NSCI 120 UMGC Natural Science Discussion

Read the item “Models in Science” in this week’s readings. It offers guidance about what kinds of things can be scientific models.  Models generally seek to explain why something happens in nature, unlike a data set that tells what happened in a particular circumstance or experiment.  A scientific model is not

a description of a human process such as a recipe or instruction manual

a scale model of a human construction like a car

a data set or statistical analysis of data

Part 1. Consider a natural phenomenon or natural process that interests you.

Part 2. Create a model of your phenomenon or process. If you have artistic talents, this is the time to use them.

What are the key features of your model?

Your model could be a drawing, a diagram, a scale model, a 3D object, or even a video.

You can use paper, wire, clay, or any other materials. Your model should not just be a picture alone; it needs to explain how something works.

Learning Resource
Models in Science
Scientific models organize data and theories about a process or phenomenon in ways that
lead to greater insight and understanding about the process or phenomenon. Just like
memes on the internet help us communicate a concept or principle, models in science are
forms of communication that go beyond words. However, scientific models must be well
grounded in observations and hypothesis testing.
Models supersede one data set, such as the graph you made for Stage 2 of the
Observation Project. Models culminate from tying together many data sets and
observations and capture the key components of a process or phenomenon. Models are
useful because they help us visualize how data from individual observations and
experiments relate to a larger picture. Experiments and observations are about what
happened, while models help us understand the how and why of nature.
Scientific models can take many forms. Let’s look at a few of them.
Diagrams
A diagram is a simplified drawing that shows the structure or workings of something.
Usually, all its parts are labeled.
Here are a couple of examples:
Diagram of the Earth’s Interior
Diagram of the Orbits of Planets, Asteroids, and Comets
Scale Model
Some things are just too big or too small for us to envision well. A scale model replicates
the important features of something at a much larger or much smaller scale so that we can
interact with it. A globe is an example of a scale model of something very large.
PhotoAlto/Michele Constantini / PhotoAlto Agency RF Collections / Getty Images
In chemistry, we often use models of molecules that look like balls and sticks. The atoms
that make up molecules aren’t like hard balls and atomic bonds are nothing like sticks, but
this sort of representation can give us a notion of the geometry of a molecule and predict
some of its properties.
These are models of S8 and S4, two different forms of Sulfur molecules:
Molecular Art of S
If each green ball represents a sulfur atom, then the diagram on the left represents an
S8 molecule. The molecule on the right shows that one form of elemental phosphorus
exists as a four-atom molecule.
Process Diagrams
A process diagram shows the steps in a process and the order in which they happen. The
process can be linear, with a distinct beginning and end, or circular, a process that resets
to the beginning.
Here are a couple of examples:
Life Cycle of a Medium Mass Star
Rock Cycle Process Diagram
A rock cycle process diagram showing how rocks can be transformed from one type into a
different type.
Scientific models can even be videos that show how a process works. Play the video to
see a simulation that shows how a massive start explodes in supernovas.
0:00 / 0:58
Sloshing Star Goes Supernova
Transcript
Mathematical Models
Scientists often use math to describe how things work. Newton used this equation to
describe the relationship between force and acceleration:
F = ma, where F represents force, m represents mass, and a represents acceleration.
This sort of mathematical model is incredibly useful throughout science because we can
use math and computers to take a simple equation and apply it to a whole range of
situations. The equation F = ma can be used to calculate everything from motions of
planets to the speed of race cars.
Numerical modeling is a process where computer programs are used to solve equations
that are mathematical models. For example, if you wanted to compute the trajectory of a
rocket, you would need to solve F = ma at many different times in the computation. You
would also need equations that describe the forces on the rocket like gravity, atmospheric
drag, and the thrust from the engine. Atmospheric drag depends on both altitude and
speed. The thrust depends on the engine design. The mass of the rocket gets smaller as
the fuel is burned. Starting with the rocket on the ground, you would compute the forces
on the rocket, then predict its position and speed just a fraction of a second later. Then,
you would compute the forces on the rocket based on the new position and speed and
use that to predict the next position and speed. This circular process of calculation repeats
many thousands of times.
Numerical modeling is found throughout the sciences and engineering. It is even used in
fields like economics. Weather predictions are made based on the results of numerical
models that include equations for how we know air masses interact with each other and
the rest of the environment. A different kind of numerical model called finite element
analysis is used to make sure that designs for buildings and machines are sufficiently
sturdy. Numerical models were used to help scientists and policy makers understand
SARS-COV-2.
Chemical equations, such as this equation for the burning of propane, are another sort of
math-based model:
C3H8 + 5O2 → 3CO2 + 4H2O
Professionals in the Field
The movie Hidden Figures shows mathematical modeling in the early
days of NASA, before electronic computers took over the task. NASA
employed a large number of “computers,” (people, many of them African
American women, who performed orbit and trajectory calculations by
hand). Without their work, some of it under extreme time pressure, the
Mercury astronauts would not have returned safely to Earth. There are
even a few scenes in the film where we see NASA just starting to use
computers. Working with computers was actually a female-dominated
profession until the 1980s.
Licenses and Attributions
Figure 1.5.2 (https://opentextbc.ca/physicalgeology2ed/chapter/1-5-fundamentals-ofplate-tectonics/)
from Physical Geology, 2nd Edition by Steven Earle comprises public
domain material in the United States. UMGC has modified this work.
Figure 3.10 Solar System Orbits (https://openstax.org/books/astronomy-2e/pages/3-4orbits-in-the-solar-system)
from Astronomy 2e by Andrew Fraknoi, David Morrison,
Sidney Wolff is available under a Creative Commons Attribution 4.0 International
(https://creativecommons.org/licenses/by/4.0/)
license. © March 11, 2022, OpenStax.
UMGC has modified this work and it is available under the original license. Download for
free at https://openstax.org/books/astronomy-2e/pages/1-introduction
(https://openstax.org/books/astronomy-2e/pages/1-introduction) .
Figure 3.3 Molecular Art of Sg and P4 Molecules
(https://2012books.lardbucket.org/books/beginning-chemistry/s07-atoms-moleculesand-ions.html#ball-ch03_s02_f01)
from Beginning Chemistry is available under a
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Life Cycle of a Medium Mass Star by Lisa Shier comprises public domain material in the
United States. UMGC has modified this work.
3.1 The Rock Cycle (https://opentextbc.ca/geology/chapter/3-1-the-rock-cycle/)
from
Physical Geology by Steven Earle is available under a Creative Commons Attribution 4.0
International (https://creativecommons.org/licenses/by/4.0/)
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Sloshing Star Goes Supernova (https://www.jpl.nasa.gov/videos/sloshing-star-goessupernova)
comprises public domain material from the Jet Propulsion Laboratory,
National Aeronautics and Space Administration. UMGC has modified this work.
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