Posted by Christy Williams on July 26th, 2016
Chemical reactions are among the many science related concepts that adult students must be familiar with in preparation for the high school equivalency (HSE) exam. A chemical reaction changes a substance into a new one with a different chemical identity. When two or molecules interact and change the molecules, a reaction results. The substances that react are called reactants; the result is called a product. Chemical reactions change the physical and chemical properties of molecules. The changes produced by chemical reactions are permanent.
As instructors, communicating the idea of chemical reactions can happen multiple ways for your adult learners. Students can gain a stronger understanding of chemical reactions through lecture, discussion, demonstration and hands-on activities.
Chemical Reactions in Daily Life
Identifying chemical reactions in daily life is one way to teach this concept to adult learners. Discuss the various examples and what causes them to be categorized as chemical reactions rather than just physical. Examples of chemical reaction in daily life are:
- Baking – Ingredients cannot be returned to their normal state once they have been baked.
- Combustion – Examples include building fires, burning candles, and lighting grills.
- Digestion – Enzymes and stomach acids break down the food being eaten.
- Photosynthesis – Photosynthesis is a reaction to make food for plants.
- Production of fermented products – Ideas of fermented products include cheese, yogurt, bread, wine, beer and many other common items.
- Rust – Rust and tarnishing of silver are commonly observed chemical reactions.
Demonstrations and Hands-On Activities
Demonstrations and hands-on activities help students understand the chemical reaction process. Hands-on activities reiterate the concept by allowing students to create the changes themselves. Simple activities to try include:
- Baking – Have students bring in a favorite simple, baking recipe. Identify the reactants which will interact and the resulting product. Discuss what evidence supports baking as a chemical reaction.
- Chemical or Physical Reaction – Demonstrate the differences between physical and chemical reactions with illustrations using ice and eggs. Discuss: With the ice melting into liquid, has a physical or chemical reaction occurred? How do you know? Boil or fry an egg. Discuss what classifies the product as a physical or chemical reaction. Find other examples to sort.
- Naked Egg – Chicken egg shells are made primarily of calcium carbonate. A chemical reaction to dissolve the shell is created by soaking the egg in vinegar. The result is a “naked egg”.
Discussion surrounding chemical reactions in daily life and hands on activities are effective ways to teach chemical reactions to adult learners. Similar to a reaction, the combination of direct instruction, discussion and demonstrations yields a well-rounded understanding for learners. It is important for students to remember that chemical reactions completely change both the physical and the internal composition of an object permanently. This will help them more easily identify a chemical reaction.