Young's Double Slit Experiment
Why Physics Stack Exchange recommends it
Physics Stack Exchange answerers point people to it as a cheap, easy-to-copy setup for seeing double-slit interference at home.
Recommended by 2 people across 2 different months, 2012 to 2014.
What it is
A 70-second home demonstration of Young's double slit experiment, using a laser pointer shone through the gap between two pencil leads onto a wall. It shows the resulting interference pattern, and the description notes that a single slit also produces interference but without the amplitude envelope.
What people said
Recommends Alan Rominger · 2012-12 · Physics Stack Exchange · on “Tried to do the double slit experiment, failed. Why?”
Here is an helpful tutorial for comparison to your attempt. (I'm sure I saw this on Physics SE but I can't find it now). [this video] I used this method a little while ago and was able to get results. It uses mechanical pencil lead and an over the counter laser, making it a very cheap experiment. Let's compare the parameters of the experiments. Slit spacing distance: 0.5 mm by the manufacture of the lead / 0.5-0.8 mm for yours Between slits and the wall: about 1 m for video / inches to 8 feet for yours Slit size: about 0.5 mm with the lead / unknown for yours Between lasers and slit: about 1 foot for video / inches to 20 feet for yours laser power: 5 mW for what I did / 200-250 mW for yours From
Recommends joshphysics · 2013-02 · Physics Stack Exchange · on “Is it possible to reproduce Double-slit experiment by myself at home?”
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 [this video] , and other youtube videos) is to 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
Cites Sensebe · 2014-04 · Physics Stack Exchange · on “Young double slit experiment without first slit”
Yes, you will see interference pattern, provided the slit widths and their separation are appropriate. Look here [this video] . If laser beam width is greater than the separation of the slits, the beam may split and might form interference pattern. It is to be noted that particles of appreciable size (coming in the path of laser) will also scatter light according to Tyndall effect.