Diffraction

[Shanzey]

What is the difference between constructive and destructive interference, and how do they affect electrons' behavior?

[Anna Heckler 2C]

Constructive interference describes when the waves are in phase (peaks are overlapping). When this occurs, the amplitudes of the peaks are added to create one larger wave. Destructive interference describes when the waves are out of phase. The peaks do not overlap, and the amplitudes are subtracted.

[Juliet Stephenson 4E]

Constructive interference occurs when the waves line up in-phase, so they stack on top of each other and gain energy (higher frequency, shorter wavelength). Destructive interference occurs when waves line up out of phase. Imagine that the peak of one wave is lining up with the trough of a different wave. This causes the wave to lose energy, as the waves counteract each other (lower frequency, longer wavelength). Light that has experienced constructive interference will be more energetic and transfer more energy to an electron, while light that has experienced destructive interference will be less energetic and transfer less energy to an electron.

[gferg21]

Sometimes the wavelengths can overlap but they may not have the same amplitude, and will therefore not exactly double or exactly cancel out. In these cases there is still a wave present and not a "flat line" that you would see in a diagram.

[TanveerDhaliwal3G]

Here is a good graphic to sum up the difference between Constructive and Destructive Interference:
https://cdn.britannica.com/07/62907-004-A3A6351E.jpg

[Maika Ngoie 1B]

You can think of it similar to building structure, constructive interference is when the waves are in phase, almost providing support, creating a greater amplitude of the wavelength. Destructive, however, is when the wavelengths are out of phase and opposite to one another. This causes the energy of the waves to cancel each other out.

[ramiro_romero]

Constructive diffraction results from waves in phase and destructive results from waves out of phase. Diffraction patterns result from interacting waves (the 2 types of interference previously mentioned), meaning that e- must have wavelike properties.