computers
Scientists create models with computers. Computers can handle enormous amounts of data. This can more accurately represent the real situation. For example, Earths climate depends on an enormous number of factors. Climate models can predict how climate will change as certain gases are added to the atmosphere. To test how good a model is, scientists might start a test run at a time in the past. If the model can predict the present it is probably a good model. It is more likely to be accurate when predicting the future.