10 Rules for Chalk Talks: How to give an effective lecture using chalk and blackboard

by Quirino Sugon Jr.

Chalk talk is one of the oldest way of giving lectures.   But to use this method well, you need to know ten principles:

Chalk talk: Phase angle in oscillations

1. Begin with the end in mind.  Before starting your lecture, ask yourself what is the ultimate goal of the lecture.  Is it to prove a theorem, to discuss a law, to demonstrate a phenomenon?  Write it down in one sentence.  This is your topic sentence for an hour or an hour and a half of lecture.  But if your students are not adequately prepared to handle your topic, e.g. they don’t know integral calculus but only derivatives, you may backtrack and provide introductory material–just enough for them to understand your lecture.  If your students already know the topic, junk whatever you have prepared and proceed to the next lesson.
2. Divide each 50 minute lecture into at most 5 parts. You have only 5 fingers per hand. The brain can only remember at most 7 new things using short-term memory. So do not rack up your your students’s brains by giving them more things than they can associate with their five fingers. A good exercise is to write a four to five sentence abstract of your lecture: state the problem, state what you assume your students know, explain your method, and outline your expected results, and decide on your evaluation tools.  Your evaluation tool can be as simple as getting half of your students to nod when you make a point or as tough as getting perfect in your 20-point quiz.
3. Plan your teaching strategy. There are many ways to deliver a lesson. You can start from general law or theorem and give specific examples of its applications. This is called the deductive method. Or you can start from specific examples in order to lead to the general law. This is called the inductive method. The most important thing is this: you must always start from what your students know and slowly lead them to new things they do not know.
4. Divide the blackboard into four parts. The blackboard is naturally divided into two. So divide each part further into two to give four sections. I am talking about standard blackboard sizes for a class of 50 students. As a rule of thumb, each blackboard section should be at most as far as your two arms can span and at least as far as your left shoulder to the tip of your right hand outstretched.
5. Do not talk and write at the same time. When you talk, don’t write. When you write, don’t talk. Talking is the time for resting your hands. Writing is the time for resting your throat. If you write and talk at the same time, you’ll easily get tired even after 30 minutes. Besides, you students also needs time to take notes and digest what you have said.
6. Never write with your students looking at your back. As much as possible, write with your shoulder perpendicular to the blackboard.   In this way, you can see what you are writing and you can use your peripheral vision to know what is happening in your class. Some may be raising their hands to ask a question, to request permission to go out, or to throw something at you. If you spend too much time looking at the blackboard, you may end up with half your students gone; the rest may be playing card games or taking videos. And before you know it, you are in You Tube.
7. Write from left to write. Since we read from left-to-write, write also in the blackboard from left-to-write, assuming that you are facing the blackboard. Start with the leftmost section, fill it up from top to bottom, then proceed to the next section until you reach the rightmost section. If you have filled the rightmost section, go back to the leftmost section, erase its contents, and write anew. Repeat the whole process.
8. Remember that teaching is drama.  You are an actor whether you like it or not.  The podium is your stage and your students are your audience.  Make eye contact when speaking, by shifting your gaze from left to right.  Make sure that your voice is heard even by those sitting at the back.  Vary your voice to emphasize your point.  Let your points sink in using long pauses.  Sometimes, it is helpful to ask one of your students to be the actor by asking him to graph an equation or show his solution.  Sit in one of the chairs with your students.  Observe what they are doing.  Check out the blackboard layout if it is pleasing to the eye.  Ask the student volunteer probing questions and correct his answers.  Then take your turn at the podium.
9. Use colored chalks.  A blackboard filled with white chalk is dull.  Underline the section headings with colored chalk.  Use different colors for different graphs.  Practice drawing freehand different shapes: parallel lines, perpendicular lines, rectangles, circles, and ellipses.  Then move to 3D objects like parallelpiped, cubes, pyramids, cones, and spheres.  If possible, use the opportunity to teach your students how to draw, too.  Never label the arrows or lenghts or points in your diagrams without asking your students.  The best way to teach is through dialogue and one of the best way to facilitate this dialogue is the chalk.
10. All’s well that ends well. If you still have few minutes left, give a short summary of what will happen in the next lecture. In this way, you can prevent the bad practice of dismissing the class before the bell rings.  If you are in a Catholic institution, end with a prayer–an Our Father, a Hail Mary, a Glory Be, or Angel of God.  And don’t forget the Sign of the Cross. You are not sure if you will still see your students tomorrow.  Death is always an unexpected thing.  So it is always best to prepare for a good death to go to heaven by praying before and after class.