For some students, picking out periodic trends on the table feels more like a witch stirring a cauldron of all the elements, reaching in and grabbing a random one out. Double, double toil and trouble; Fire burn and cauldron bubble. Oh, and boron has lower first ionization energy than beryllium. First ionization energy (IE1) can be a tricky concept for some grade-level chemistry students to understand. There is the general trend, but also the exceptions to the trend. Predi

Sometimes it’s the little things that make a difference. And this is one of those little things! There are often chemistry labs that require a number of different reactants that should be used in a particular order. In my lab, because I have relatively small class size, I often mix up reactants in a couple of beakers or flasks and then the lab groups will pass them from one station to the next. And then the questions start coming. Mr. Koch, where is the … As they expect me

My light and electrons chapter used to feel like I was an old man sitting on a bench telling a wandering story to the squirrels that had about 12 “and then” statements in the middle. Valence electrons. And then the shape of the periodic table. And then Aufbau diagrams. And then quantum numbers. And then Lewis dot structures. And then flame tests… All of these concepts pull directly or indirectly from electron configurations. This year in my grade-level and honors chemis

I may be the last chemistry teacher on Earth to realize this about chemical equilibrium. The reaction quotient (Q) and Le Chatelier’s Principle are just two different sides of the same coin. And in fact, Keq, Q, ICE boxes and Le Chatelier’s Principle are all on the same coin too. This is the first time that I have taught them essentially as a single concept. And I have to admit, student understanding about all of it has improved significantly. Here was my progression thro

Pacing is important. If the students are lollygagging, you won’t cover what you need to. If you are speeding through content faster than they can handle, you are setting them up for failure. Whether it’s in a lab period or the whole year, having the correct pacing sets the students up for success. Here are some tips about pacing to help you maximize your time and effort. Use the finger gauge In yesterday’s lab, my class had to work through 9 different compounds in a flame

I sounded like Charlie Brown’s teacher to them. I was explaining a lab for Beer’s Law and how to calculate the equilibrium constant for the creation of FeSCN2+. It is a multiple phase lab. First we collect classroom data with known concentrations of the red ion to create a concentration vs absorption graph. Then students do their own experiment and utilize the Beer’s Law graph to determine concentrations at equilibrium. I found myself saying “and don’t forget” repeatedly.

Getting kids to interact with each other in a positive way at the same time interacting with the content sounds like a big challenge. You can often get one or the other. Getting both at the same time is how you change the culture of your classroom. Yesterday I stumbled upon a really quick method that led to kids talking, engaging with the content and then having to defend their thinking. I called it the Thumb-o-meter. Here is how I did it. We are studying the history of

The difference between mass, weight, and density can be blurry in a student’s mind. In fact, to the same question asked in class, different students will give all three of those terms. Here is a funny little video clip that I use to distinguish those terms. Added bonus, it stars Weird Al Yancovic. https://www.youtube.com/watch?v=XmLR235VQes Distinguish Mass and Weight Start the clip at 2:30. Let it run until 3:30 when he is sprinkling the sand. Then I ask the question, “W

We hate being wrong. Some of us more than others. But we all hate being wrong. It was 1988. I was given a test to see if I qualified for the TAG program at school. I knew it was important that I do my best. The psychologist was flashing cards in front of me, and I was to name them as fast as possible. And then up came THE picture. It was a girl in a tutu with her arms gracefully arcing above her head. I knew what it was. I just couldn’t remember the word. My mind sp

I am going to poke the hornet’s nest. Hear me out. You should teach significant figures at the beginning of chemistry. There. I said it. You should teach sig figs. There are so many differing opinions on this topic. Just read the comments of any sig fig post. Some are adamant that industry hasn’t used them for years. Others say every measurement in their research lab must use them. Teachers will say their kids will miss the point forever. Others say they are prepar

He was shocked. I had just told a coworker that I was going to be doing a lab in both chemistry and AP chemistry during the first week of school. The reason for his surprise is that I told him that I wouldn’t be spending a whole week on classroom rules, procedures, get to know you questions, intro games, etc. No. In my class, we start as soon as possible. Here are some alternative ways to start your school year besides pairing up and playing two truths and a lie. Spread

My nephew asked a question this week as we were backpacking. “Can we make a game out of these?” “These” were sweaty Skittles that had started to donate their color to his palms and stick together. Of course we can. We can make a game out of anything. For the next two hours we played games using only sweaty Skittles as we sat on our rock by the lake until dark and then we moved the game into the tent. His engagement with these games was off the charts. If a 12-year old ca

Quick Answer In the final days before the AP test, narrow your review by (1) using one-line concept summaries to identify weak spots and (2) drilling “trigger words” that signal correct reasoning to graders. These two strategies keep review focused, efficient, and aligned to how AP exams are scored. We are down to the final panic days of review for the AP test. Deciding what to review can be challenging since there is such a huge amount of content. This year, I used two diffe

It’s AP review season! This year I added a review activity that really helped students remember key labs. It took one 90-minute block and was high-impact with minimal prep. Here is how I did it. Step 1: Assign Students a Previous Lab Each student was assigned one of the labs that we completed during the year. Fortunately, my classes keep a digital lab book, so they could quickly access methods, data, and calculations. Each student was given an 8.5”x11” piece of paper to make

Quick Answer Electrochemistry clicks when students can see it, not just calculate it. Using simple, memorable images—OIL RIG for redox, Red Cat / An Ox for electrode identity, and visual cues for mass changes and cell potential—gives students anchors they can recall during problem-solving. Instead of memorizing disconnected rules, they reconstruct the system from the image: where electrons flow, which electrode gains mass, and how to calculate cell potential. These visuals tu

Quick Answer: How to Make the Heating Curve of Water Engaging Quick Answer If you want to make the heating curve of water engaging, pair the math with a live heating demo and force students to predict, justify, and bet on outcomes. This turns a passive graph into an active reasoning task—students connect temperature, energy, and phase changes in real time, which makes the concept stick. That’s about as much fun as watching water boil. Actually, that can be pretty fun—but onl

Quick Answer: The Ping Pong Review is a fast, partner-based chemistry review strategy where students alternate steps on a problem, creating built-in feedback and deeper engagement. Your students need review. But if you are like most high school chemistry teachers, the word “review” makes your skin crawl. You are forced to decide whether review is worth the minutes in your class. Is it actually helping students master chemistry concepts—or just filling time? I discovered a

Have you ever been here? You explain your lab perfectly. The students are told the process, the calculations, the safety concerns. You have given an Oscar-worthy performance. And within 2 minutes of the start of the lab, a student asks, “Where do I get the grams of sodium hydroxide?” What! Where else would you get the grams of sodium hydroxide? Are you serious? Didn’t you listen to my explanation? And the answer is they did listen to your instructions, but they didn’t

Why Students Struggle with Limiting Reagents Even with our best efforts, it can be hard for some students to comprehend what a limiting reagent really does in a reaction. Many high school chemistry students struggle to understand limiting reagents in stoichiometry because they cannot visualize which reactant actually “runs out” first. In between my first and second Alka-Seltzer chemistry lab yesterday, I introduced a very simple demo that really helped. Even though I had

Many chemistry teachers introduce the mole right before stoichiometry.Then we’re surprised when students treat it like a complicated conversion trick instead of a way of counting matter. The mole is one of the most foundational ideas in chemistry. When students encounter it earlier in the year, they begin to see it as a universal counting system — not just a step in reaction math. Here is why moving the mole earlier changes everything. Teaching the mole early allows studen