Scientists Say: Model

Model (noun, “MAH-del”)

A model is a representation of how something in the real world works. Scientists use models to ask questions, make predictions, explain phenomena and test our current knowledge. Scientists also use models to share their ideas with others.

Some models are physical objects. A model airplane represents the shape and appearance of a real aircraft. A handheld model of a cell might show the cellular machinery that makes that cell work.

Some models are computer programs. Computer models make it possible to predict how a system will respond when parts of the system change. Climate scientists might use computer models of Earth to simulate how our planet would change in different scenarios. For example, what will happen in 10 years if we continue burning fossil fuels at the current rate? What would happen if we cut our consumption of fossil fuels in half? Running models of such scenarios can help predict the outcomes. That helps us decide the best course of action.

Many models are conceptual. That means they exist as a way of thinking about something. Our current understanding of genetics — such as the role of DNA and RNA in building proteins — is one example of a conceptual model.

It’s important to remember that a model is not reality. We make models based on our current understanding of how the world works. If our understanding of an object or system is flawed, then so is our model of it. This can help identify gaps or errors in our knowledge of something. When a model’s predictions do not align with what we see in the real world, we know the model needs revision.

Models also have limitations. They often simplify systems or processes. A plastic model of a molecule, for example, does not show all of the details of the structure of every atom in the molecule.

Scientists change and adapt models as we learn new things. For example, scientists have revised their model of what an atom looks like several times over the last 200 years. In the early 1800s, English chemist John Dalton described atoms as tiny, solid spheres — like billiard balls. In 1904, British physicist J. J. Thompson discovered protons and electrons and developed a new model of what atoms look like. Today, we use an even newer — and more accurate — model, which is based on strange rules of physics known as quantum mechanics. And in the future, we may have even more accurate models of how atoms work.