alhamra.... asks about Lab skills.

[YT2095]

(moved from Experiments thread)

 

here`s the place to add/list any quick and easy experiments that can be done either at home or with simple equipment.

this is NOT a thread for Chat, and all experiments entered here MUST BE according to the SFN safety/legality regulations.

 

please keep all entries as complete and exact as possible.

 

where possible provide links with pictures (not a requirement).

 

All subjects are welcome, Chemistry, Physics, Biology, Psychology etc...

 

single post... single experiment

 

i am very poor in the lab skills.can anybody give me the tips:what should i followed to improve my skills?

[insane_alien]

in what area? i mean , you know a lot of skills are required i nthe lab. a few specific questions would help.

[YT2095]

Practice makes perfect (or at least reasonably Competent).

[swansont]

What kind of lab? Physics, chem or biology?

[insane_alien]

its YT, its gonna be chem.

[Cap'n Refsmmat]

It's not YT asking for the help, it's alhamra.

[Klaynos]

Well a big thing in the lab I work in is optical alignment, and it's basically practise makes perfect :|

[swansont]

Well a big thing in the lab I work in is optical alignment, and it's basically practise makes perfect :|

 

But within that there are tricks, or things that may not be obvious to a beginner.

 

One system I worked on used a beat-note between two lasers in order to lock them together at some offset frequency. In order to get a good signal, the two beams must be copropagating and well-aligned, and there are many degrees of freedom, which makes it tough. What I did was to remove the detector and make sure the spots overlapped several meters away (on the wall). If the everlap was good at that distance, the signal on the detector would be good.

[Klaynos]

Yeah that's true swansont, most of the stuff I've been doing in the last year (and all in the last 6 months) has been with white light sources which are a b**h to deal with when you need them as collimated as possible to pass through your polariser :|

[swansont]

Another "trick" that a beginner might not know is that you can spatially filter a beam to remove the higher-order spatial modes of light to give yourself something that looks more like a Gaussian beam. Construct a 1:1 telescope. At the focal point, the beam is a transform of the spatial quality — the Gaussian part is most tightly focused, with the higher-order modes (anything that has a spatial periodicity within the beam) being farther out. So you put a pinhole at the focal point, and only the high-quality light gets through. Important if you're relying on good beam quality.

[Klaynos]

Another "trick" that a beginner might not know is that you can spatially filter a beam to remove the higher-order spatial modes of light to give yourself something that looks more like a Gaussian beam. Construct a 1:1 telescope. At the focal point, the beam is a transform of the spatial quality — the Gaussian part is most tightly focused, with the higher-order modes (anything that has a spatial periodicity within the beam) being farther out. So you put a pinhole at the focal point, and only the high-quality light gets through. Important if you're relying on good beam quality.

 

The first time we tried that the pinhole started smoking.... We had to build a special one...

 

One very useful trick is using the reflected light to line up on the previous optic...

[swansont]

And another one: When you use plano-convex/concave lenses, put the parallel beam onto the curved surface to reduce aberration.