Constructive vs. Destructive Interference [ENDORSED]

[MichelleKaku1H]

Can someone please explain the difference between the two? And what exactly is diffraction? I'm sorry, I'm really confused.

[Cam Bear 2F]

Diffraction just refers to what happens when a wave encounters an object and bends around it. Constructive Interference is when two waves meet and the crests (top of the wave) of both waves are aligned so the resulting wave increases in amplitude. The two waves converge into a bigger wave, so to speak. Destructive interference is when the waves meet and they aren't aligned. So one wave's crest will meet the other waves trough (bottom of the wave) resulting in a smaller amplitude when they combine.

[Michelle Lee 2E]

Cam Bear 3G,
Your response helped me understand the general differences. However, I was wondering if you had any insight to some new questions I have on Constructive and Destructive Interference.

What are we supposed to understand about constructive and deductive interference? Do we need to understand how to get to the sum of the altitudes of the components? Do we just need to know how it is a basis for various techniques of studying matter or what else of it do we need to understand?
Also, in figure 1.19 [the diagram], I understand that when the electromagnetic radiation wave peaks interfere with each other (when the waves' peaks hit one another), there is constructive interference. What exactly happens where the waves interfere constructively and interfere destructively?

[Chem_Mod]

Constructively, the light waves combine to create a more intense wave. This happens because the crests of the wave overlap, like how waves in water would, to make a larger wave. Destructively, the valley of the wave combines with the crest of another wave to cancel out, leading to no light.

[mayasinha1B]

Diffraction also results from two or more waves interacting constructively or destructively.