We will not talk about paint flow test or wool tufts test anymore because it is a fairly simple test, we will talk about the quantitative prediction of EHP from a model experiment. So, what are the requirements of a model experiment? There are two kinds of similarities we will be looking at when we conduct a model experiment. As we have seen the Froude similarity is the basis of model experiments, which includes geometric similarity between the model and the ship that means, every linear dimension of the ship, of the model, should be directly proportional to the linear dimension of the ship.