Reputation
18,724
Next privilege 20,000 Rep.
Access 'trusted user' tools
Badges
1 30 60
Newest
 Good Answer
Impact
~1.2m people reached

Sep
19
answered Can you record sound through vacuum? Like this: (object)(vacuum)(object)
Sep
19
answered Radioisotope beta decay generator
Sep
17
comment Why vacuuming an air chamber is much slower than vacuuming an argon chamber?
@Sparkler, non-micro drops stay liquid and gradually boil new water vapor, especially when they are wetting large surfaces like insulation blankets
Sep
17
comment Measuring focal length of complex lens
Interesting. I don't have the lab setup to immediately try this but it is worth considering.
Sep
14
comment How the car keys prevent the shock caused by Static Electricity
Dry pure rubber in a materials data book is an insulator. Car tires are a mix of rubber, carbon (to make them black) steel wires etc. and the surface of a real tire has a film of water + salts + dirt. The surface area of the tire and the contact area with the ground is relatively large. So real car tires in the real world (especially in winter driving conditions) are quite a good ground path.
Sep
13
comment Using nuclear devices to terraform Mars: Elon Musk's nuclear proposal?
So Mars needs carbon emissions and global warming the obvious first step is to ban the Tesla
Sep
10
comment Measuring focal length of complex lens
@Floris, yes lens is on a camera prefocussed at 1m. It is a 12mm f/4 approx +/-150mm dof. Using a bar chart target so I can fit sub-pixel positions of a pattern even out of focus.
Sep
10
comment Measuring focal length of complex lens
@CuriousOne. In this case the complex computerised measurement system was also built by me. So I distrust; me , software, and software built by me!
Sep
10
revised Measuring focal length of complex lens
added 5 characters in body
Sep
10
comment Measuring focal length of complex lens
@CuriousOne - the experiment is a one off to verify the complex system which tests production units. So it is the number I need.
Sep
10
asked Measuring focal length of complex lens
Aug
30
comment What invisible flicker do different types of light bulbs have?
@jameslarge - you can turn them on and off very quickly. Because of their small size and high efficency the amount of energy in the diode is small and so you can change it's state much more quickly than eg. a filamanet bulb
Aug
29
answered Does a switched on power socket consume electricity?
Aug
29
comment Using a laser to overhear a room conversation
Split the beam, send half to the window and interfere the reflected part with the reference arm. Count fringes and 1 fringe = 1/2 wavelength change in distance to window. Or modulate the laser and track the phase difference of the transmitted/returned signal like a "disto" laser measuring tape. I thought in your original answer you meant you would measure the color change of the returned signal to detect a few cm/s shift imposed on the speed of light and integrate the velocity of the window to get position. I'm not sure it is simple to get a laser with that much wavelength stability.
Aug
28
comment Using a laser to overhear a room conversation
Would you need to measure the speed of the window or merely the position wrt to time. I'm not sure I would use doppler as much as simply an interferometer (ie a phase distance measurement)
Aug
28
awarded  visible-light
Aug
14
revised Can a GPS system detect the decline in the rotational velocity of the Earth?
added 107 characters in body
Aug
12
answered Colour changing material/ink
Aug
11
answered Can a GPS system detect the decline in the rotational velocity of the Earth?
Aug
9
answered thin film interference of light