Introductory Chemistry is a challenging course for some students, as it involves the application of concepts from algebra and other disciplines, as well as problem solving. Like many teachers, I try to help students overcome this challenge by creating an engaging and collaborative learning environment. I also try to accommodate a variety of learning styles by presenting lectures that use color to help make some of the concepts more intuitive for students.

What I find works best is using a chalkboard and several different colored pieces of chalk to model how to solve a sample problem — and the same goal can be achieved through the use of a white board and colored markers, or projecting a tablet screen using apps such as Educreations or Explain Everything. In this article, I’ll share some of the strategies that underlie this approach, and also provide some examples of the technique in practice.

The thinking behind the colors

Students can be categorized into visual, auditory, or kinesthetic learners, and often rely on a certain degree of each style during lectures. An ideal learning environment should provide pedagogical interventions and opportunities to cater to each type of learner.

Auditory and kinesthetic learners respond well to classroom lectures and hands-on problem-solving sessions. But what’s the best way to convey abstract chemistry concepts to students who are visual learners? In my experience, a simple classroom intervention, such as using colored chalks or pens can help these students grasp chemistry concepts that might otherwise elude them, especially at the introductory level. To name just two examples, I’ve successfully used this approach to help students identify chemical species and isolate unknowns during problem-solving sessions.

Areas of impact

One of the impacts of using colors is to clear up misconceptions about compounds and molecules. When elements have more than one letter in their symbol — for example, Cl — students may get confused. Are C and l part of the same element? Is the second symbol a number 1 (#1), a lower case letter l (L), or a capital letter I (eye)?

Likewise, if I’m writing a problem for students involving carbon tetrachloride, I could simply represent it as CCl₄. But I’ve found that my students seem to grasp its meaning more readily if I use color to separate the elements within it — as in CCl₄. Doing so allows my students to more easily see that not only does the red C stand for carbon and the blue Cl represent chlorine, but that Cl is the combination of the letters C and l (and not C1 or CI). The use of color also makes it clear that the subscript 4 is associated with the Cl and not with the C — a great help when we move on to topics such as balancing equations.

A second impact is helping students balance equations with polyatomic ions. Before I started using color in my teaching, I often saw students try to balance polyatomic ions as individual elements instead of considering the polyatomic ion as a whole. When I’m discussing balancing equations, I use colors to accentuate various polyatomic ions in the chemical equation. In this case, the polyatomic ions nitrate, NO₃^-1 and phosphate, PO₄^-3 as well as the other chemical species Mg, and Na are each represented using different colors. It’s the difference between:

3 Mg(NO₃)₂ (aq) + 2 Na₃PO₄ (aq) → 6 NaNO₃ (aq) + 1 Mg₃(PO₄)₂ (s)

vs.

3 Mg(NO₃)₂ (aq) + 2 Na₃ PO₄ (aq) → 6 NaNO₃ (aq) + 1 Mg₃(PO₄)₂ (s)

Without the use of colors, students tend to balance individual elements like O, P, and N — an approach that is cumbersome and difficult. But when identifying colors are used, they are reminded to balance the polyatomic ions as individual units while balancing the reaction.

A third impact is aiding students in problem solving to identify known and unknown entities. In my experience, some students can be overwhelmed by reading word problems and identifying given information, as well as determining what needs to be calculated. Consider the word problem below, shown as it might appear in a standard test:

Problem:

Vicks NyQuil™ is used as medication for the common cold. 30.0 mL of NyQuil™ contains 6.50×10^-1g of acetaminophen as an active ingredient for fever and pain relief. If the density of NyQuil™ is ~ 1.175 g/mL, calculate the mass % of acetaminophen in NyQuil™.

As an alternative, consider how the instructions could use color to help students organize their approach to solving the problem:

1. Underline/circle the numbers and write down what is given to you in the “given” section. The known parameters are presented in blue.

2. Then write down the unknown parameters that need to be calculated in red. Use highlighting to distinguish between significant and insignificant figures.

3. Determine how you go from known to unknown.

Click play on the video below to watch the instructions in action.

Student survey data

In fall 2014, I polled my class to assess the impact of colorful learning after a semester of instruction. Among ~ 40 students, the overwhelming sentiment suggested that colorful learning assisted better visualization, promoted compartmentalization and connection of topics, and aided stepwise learning. Survey results are presented below.

Final thoughts

In my experience, adding colors to my introductory chemistry lectures resulted in more engaged students and allowed many of them to better visualize the chemistry concepts and problems presented. This technique assisted students in identifying necessary steps to solve problems systematically, compartmentalizing ideas, connecting concepts, and organizing content. As shown in survey data, about 92% of students liked and recommended this lecture method in future courses.

Based on this feedback, I have been using colored chalk during lectures in most of my courses. Teaching and learning is an ongoing process, and this is a small step toward assisting students with learning chemistry. This pedagogical intervention has helped me portray a bigger picture of chemistry by isolating the simpler concepts with various colors.

Acknowledgements

I would like to acknowledge the support of Department of Chemistry & Physics, Salem State University and Salem State University for providing an opportunity to design and adopt innovative teaching strategies in my classrooms. I would like to thank my students for contributing toward a rewarding teaching experience and sharing their creative ways of learning.