Imagine spending years building a skyscraper, forty floors high. Finally, the last window is set into place and the final piece of tile installed. You plan a grand opening ceremony to unveil your creation to the eager public, but before the big day arrives, a storm blows in. High winds course through the city, and your skyscraper begins to sway in the ever-stronger winds. Finally, incredibly, it …
Scale models are physical models of an object or system. We usually build them to represent something that is much larger or much smaller than they are. Scale models are proportional to the original object. When scaling an object to a smaller size, we scale every part of the object by the same ratio. If a dinosaur is being reduced to 1/8 its original size for a museum display, his head, hi…
Some models, such as maps and charts, are two-dimensional representations of something. We call these graphical models. Maps are especially helpful when traveling in an unfamiliar city. Graphical models like this map are often used in schools to help students learn about the world. Many maps include symbols that represent different things, such as roads, bridges, streams, and c…
Another kind of model is useful in explaining concepts, or ideas. A conceptual model can illustrate the water cycle, where evaporation and transpiration lead to the formation of clouds and then to precipitation in the form of rain, sleet, or snow. Conceptual models can be diagrams. A food web is an example of a concept drawn as a flow chart. It illustrates the interconnected food chains in a comm…
A mathematical model is an equation that illustrates the way a process works. We can use a mathematical model to calculate how a country's population will grow over time. Engineering, statistics, and computer science are among the many fields that employ mathematical models in their work. Engineering students put their ideas into practice. The study of physics relies on mathematical…
A computer model, or simulation, is one type of mathematical model. Computer simulations are used in many fields of science, including physics, chemistry, biology, and economics, as well as in technology, entertainment, and business. We use computer models to predict where air pollutants in the atmosphere will go. In the event of a chlorine spill, for example, computer models can tell emergency p…
Models of the solar system show the positions of the planets and their moons as they orbit the Sun. While these models are useful in comparing the sizes of the planets and moons, it is difficult to build them to scale. Distances between planets are huge compared to the size of the planets. Think of the globe in your classroom. Most classroom globes are 16 inches (41 centimeters) in diameter. If …
A stalk of celery can model the process of capillary action, by which plants conduct water from their roots to their leaves. Place a freshly cut stalk of celery in a glass of water that has been tinted with red food coloring. After a few hours, you will be able to see the red liquid in the veins of the plant. You can trace the path of the water as it makes its way from the stem to the leaves of t…
Plant and animal cells are too small to see without a microscope, but we can make a model of a cell. One fun idea is to use different foods for the different structures of the cell. Gelatin can act as the cytoplasm. If you pour gelatin into a container and refrigerate it until it is almost set (about an hour), it will be the perfect medium to hold all the cell components in place. You can use di…
computer model (kuhm-PYOO-tur MOD-uhl): a computer program that is used to model something conceptual model (kuhn-SEP-shu-uhl MOD-uhl): a written or illustrated explanation of how something works diameter (dye-AM-uh-tur): a line segment that passes through the center of a circle and has endpoints on the circle dimensions (duh-MEN-shuhnz): the length, width, and height of an object graphical model…