Tagged Questions
1
vote
0answers
78 views
Easy question about magnetism?
I have to build a simple electric motor by attaching a magnet to a battery, extending the terminals of the battery (with stiff wires so they could act as supports), and placing a coil of wire on top ...
1
vote
1answer
64 views
A good theoretical approximation for a magnetically damped pendulum
In a laboratory course we had to perform an experiment with a pendulum (just an iron weight on a wire) and play around for some time with its wire's length and so on.
This was quite boring and we ...
-1
votes
1answer
85 views
Funny classroom experiments [closed]
I'd like to perform some weekly classroom experiments to keep my students interested and curious about everyday physics. Those experiments have to be quite easy to set up and not too easy to ...
0
votes
0answers
76 views
Superconductors for sale? [closed]
Does anyone know where I can purchase superconductors for a school presentation? I don't need a whole kit, just the disk itself. Thanks.
3
votes
1answer
165 views
Revealing Electric field lines through Grass seeds in mineral oil
In one of Walter Lewin's famous lectures, he takes a small container almost completely filled with mineral oil and grass seeds (I'll keep looking for the video to link to it). He connects two ...
2
votes
0answers
54 views
How can I determine the type of magnet used in a DC motor?
I repair electrical motors in a workshop and sometimes I must repair permanent magnet DC motors and other motors that use permanent magnets. I need to specify type of permanent magnet (Ferrite or ...
4
votes
1answer
72 views
Can I find the frequency generated by tapping a battery on a coin?
According To How Stuff Works , if you tap a 9 volt battery on a coin it will transmit Radio waves. I was wondering, because I don't have a radio with me at the moment, Is there a way I could discover ...
3
votes
2answers
83 views
Why don't Microwave ovens use more energetic EM radiation?
Because in theory, visible light contains more energy than the microwaves actually used to cook your food.
1) Does it have to do with resonance frequency of the $H_2O$ molecule?
2) How can ...
5
votes
3answers
1k views
Rough, easy DIY method of measuring magnetic field strength
How to easily, using standard DIY equipment measure the strength of magnetic field generated by a permanent magnet?
Narrowing down the "loose language" of the above:
strength of magnetic field: ...
0
votes
1answer
312 views
Inductance - Sign convention problem…
My problem is with a circuit containing a resistor of suitable resistance $R$ and a solenoid.
At time $t<0$, there was a battery that created a current in the circuit and at $t=0$, the battery is ...
2
votes
1answer
51 views
Does a microwave resonantly excite the rotational levels when cooking?
Wikipedia states there is no resonance absorption, but says at the same time that the molecules are oscillating like dipoles, which is kind of the same if you are exciting the rotational levels ?
The ...
2
votes
2answers
207 views
Demonstrate magnets adhere to conservation of energy pursuant to the laws of thermodynamics
I am looking for a way to demonstrate that magnets adhere to the laws of thermodynamics, in particular the requirement that energy in a closed system be conserved.
To adhere to the requirement that ...
3
votes
1answer
779 views
Why is the lid of the cookware kept on induction cooker not hot?
Induction cookware cooks food by inducing an electro magnetic field in the ferro-magnetic cookware. Since iron offers a lot of resistance to the current, the current is converted into heat in the ...
4
votes
1answer
111 views
How can there be a path to ground with thick shoes and a carpet?
I'm connecting a test light to one pin of an halogen lamp. When I touch the metallic part on the back of the test light, the light glows, as it is supposed to. However, I have thick shoes and I am ...
2
votes
3answers
676 views
How to make a small tokamak?
$\require{mhchem}$I made a fusor once, like the easy science project: deuterium-deuterium ones, but they're really inefficient. I was wondering if it would be possible to make a small tokamak; not one ...
3
votes
2answers
4k views
How do you magnetize an object?
How can I go about magnetizing something? Specifically, a whole bunch of BB's. I want to try this so that I could make a cheaper version of the Bucky Balls product. Even if I can't replicate Bucky ...
28
votes
13answers
7k views
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?
