In this simulation you can adjust the wavelength of light striking a single slit. The width of the slit is also under your control. Light diffracts as it passes through the slit, and then strikes a surface near the top of your screen. You can also control the distance between the slit and the surface.
How does decreasing the wavelength of light affect the diffraction pattern? Make a prediction and then change the wavelength to 400 nm to check.
The diffraction also depends on the slit width. How will decreasing the slit width change the pattern? Use the simulation to check your prediction.
Yet another factor is the distance between the slit and the surface. How will increasing the distance change the diffraction pattern? Check it out.
Diffraction is still important in two-slit interference. What would happen if you opened a second slit the same width as the first? Select the two-slit mode of the simulation to find out.
What feature of the new pattern is controlled by the slit separation? Make a prediction and use the simulation to see if you are correct.
Does changing the wavelength, slit width, or distance to the surface in the double slit case have the same effect on the pattern as in the single-slit case?