1. Change in Speed:

* Increasing Speed: If an object's speed increases over time, it's accelerating. Think of a car speeding up.

* Decreasing Speed: Even slowing down is considered acceleration, specifically *deceleration*. This is because the object's velocity is changing (in this case, decreasing). Imagine a car coming to a stop at a red light.

2. Change in Direction:

* Turning: Even if an object maintains a constant speed, changing its direction means its velocity is changing. This means it's accelerating. Imagine a car going around a curve.

3. Combinations of Both:

* Most real-world situations: Objects often accelerate by changing both their speed and direction simultaneously. Think of a car speeding up while turning.

Key Point:

* Acceleration is about the rate of change in velocity, not just speed. Velocity includes both speed and direction.

Examples of Acceleration:

* A ball thrown upwards, slowing down as it rises.

* A roller coaster going around a loop-de-loop.

* A rocket launching into space.

* A car braking to a stop.

Let me know if you'd like more detail on any specific type of acceleration!