To measure the velocity of an object, you need the object's displacement and the time interval during which the displacement occurred. Displacement is the change in position of an object, and time interval is the duration of time during which the displacement occurs.

Once you have these two measurements, you can calculate velocity using the following formula:

```

velocity = displacement / time interval

```

Velocity is a vector quantity, which means that it has both magnitude and direction. The magnitude of velocity is the speed of the object, and the direction of velocity is the direction in which the object is moving.

To measure displacement, you can use a variety of methods, such as a ruler, a tape measure, or a motion detector. To measure time interval, you can use a stopwatch, a clock, or a video camera.

Once you have collected your data, you can use the formula above to calculate the velocity of the object.