Lesson 5: Chemical Energy

Getting Started

Today you will learn about chemical bonds — attractive forces between atoms that keep them together in groups. They are not physically attached, but a force holds or bonds them together. Because of these bonds between atoms, these substances have potential energy in the form of chemical energy. When a chemical reaction occurs, one or more of the chemicals becomes a new and different substance. During a chemical reaction, the bonds between atoms are broken or created.

Stuff You Need

  • Let's Explore Energy by Moving Beyond the Page
  • baking soda
  • citric acid (kit)
  • clear glass cup
  • colored pencils or markers
  • glass jar (kit)
  • graduated cylinder (kit)
  • large marshmallows
  • measuring spoons
  • periodic table of elements (kit)
  • plastic spoon
  • scissors
  • small bowl
  • small, colored marshmallows
  • steel wool (kit)
  • thermometer (kit)
  • uncooked spaghetti noodles
  • vinegar

Ideas to Think About

  • How are matter and energy related?
  • How do substances interact and change into new substances?

Things to Know

  • An atom is the smallest component of an element and is made up of protons, neutrons, and electrons.
  • An element is a substance made up of one type of atom.
  • A molecule is formed when two or more atoms are bonded chemically.
  • A compound is a molecule made up of two or more elements.
  • An exothermic reaction is a chemical reaction that releases energy in the form of heat and/or light.
  • In an endothermic reaction, energy is taken in and is transformed into chemical bond energy.


  • Recognize that all matter is made of small particles called atoms, too small to see with the naked eye. (S)
  • Distinguish between atom, element, molecule, and compound. (S)
  • Understand that endothermic reactions absorb energy and exothermic reactions give off energy. (S)

Introducing the Lesson

Explain to your child that today he will observe chemical reactions. This will help him to understand how energy causes change. Ask him what he knows about elements, atoms, and molecules.
Reading and Questions
Materials: Let's Explore Energy by Moving Beyond the Page
Read about chemical energy on pages 15-20 of the Let's Explore Energy booklet and then answer these questions.
  1. What makes an atom of one element different than an atom of another element?
    They have a different number of protons in their nucleus.
  2. In a chemical reaction, what are reactants? What are products?
    Reactants are the substances that are being combined and are reacting with each other. Products are the substances that result from the reaction. (In an exothermic reaction, energy is also considered a product.)
  3. Explain the role of energy in a chemical reaction.
    Energy is used at the beginning of a reaction to break apart the bonds between atoms. Then, as products are formed, energy is given off when atoms recombine and form new bonds.