Model Chemical Elements And Molecules With Bricks

Model Chemical Elements And Molecules With Bricks

Grade Level

3 - 8


15 min - 1 hr



Take a look at these two pictures of mountains. What do you notice? How are the mountains the same? How are they different?

Two pictures of rock formations. On the left, red and stratified desert rock formations are shown. On the right, the rock formation is gray and solid.
Compare the way the rock formations look. Credit: Sandy Roberts, using images from Canva

You may have noticed that the rock formations are very different colors. The rock formations on the left are from Red Rock State Park in Texas, and on the right is El Capitan Mountain in Yosemite National Park in California. The colors are so different thanks to one crucial element: oxygen.

What Are Elements And Compounds?

Elements are the chemical building blocks of matter. Everything in the universe that takes up space is made of elements. There are 92 elements found in nature and another 20 or so that scientists created in a lab.

When elements combine, they form compounds. For example, water is made of two atoms of the element hydrogen, and one atom of the element oxygen. That’s why it’s often denoted as H2O. A chemical reaction is a process in which two or more substances—elements or compounds—are converted into a new substance. When atoms combine, we call that a molecule.

What does this have to do with the mountains in the picture? The rock on the left contains a lot of iron. The iron reacts with oxygen in the air, turning the rocks red. This reaction is called oxidation, the same process that rusts metal.

A green pole with an old chain. When the paint has worn away, the metal has turned red.
Do you see the spots where the green paint has worn away? The exposed iron went through an oxidation reaction. In other words, it rusted. Credit: Shutterstock

Build Your Own Compounds

A great way to understand chemistry is to use models representing atoms and molecules to see how they fit together. You will use plastic construction or building bricks, like LEGO bricks, as atoms of different elements. These models are based on the work of MIT Edgerton Center and LEGO. If you enjoy this activity, there are many more lessons you can try.


  • Several 1×2 building bricks in white for hydrogen. (It’s the smallest atom.)
  • Several 2×4 building bricks in four different colors
    Suggested colors:
    – black: carbon
    – red: oxygen
    – blue: nitrogen
    – orange: phosphorous

Safety note: Bricks present a choking hazard for young children. Please keep bricks out of reach of children under three years of age.

If you don’t have bricks of the same size or color mentioned above, substitute with what you have. If you don’t have any building bricks at all, try using clay or gumdrops with toothpicks instead.

For this activity, you’re going to focus on just five elements that were incredibly important to shaping the environment on our planet: carbon, hydrogen, oxygen, nitrogen, and phosphorus. They occur in nearly every organism on Earth.

Modeling The Components In Air

An atom is the smallest possible piece of an element. When atoms bond, they make molecules. Many molecules form new compounds when different elements bond together. However, some atoms combine into elemental molecules where two of the same elements combine. Hydrogen, oxygen, and nitrogen form elemental molecules.

Let’s start by making some elemental molecules:

  1. Select two blue bricks.
  2. Attach the bricks, offsetting them so that the top brick overhangs the bottom brick.
  3. Make seven more nitrogen molecules.
  4. Select two red bricks and put them together in the same way you did with the blue bricks.
  5. Repeat to make a second oxygen molecule.
On the left, two 2x4 blue plastic construction bricks are attached in an offset manner. On the right, two red bricks are in the same formation.
Connect two nitrogen bricks to make a nitrogen molecule. Repeat with red oxygen bricks. Photo credit: Sandy Roberts, based on MIT Edgerton models

You should now have ten molecules: eight blue nitrogen and two red oxygen. Congrats! You’ve made air, which is almost 80% nitrogen and 20% oxygen.

A group of eight blue nitrogen brick models and two red oxygen brick models.
Can you make the nitrogen and oxygen models to represent the major components of air? Photo credit: Sandy Roberts, based on MIT Edgerton models

Since air also contains a tiny bit of water vapor, make a water molecule too.

  1. Select one red brick and two white bricks.
  2. Holding the red brick lengthwise with the studs facing upward, attach a white brick to either end of the red brick.
A red 2x4 plastic brick with two white 1x2 bricks attached in a U formation.
Attach two white hydrogen bricks to your red oxygen brick to make a water molecule. Credit: Sandy Roberts, based on MIT Edgerton models

Great! Your air needs just one more thing: carbon dioxide. Carbon dioxide is a waste product that living organisms—like you—produce when they make energy. Plants take in carbon dioxide and, through photosynthesis, make oxygen. Let’s make a carbon dioxide molecule.

