Central differencing scheme

Central differencing scheme is a way of calculating the change in something over time. Imagine you have a ball which is moving across a table, you could use the central differencing scheme to work out how the ball's speed is changing. To do this we measure the ball's position at two different times (time 1 and time 2) and then work out the difference between the two. This difference shows us how much the ball has moved over the time period between time 1 and time 2, and so helps us to calculate the ball's speed.