Chemical reactions are processes that involve the rearranging of atoms to make new substances. People often imagine that they only occur in a test tube in a science laboratory, but in reality, chemical reactions happen everywhere around us. For example, our bodies use them to function, and even some types of weather are chemical reactions. The following activities are aimed to help introduce students to chemical reactions and help them understand exactly what they are!
Throughout history, scientists have been fascinated by the way that some substances can transform into other substances. During the early years of science, many scientists were also engaged in the practice of alchemy, which included attempting to turn base metals, like lead, into gold.
The total number of atoms and the total mass of the atoms is conserved during a chemical reaction. It was French chemist Antoine Lavoisier who showed that the mass of the reactants in a reaction is equal to the mass of the products. This means that no atoms are created or destroyed in a chemical reaction. However, bonds between atoms are broken, the atoms rearrange, and then new bonds are made. When using Storyboard That to model chemical reactions, you’ll want to use the “equipment” and “symbol” assets listed under “Science.”
Word equations provide the names of each of the reactants and products. For example methane + oxygen → carbon dioxide + water . In this equation, methane and oxygen are the reactants and carbon dioxide and water are the products. These equations are helpful when looking only to understand exactly what is produced in a reaction.
Another way of describing chemical reactions is by using symbol equations. Symbol equations not only allow us to know the reactants and products involved in the reaction, they also let us know the chemical composition of the substances involved. For example, the word equation for the combustion of hydrogen gas in air is hydrogen + oxygen → water. The symbol equation is H2 + O2 → H2O. There’s only one issue: the equation is not balanced. On the right hand side there are 2 hydrogen atoms and 2 oxygen atoms. On the left hand side, there are two hydrogen atoms and one oxygen. We know that atoms are not created or destroyed in chemical reactions. In order to rectify this, we need to balance the equation using coefficients. 2H2 + O2 → 2H2O is a balanced equation. Now we have four hydrogen atoms and two oxygen atoms on the right hand side. The left hand side remains the same.
From a balanced symbol equation, students can create stick and ball models on Storyboard That. This helps students understand how bonds are broken and how the atoms are rearranged during a chemical reaction. It also allows them to visualize symbol equations in a more easily digestible manner.
Students can often find it difficult to differentiate between physical and chemical reactions. Physical changes do no create new substances. The old substance is the same as the new substance, and the old substance can easily be recovered. Melting and dissolving are two examples of physical reactions. Those substances can be solidified again or recovered via evaporation. Chemical changes occur during chemical reactions, and this means new substances are produced.
There are several different indicators that a chemical reaction has occurred. Often, the products of a chemical reaction can be very different to the reactants.
Indicators that a chemical reaction has occurred:
This is a great opportunity to show your students a range of different and exciting chemical reactions, some of which the students will be able to complete themselves. Others are better suited to teacher demonstrations. As with any practical work, make sure they are properly risk-assessed and the students are made aware of safe practices.
The Next Generation Science Standards push the importance of getting students to develop and use models to understand phenomena. In the real world, scientists will make models to aid their understanding of a system or part of a system. Models are used in science to make predictions and communicate ideas or data to other people. There are activities here that focus on honing the skill of creating models. Students will easily be able to create their own models of atoms to describe the arrangement of atoms in chemical reactions. This gives you a great opportunity to discuss the limitations of using models, giving students the opportunity to evaluate and refine them.
Plan a simple experiment Choose an age-appropriate chemical reaction, such as baking soda and vinegar, that clearly shows a change like fizzing or color shift. Demonstrate safety procedures before starting.
Describe what’s happening as you mix the ingredients. Use clear language to point out signs of a chemical change, such as gas production or temperature shift. Encourage students to make observations throughout.
Ask students to write or draw what they observe during the demonstration. Let them note changes in appearance, smell, and temperature. Support different learning styles by allowing both text and visuals.
Prompt students to share their findings and relate them to the definition of chemical reactions. Highlight how the demonstration shows new substance formation and reinforces the lesson’s main ideas.
Invite students to think about reactions outside the classroom, like rusting or cooking. Help them see chemistry in daily life and spark curiosity for future learning.
A chemical reaction is a process where atoms are rearranged to form new substances. This can be seen in everyday life, like baking a cake or rust forming on metal.
You can identify a chemical reaction by signs such as gas production, new odors, temperature changes, color change, or the formation of a precipitate.
Chemical changes create new substances, while physical changes do not. For example, melting ice is physical, but burning wood is chemical.
Try activities like modeling reactions with stick and ball models, balancing symbol equations, and creating spider diagrams of everyday chemical reactions to engage students.
To balance a chemical equation, adjust the coefficients so the number of each type of atom is equal on both sides. For example, 2H2 + O2 → 2H2O is balanced.