Of all the science disciplines, teaching chemistry to middle school students is one of my favorites. I enjoy the observable nature or biology and cells, and the real-life connections to physics, but chemistry is unique. Students cannot directly see the materials we spend so much time discussing.
This creates a challenge for us as science teachers. But, it also creates an opportunity to incorporate a critical skill: citing evidence. We have to prove a lot to students in this subject because it is so abstract. Here are some tips for teaching chemistry to middle school students.
How do you address chemistry misconceptions in middle school?
Middle schoolers arrive with a mix of solid background knowledge and stubborn wrong ideas about atoms and reactions. Reinforce the accurate prior knowledge and deliberately challenge the misconceptions with hands-on demonstrations. When students discover the correct answer themselves instead of being told, they remember it and actually make sense of it.
Students may come into your class with a wide variety of background knowledge and incorrect ideas about atoms, molecules, and chemical reactions. Consider using activities that reinforce factual prior knowledge and also purposefully challenging misconceptions.
For example, many students believe that all wood will float while all metal will sink. If you identify this as a misconception your students believe, develop a plan to challenge it. Build a boat made from tinfoil. Add pennies or other weights to it until it sinks.
While not as easy, there are types of wood that are denser than water and will sink. If you have access to one, it would make for a fantastic class demonstration or anchor phenomenon to a density unit.
There is not room to address all the common misconceptions my students have brought with them to my classroom. However, I believe this can show the power of an inquiry-based approach. You can tell students the correct answer to phenomena, and they might remember it. Allow them to discover it for themselves and they are more likely to remember it and make sense of it.
Tip #2: Share Your Own Misconceptions
Chemistry intimidates students, so model that you weren't born knowing it. Sharing what confused you in school builds classroom community and a growth mindset. It shows students you're all in this together, and it makes the frustration they feel a normal part of learning rather than a sign they can't do it.
I like to model to my students that I was not born knowing all the information I teach. Chemistry can be an intimidating topic to students and sharing in their frustration can be helpful.
While learning about atoms, I like to share how I was confused in school when I learned about the nucleus of the atom after learning cell organelles. Why is there a cell nucleus and atomic nucleus? Why are they named the same thing?
Sharing in the struggles of your students can build classroom community in knowing you are all in this together. It can also help build a growth mindset. Don’t be afraid to tell them when you found something confusing in the past.
How should you sequence a middle school chemistry unit?
Chemistry builds concept on concept, so sequence matters. Students can't understand why molecules form until they understand valence electrons and how to find them on the periodic table. Examine your standards, then design a rough outline that builds logically from one idea to the next before you plan any activities.
Chemistry is a very broad topic that builds on information to understand the next concept. For example, its difficult to understand the reason molecules form if you don’t understand valence electrons. They need to know what a valence electron is and how to find them using the Periodic Table.
Examine your standards and think about a progression that will most easily build throughout your unit. Check to see if your standards include those concepts. Then, design a rough outline of the best order to teach them in.
Below, I’ve listed my personal preference for a sequence with some ideas mixed in.
How do you teach the periodic table and atomic structure?
Start with the periodic table because students already have questions about it, giving them a quick win. Move into atomic structure with the PhET atomic structure simulation so students discover how protons, neutrons, and electrons behave. Finish with isotopes and ions, which feel intimidating but build directly on reading periodic table blocks.
I begin with Periodic Table because students usually have questions about it. Explaining some of the basics give them what I like to think of as a “quick win” to pocket. You could explain why some blocks are different colors, identify names they have heard before (like Einsteinium), and why some symbols do not match the name (such as Iron’s symbol being Fe).
Then, I like to explore some places they’ve seen the elements they’ve seen in their lives. A fun activity for this is looking at the ingredients of a cereal box and matching up names with elements. This also pairs nicely with finding the elements on the periodic table using the “period” and “group/family” layout.
Next comes atomic structure. We look at individual element blocks and identify the information it tells us. We discuss the charge and location of protons, neutrons, and electrons. One excellent resource for exploring this using an inquiry approach is the PhET simulation for atomic structure. Students discover the effect of adding or removing each of these particles.
Students will need some practice with the basic calculations of determining the amount of particle in each element. They should also practice making models of atomic structure – either physical, digital, or drawn.
Lastly, introduce isotopes and ions. Students will feel intimidated by those terms but show them its something they already know from their knowledge of how to read periodic table blocks!
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Tip #5: Teaching Compounds and Molecules
Once students understand atoms, move to molecular chemistry. Start with counting atoms in a molecule—subscripts, coefficients, and parentheses—because weak counting skills wreck equation balancing later. Then teach ionic and covalent bonding, using a demonstration like vinegar and baking soda so students understand why bonds form.
After understanding the nature of atoms, I move to molecular chemistry. I start with counting the number atoms in a molecule (subscripts, coefficients, and parentheses). I really put a focus on this because it will cause a lot of frustration later when balancing equations. That skill is difficult enough without having to reteach counting atoms in the middle of it.
Next up – explaining ionic and covalent bonding. This is a fairly simple concept to teach but students need to have an understanding of why these bonds exist. I like to show a demonstration of a chemical reaction (such as vinegar and baking soda) and compare it to the chemical reaction.
How do you teach balancing chemical equations to middle schoolers?
Take it slowly and use many strategies. Start by identifying whether an equation is balanced, listing atoms on each side of the yield arrow. The PhET balancing equations simulation and physical modeling with blocks or marshmallows both help. Then practice—one coefficient, then two, then combustion reactions as a challenge.
The demonstration from Tip#5 also serves as a good lead-in to balancing chemical equations. This skill takes time but is one of my favorites to teach. This is one of those “lightbulb” moments when students see how something works and can master a skill they thought impossible. Take this one slowly and use many different strategies for teaching it.
PhET has a fantastic simulation for this as well. This simulation makes the lightbulb turn on for many of my students. You can also do a physical modeling activity in which you represent atoms with blocks, marshmallows, or some other item. Finally, just practice, practice, practice. Try to choose easy equations first and move up in difficultly.
I start this skill with simply identifying if an equation is balanced or not. I teach them to identify the reactants and products. I draw a line down the middle of the yield arrow to separate the reactant and product sides. Then, I list each type of atom on both sides. Finally, I teach students to use what they learned in the counting atoms unit to determine if it is balanced.
Next, practice balancing simple equations that only require changing one coefficient. Then, move into equations that require changing two coefficients. For an extra challenge, balance combustion reactions.
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Tip #7: Physical and Chemical Changes
After balancing equations, teach identifying physical and chemical changes—a natural fit for a claim, evidence, and reasoning approach. Students make a claim about the type of change, cite evidence like color change or gas evolution, and explain their reasoning. It's also a good place to introduce endothermic and exothermic reactions.
After mastering the important skill of balancing equations, I move to identifying physical and chemical changes. This part of the unit lends itself well to a claim, evidence, and reasoning approach. Students will make a claim about the type of change. Then, they cite evidence to support their claim. Lastly, they explain the reasoning of how their evidence supports the claim. We discuss evidence of changes such as color changes, evolution of gas, change in size, and many others.
This is also a good place to discuss endothermic and exothermic reactions. Again, require students to cite evidence to explain why a chemical reaction is endothermic or exothermic.
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Chemistry is a complex topic. It is especially difficult for middle school students to understand the largely abstract phenomena occurring at levels which they cannot see. However, it is a critical subject that can set them up for success in high school. The skills they learn in your classroom will benefit them for years to come as they progress through their remaining science courses.