Scientists use models and simulations to study complex systems and phenomena that are difficult or impossible to observe directly. Models and simulations allow scientists to test hypotheses, make predictions, and explore different scenarios without the need for expensive or risky experiments. They can also help identify gaps in our knowledge and guide future research. Models and simulations are used in many areas of science, including physics, biology, climate science, and engineering. They are essential tools for advancing our understanding of the world and solving real-world problems.