* Magnitude: Acceleration has a numerical value that represents how much the velocity changes over time.

* Direction: Acceleration also has a direction. It tells you in what direction the velocity is changing.

Example:

* A car speeding up in a straight line has an acceleration in the direction of its motion.

* A car turning a corner has an acceleration towards the center of the curve, even if its speed is constant.

Key Takeaway: Acceleration is a vector because it requires both magnitude (how much) and direction (which way) to be fully described.