# Is it possible to reproduce Double-slit experiment by myself at home?

I want to reproduce this experiment by myself. What I need for this. What parameters of slits and laser/another light source it needs? Is it possible to make DIY-detector?

-

The detector could be a whole separate question, especially if you are thinking of building a photomultiplier or something. Honestly, a successful experiment will show itself qualitatively upon visual inspection. If you want a more quantitative analysis, perhaps taking a RAW picture and looking at pixel values will suffice. – Chris White Feb 15 at 19:24
– Raindrop Feb 16 at 18:18

## 3 Answers

It's actually quite easy to perform the experiment in the comfort of your own home. The simplest setup I have seen (as depicted in this, and other youtube videos) is two use a laser pointer and pencil lead, but you can certainly be more systematic and cut slits in some opaque material as well.

I would encourage you to experiment to answer the question of how far apart the slits need to be etc., but some basic math behind this is as follows: If the slits are a distance $d$ apart, if the light has wavelength $\lambda$, and if the distance between the slits and the screen is $L$, then the spacing $\Delta y$ between successive fringes on the wall will approximately be $$\Delta y \approx \frac{\lambda L}{d}$$ So let's say the laser is red so that $\lambda\approx 700 \mathrm{nm}$, the slits are $1\,\mathrm{mm}$ apart, and the screen is $1.5\,\mathrm m$ away from the slits, then we have $$\Delta y \approx \frac{(700\,\mathrm{nm})(1.5\,\mathrm{m})}{1\,\mathrm{mm}} = 1.05\,\mathrm{mm}$$ So you can actually try this and see if your results agree! (I might actually try this myself come to think of it; thanks for the question!)

Cheers!

-

2
Gah. You beat me by about a minute. – Emilio Pisanty Feb 15 at 17:05
Haha...apologies Emilio. – joshphysics Feb 15 at 17:05

2
– Emilio Pisanty Feb 15 at 17:07
What's about detector near one slit? – Robotex Feb 15 at 18:06
I would add from my own experience that cutting slits in an opaque material often produces slits that are not entirely negligible in width (compared to $d$), so there may be a broad single-slit pattern modulating the double-slit pattern that is sought. – Chris White Feb 15 at 19:21
show 1 more comment

Laser pointer, nit comb, bit of cardboard from a cereal box to control the number of slits. Works perfectly!

-

Absolutely, though the result does depend somewhat upon your definition of "at home".

Simply seeing the interference pattern is as simple as a laser pointer and a few narrow apertures (see the other answer(s))

People have successfully even done single-photon interference at home!

-
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 8, "mathjax_display_tex": 2, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "github"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "english_confidence": 0.9289182424545288, "perplexity_flag": "middle"}