Modelling vs Simulation
Modelling (modeling) and simulations are two closely related computer applications which play a major role in science and engineering today. They help scientists and engineers to reduce the cost and time consumption for research. They are also useful for ordinary people to understand and be trained for something easily.
Modelling
Modeling is creating a ‘model’ which represents an object or system with its all or subset of properties. A model may be exactly the same as the original system or sometimes approximations make it deviates from the real system. As an example, a computer model of a ship may provide the 3D visualization of the ship so that user can rotate and zoom to get a clear idea of the dimensions of the ship. A mathematical model is something different from a 3D model. A mathematical model describes a system with equations
Modeling can reduce the cost of a process and make the progress faster. As an example when you need to build a ship you can create few models of it and find the best solution. This is not possible in absence of modelling because you cannot build several ships and select one in reality. Therefore present designers are able to optimize their design.
Simulation
Simulation is a technique of studying and analyzing the behavior of a real world or an imaginary system by mimicking it on a computer application. A simulation is works on a mathematical model that describes the system. In a simulation, one or more variable of the mathematical model is changed and resulted changes in other variables are observed. Simulations enable users to predict the behavior of the real world system. As an example, behavior of a ship can be simulated using a mathematical model describes the governing laws of physics (fluid statistics and dynamics). Users can change the variable such as speed, weight and observe the stability of the ship.
Simulations are also used to train people for some specific activities and react to unexpected situations. Car and flight simulators training drivers and pilots are examples of such simulations.
Simulations help designers to optimize their systems by doing necessary changes and obtain good results. They can try deferent designs while changing properties in virtual environment so that money and time can be saved. Users can run simulations slower or faster than the real world and that may helps to figure out more details.
Difference between modeling and simulation 1. Both computer modelling and simulations are computer applications which represent a real world or imaginary system. 2. Both computer modelling and simulations help designers to save time and money. 3. A simulation is changing one or more variables of a model and observing the resulted changes. 4. Although a model always tries to represent the actual system, a simulation may try to observe the results by doing impossible (in real world) changes. 5. A model can be considered as a static and a simulation can be considered as dynamic as the variables of a simulation get always changed.

Nicky says
Thank you!!!