What's the main difference between "velocity" and "speed?"

Native speaker’s answer
Rebecca
Good question. "Speed" is the rate at which an object moves along a distance, while velocity is the rate and direction of an object's movement. Thus, you can think of velocity as being different in that it is speed with direction. They are two different concepts in science, but are often used interchangeably in casual contexts. Ex: The train travels at a speed of 200 km per hour. Ex: Space rockets travel at an incredibly high velocity upwards.