Teaching chemical reactions in middle school science can be tricky because you provide the foundation for lessons that will be taught in high school. Your students most likely don’t have a lot of background knowledge on this topic, so you will have to find creative connections.
For example, all of your students have some background knowledge about baking a cake. They know that ingredients are combined and then heated to make something new. This is a great place to start talking about chemical reactions. The ingredients for the cake are the reactants in a chemical reaction. Heating the ingredients provides the energy needed to start the chemical reaction that breaks the bonds of the reactants and reforms new bonds to make the product, in this case, a cake.
The Right Background Knowledge
To understand chemical reactions, your students are going to have to know about chemical bonding. To know about chemical bonding, they will have to know about atoms and valence electrons. If your students have this background knowledge, they are ready to learn the definition of chemical reactions and the types of chemical reactions.
Chemical Changes vs Physical Changes
One of the first things you need your students to understand is the difference between a chemical change and a physical change. The most obvious difference between the two is that most chemical changes are harder to reverse than physical changes. Also, chemical reactions change the atomic structure of molecules, and physical changes do not. This is the perfect time for a sorting activity! You can list several changes that can happen to substances and have students sort them to show if they are chemical changes or physical changes.
The Vocabulary of Chemical Reactions
You will also want to be sure students know the vocabulary of chemical reactions. For example, they will need to know about reactants and products. I love using word walls in middle school science because students can access the information they need immediately. You can see all of the vocabulary words in my chemical reactions world wall set by clicking the picture below.
Students will also need to be able to read and write chemical equations. This includes knowing which atomic symbols to use to represent each element and the meaning of subscripts and coefficients. Students can also learn about balancing chemical equations. This simple activity will give them tons of confidence when they revisit the topic in high school.
Types of Chemical Reactions
There are five main types of chemical reactions. Synthesis reactions combine two or more simpler substances to form a compound. Decomposition reactions break a compound into two or more simpler substances. Combustion reactions combine a substance and oxygen to release heat, carbon dioxide, and water. In single displacement reactions, one element replaces another element in a compound, and in double displacement reactions, two compounds exchange elements. Reading chemical equations is key to recognizing each type of chemical reaction.
The Law of Conservation of Mass
Hopefully, your students already learned about the law of conservation of mass, but if they haven’t, this is the time to introduce it! If they have learned about it, take this opportunity for a review! Studying chemical reactions is the perfect time to see that the number of atoms and the amount of mass stay the same throughout a reaction. For a long time, scientists thought reactions could cause an increase or decrease in the amount of mass of the reactants. In fact, it looks like this happens in some reactions, but Antoine Lavoisier proved that both the number of atoms and the amount of mass stay the same throughout a chemical reaction.
How to Teach Chemical Reactions
If you need a little support, you need my reading passage and activities set! You get information pages and activities that will teach your middle school students everything they need to know about chemical reactions. You can print the pages or share them with your students on Google Classroom.
If you want me to take over planning the entire unit, then I can do that too! I have everything you need, and it is organized to make your planning as simple as sharing on Google Classroom and making copies! You get flashcards, the vocabulary word wall, all of the reading passages and activities, exit tickets, and a test with a study guide. Seriously, I have done everything for you! I even include a link to a video you can use to get your students excited about learning about chemical reactions! Instead of spending your time planning your lessons, you can focus on supporting your students.
Are You Teaching Another Science Topic?
I am working on creating more science units so that every science teacher can get exactly what he or she needs for her students. You can also read about how I use brain science to teach other science topics on my blog. Click the pictures below to learn more.