we do know that interference patterns of sunlight produces rainbow colours. What seems to be happening here?
Luke
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41
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2 answers

Why does laser light not affect glowing materials?

I have this childrens rubber ball which glows in the dark after it's exposed to light. I "charge" it with a flash light then play with my dogs at night. I thought to try a very intense green laser, and see how the ball reacted. The laser light had…
Michael
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Classic home experiments for an 8-year-old child

My 8-year-old daughter's school report says that she's good at understanding the basic science she's doing, but she's having trouble seeing how experimental results lead to conclusions. Specifically, it says she struggles to appreciate how changing…
Bob Tway
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