Atoms and Molecules

Teaching abstract concepts in science is never easy, and helping elementary and middle school students understand the concepts of atoms, molecules, and elements can be especially difficult. However, if you are able to utilize activities that make these ideas more hands on, students will have a much better basis for understanding higher level concepts in high school science courses.

An atom is the smallest part of an element that still has all the properties of that element.  Elements make up everything on our planet, and scientists organize them by properties on a chart called the Periodic Table.  Molecules are made up of combinations of atoms. Depending on how the atoms are combined, they can have entirely different effects. For example, carbon dioxide is made up of one atom of carbon and two atoms of oxygen. We breathe out this gas every time we exhale, and plants use it in their own respiration. However, if we remove just one atom of oxygen, we create an entirely new molecule called carbon monoxide. A gas which is poisonous to humans! 

You can make these ideas more real for students by conducting kinesthetic activities. Start with a simple molecule like water, which has a formula of H₂O. Students can look at the Periodic Table and see that “H” is the symbol for hydrogen, while “O” is the symbol for oxygen. The number after each element shows how many atoms of that element are found in the molecule (if there is no number below the element, there is just one atom of that molecule). Therefore, there are two hydrogen atoms and one oxygen atom found in water.

In front of the class, ask three students to create a molecule of water. Designate one student as “oxygen” and ask her to link arms with a “hydrogen” student (one on each side). This group of three is now a water molecule!  Challenge the entire class to create other common molecules by finding the appropriate numbers of partners and designating each one as the proper elements.  Some examples are NaCl (sodium chloride, or table salt), CO₂ (carbon dioxide), NH₃ (ammonia), O₃ (ozone), NaHCO₃ (sodium bicarbonate, or baking soda), and H₂SO₄ (sulfuric acid, or battery acid).  For added fun, you can have students form water molecules and demonstrate how the molecules move in solid, liquid, and gas form. Water molecules in a solid (ice) are packed closely together, while the molecules in liquid water are further apart and move slowly.  Gas molecules (water vapor) will spread throughout the entire room and move quickly. This is a great way to get every student involved.

For other hands on ways to teach the concepts of atoms, molecules, and elements, try the following lesson plans.

Atom and Molecule Lesson Plans:

The Atoms Family Album

In this worksheet students conduct an activity in which they simulate the behavior of an atom. Students also learn about the structure of atoms, draw a picture of an atom, and sing a song about atoms.

Marshmallow Molecules

Students create common molecules in this activity using such things as marshmallows and toothpicks. They also review chemical formulas.

Building Molecules From Atoms

In this activity students discuss how atoms form molecules. Students find out how different atoms react to form molecules, and build models to show how this happens.

Battling for Oxygen

Using gumdrops and toothpicks students make oxygen and ozone molecules. They use these models to depict global ozone levels. Students collect date and graph information about ozone levels in the past 50 years.