  1. Select one black brick and two red bricks.
  2. Align the two red bricks next to each other lengthwise with the studs facing upward.
  3. Center the black brick over the place where the two red bricks meet and attach them.
Two red 2x4 plastic bricks with on black 2x4 brick attached to the top, bridging the red bricks.
Attach one black carbon brick to two red oxygen bricks to make a carbon dioxide molecule. Credit: Sandy Roberts, based on MIT Edgerton models

Together, these molecules make the air we breathe.

Creating A Molecule Group With Phosphorus

Phosphorus is an element found in rocks and soil, but not air. It’s in molecules like DNA and RNA, your genetic blueprints, and ATP, the chemical energy you use to fuel your body. Alone, phosphorus is very reactive, even explosive. So, it bonds to other elements to form a more stable phosphate group. Let’s build it!

  1. Pick out four red bricks and one orange brick.
  2. Align the two red bricks next to each other lengthwise, with the studs facing upward.
  3. Center the orange brick over the place where the two red bricks meet and attach them.
  4. Attach the remaining two red bricks onto the open studs of the orange brick. The red bricks should form a cross or lowercase “t” shape.
Four red 2x4 bricks are arranged in a cross form, with an orange 2x4 brick placed on top of the cross to connect all the red bricks.
Attach four red oxygen bricks to an orange phosphorous brick to make a phosphate group. Photo credit: Sandy Roberts, based on MIT Edgerton models

Molecule Mysteries

Now that you’ve built some model molecules, try the challenge below to test your knowledge and skills.

In the picture below, there are several different molecules: hydrogen peroxide, propane, carbon monoxide, carbonic acid, acetic acid (vinegar), and nitrous oxide. Which is which? Do the names of the molecules offer any clues?

There are six brick molecules pictured. Top left: two red 2x4 bricks with two white 1x2 bricks; top middle: 3 red 2x4 bricks connected by a black 2x4 brick with two 1x2 white bricks; top right: two black 2x4 bricks connected in an offset manner with two red 2x4 bricks attached on the right end and four 1x2 white bricks attached. Bottom left: one red 2x4 brick and one black 2x4 brick connected in an offset manner; bottom middle: three black 2x4 bricks connected in an offset manner to look like stairs with 6 1x2 white bricks at each end on top and bottom; bottom right: two red 2x4 bricks connected by a blue 2x4 brick on top.
What molecules do you think these brick models represent? Check your answers here. Photo credit: Sandy Roberts, based on MIT Edgerton models

As you think about the models you have made, ask yourself:

  • How are the molecules you made the same, and how are they different? What may be the reasons for those similarities and differences?
  • Are there limits to how many atom bricks you can attach to a single brick? What are the limitations? Would such limitations exist in nature with chemical molecules?
  • What other molecules can you make using these five elements? (You may need to do some research. See the suggestions at the end of this resource.)
Related Segment

How Five Elements Define Life On Earth

Elements Shaped Our Planet

In his book, Elemental: How Five Elements Changed Earth’s Past and Will Shape Our Future, author Stephen Porder argues that these five elements—your building blocks—are “life’s formula.” Ninety-nine percent of our cells are made of carbon, hydrogen, and oxygen. Meanwhile, 80% of the air we breathe is made of nitrogen. And phosphorous? It’s the key to almost every biological molecule used by every organism on Earth. Over time, the availability of these elements forced organisms to adapt to changes in the climate and environment. Even now, these elements shape life on the planet as fundamental building blocks of your cells, the soil, the air, water, and even the fossil fuels we use to make energy.

“[O]ur living planet is not just a living planet because it houses life, but because it’s shaped by life. And this interaction between the living and unliving world is really what determines the characteristics both of our planet and the organisms that live upon it.” – Stephen Porder

Keep Learning About Elements And Compounds

Want to learn more about atoms, molecules, elements, and compounds? Here are some things to try:

Next-Generation Science Standards

This resource works toward the following performance expectations:

Lesson by Sandy Roberts
Copyediting by Lois Parshley
Digital Production by Sandy Roberts

On the left black silhouette of a drop oof water splashing into a larger body of water. To the right there are the words MIT Edgerton Center.

The molecular modeling system described in this set of activities was created by Kathleen M. Vandiver, and additional materials and examples can be found on MIT Edgerton Center website.

Meet the Writer

About Sandy Roberts

Sandy Roberts is Science Friday’s Education Program Manager, where she creates learning resources and experiences to advance STEM equity in all learning environments. Lately, she’s been playing with origami circuits and trying to perfect a gluten-free sourdough recipe.

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