View an animation explaining how small things like electrons and protons can behave like particles and sometimes like waves

We see particle-like behavior every day. Drop a ball on the ground and it follows a single trajectory. Leave your giraffe parked on the street, and when you come back, it's still there. Just one giraffe. And we see wave behavior too. Toot your horn, and waves spread out through the air, carrying sound to the ears of anyone around. Or drive a boat through water, and waves travel outwards along the surface.

But when it comes to the physics of the very small, what we see is a wave-particle duality. Sometimes the very small things-- we're talking electrons and protons here-- behave like particles and sometimes they behave like waves. Flip-floppers. For example, if you release an electron, it'll travel outward as a wave through the room. But when it hits the wall, it will only hit in one place. You started with one electron, after all.

So what if sound had a wave-particle duality? When you shouted, the sound waves would spread outwards in all directions but only one person could hear what you said, or when you drove your boat through the water, the waves would travel like normal but only hit the shore in one place. Now that would make for some pretty boring surfing.