Simulate Something

If you want to see how a model’s behavior changes over time, you can run a simulation. Simulations can be done using models in real life, but often computers are used to run simulations in the virtual world.

Computer simulations can be very simple, running on a single computer in a matter of seconds. Or they can be very complex, requiring a room full of networked computers working over several days.

Powerful Computers Can Run Complex Simulations

This image shows the visible matter inside a cube representing 248 million light-years. This was the world's most complex scientific simulation of the evolution of the universe ever performed. Michael Norman, a cosmologist from the University of California, San Diego, ran the simulation for more than 130 hours on 512 processors of the Blue Horizon supercomputer.

This simulation required tracking more than a billion particles and performing calculations in more than a billion cells for more than 3 billion years of simulated time.

Image Credit: Michael Norman, Pascal Paschos, UCSD; Robert Harkness, SDSC

Computer Simulations Record Change Over Time

Like individual pages in a flip book, computer simulations preserve snapshots of calculations over time. Each snapshot shows the output of a calculation using a slightly different input value. By putting the snapshots together, the simulation presents an animated view of change over time.

Mathematical Models: the Backbone of Simulations

Mathematical models provide the equations and rules that define a process. Because mathematical models use numerical inputs and outputs, they allow you to see very specifically how a system evolves over time.

When you gather the numerical values as the simulation progresses, you are left with a comprehensive set of data showing values at every step of the process.

Computer simulations are used to model all kinds of systems.
Here are a few examples:
Astrophysicists have created simulations of Earth’s first 500 years of existence.
Video credit: Simone Marchi
Water resource managers use simulations to analyze how changes in water use impact supply.
Image credit: GoldSim
Geographers have used computer simulations to characterize the motion of an avalanche as it flows down a mountain.
Video credit: WSL Institute for Snow and Avalanche Research SLF
In factories, computer simulations can help optimize processes used to manufacture products.
Image credit: Siemens PLM, DELMIA, S-Pridis, ICAM Technologies
Financial analysts use computer simulations to see how changes in the global economy could impact financial assets.
Image credit: Goddard Consulting
Climate scientists simulate Earth’s atmosphere to study how global fossil fuel emissions influence air temperature over time.
Image credit: Met Office Hadley Centre
When threat of a disease epidemic arises, health researchers use computer simulations to track the disease and predict how it might spread.
Video credit: http://www.gleamviz.org/simulator/
Engineers create computer simulations to test traffic flow on proposed roads.
Image credit: The Traffic Group, Inc., Braidwood Associates, SimWalk, City of Salem