Chemical Changes

Chemical changes occur at the atomic level, which means we can't actually see them happening. However, we can use all of our senses and other scientific meters to detect a chemical reaction as it occurs. There are three main signs to look out for when trying to identify a chemical change. They will not always signify the occurrence of a reaction, but they are often linked with chemical changes.
  1. 1. the appearance of a new substance,
  2. 2. irreversible change has occurred
  3. 3. the absorption or release of energy.

Different types of chemical changes have names that describe the processes occurring. Here are some you might know.
  • Decomposition
  • Photosynthesis
  • Oxidation (rusting)
  • Ripening
  • Cooking

Here are some examples.
  • Bread molding--Don't get confused, but there are two chemical changes going on here. Mold, a living organism, is consuming the sugar, water and minerals in the bread. And the bread is decomposing. These changes are irreversible, release smelly gases and produce a small amount of heat.
  • Cake baking--When you bake a cake you are combining several ingredients into a solution, adding energy (heat) and making a new (and delicious) material that cannot be returned into the original ingredients. - great video explaining chemical

5 hand’s on experiments for kids - chemical change (definition and examples)

Understand the difference between physical and chemical change Examples of Physical and chemical changes (see bottom of page) examples of physical and chemical changes. - chemical change vs. physical change site