Delivery Styles - Lecture

I am sometimes asked which instructional delivery system I think is best: traditional lecture lab, self paced, or computer aided and online. Like a trick question, the answer is all of the above. Each method has strengths and weaknesses. I have used each at different times in my career and enjoyed the advantages and suffered the frustrations of each of these delivery styles. Most people are familiar with the lecture format. In fact, to many people the other formats are not really teaching. I do not agree with that sentiment, but I understand why people sometimes feel that way. I will talk today about the lecture format and cover the others in later columns.

Undoubtedly, the lecture format is efficient at disseminating information to large numbers of people. If we are honest, it also appeals to the ham in most instructors: we like to talk! I will admit that I enjoy lecturing, and I believe my students enjoy my lectures. However, I may not be the most objective judge. Lectures can be engaging with good preparation and a well developed style. However, they can also be deadly. The derisive terms “talking head” and “chalk and talk” are well deserved. Did you ever see a video that is basically a picture of someone while lecturing? Usually they are hard to sit through. After watching a few I decided that the reason the videos of my lectures were boring was that the original lectures were boring. I was talking, and talking, and talking and I am sure the students were nodding off. Remember, your job is not to just cover all the topics, it is to teach your students. A big problem with lecture is that people do not tend to retain most of the information they hear, active participation is needed to retain the information. A few ideas to increase student participation are taking notes (not a big hit with students), asking students questions, asking leading questions, regularly entertaining questions from students, or engaging them in a dialogue. I like the dialogue format. Today, I don’t tend to talk to my students as much as have a structured discussion encouraging their participation and asking them questions. Repetition is also good. If something is important, don’t just say it once, say it several times using different approaches. After you think the students know the information, ask some questions to find out.

Speaking style and delivery is important, but can vary a great deal from one person to the next. In general, you need to be interested in what you are saying. Students can hear the interest and passion in your voice. They can also hear disinterest and lethargy. You need to be interested and excited about your field. Humor works for some speakers, everyone loves to laugh. Don’t feel compelled to tell a joke, just use humor if it comes naturally. Stay away from jokes involving off color, racial, religious, or political jokes. Jokes on yourself are fairly safe and students enjoy a laugh at the instructor’s expense. Most people find stories more engaging than a recitation of facts. Having taught for many years, I have a large body of stories to draw on.

Visual aids are great for creating interest. Rather than draw a crude diagram of something on the board, pass around examples of the real thing. If you have a video projector and document camera you can zoom in on parts and show details to the whole class that are not easily visible even to someone holding the object. The table in front of where I lecture is usually a mess because it is covered in stuff I brought in from the lab to show. The ultimate visual aid was a complete transport refrigeration unit sitting in the corner of the class room when we were teaching transport refrigeration. Students disassembled the unit, brought the frame and pieces into the class room, and then reassembled the unit in the corner. When I talked about the location of parts I could actually put my hand on the part on the unit. We gave tests using sticky notes attached to components and students were required to identify components. They would come up, look at the component labeled #1, and write down its name and function. That room is now used for an Interior design class and for some reason they did not want a refer unit in the corner, so we disassembled it and took it out of the room.

Powerpoint presentations can also help, but avoid letting the powerpoint presentation BE the lecture. Nothing is more boring than hearing someone read the text of a powerpoint presentation. I remember being surprised when several students mentioned to me that another instructor’s classes were boring. This instructor had really world class powerpoints that he had developed. They were complete with movement, animation, great details, and good photos. In fact I was rather envious of them. However, the students said they started to doze off as soon as the lights were out. They were not actively participating and they tuned out. This is not to say you shouldn’t use powerpoint presentations, just remember that they are a supplement, not a replacement.

Personally I feel that the biggest weakness of traditional lecture lab is the lab component when five people are assigned to work together on something that really only requires one person. I will leave that discussion for next time.

A Father's Legacy

When I was 13 years old my father started Stanfield Air Systems. He moved his family to a city he had never lived or worked in to start a brand new business in a field he knew little about. For capital, he used his life savings and a line of credit. It was not until many years later when I had my own family that I truly understood the courage it took for my parents to do this. He gave up a secure job with a major corporation that had just offered him a promotion. He was one of a class of businessmen recruited to start air conditioning dealerships. After five years, he was the only one of his class still in business. Stanfield Air Systems survived major builders declaring bankruptcy and not paying, strikes by compressor manufacturers when equipment was hard to get, and more than one economic downturn. Because of dad’s pioneering spirit, Stanfield Air Systems has frequently been in the vanguard of new or unique technology. We put in solar systems in the late 70s and water source heat pumps in the 80s. Some of the more unusual equipment we installed included Space Pack high velocity systems, Amana EG units, and Arkla Servel absorption chillers. People around Athens learned that if you wanted to do something out of the ordinary and be successful, you wanted dad’s company to do it. One thing that has stayed constant is a commitment to quality. He sold himself and his company, not any particular brand and certainly not price. His price was usually higher than the competition, but he offered services and quality not available elsewhere.

I have a brother and a sister, and we all work in the air conditioning field. My sister now runs Stanfield Air Systems and they are doing great. They remain the company people who insist on quality turn to. I am especially proud of the pictures in my book that came from Stanfield Air Systems showing what a good installation looks like. My brother is a top service technician – for the competition. He has customers that call and ask for him by name because he has the same commitment to quality service and honesty as our father. And I teach air conditioning at Athens Technical College. I am proud to say that many of the technicians at Stanfield Air Systems graduated from Athens Tech. For that matter, so did many of the technicians at competing companies. In Athens Georgia, if someone comes to your house to install or service heating and air conditioning equipment, there is a pretty good chance that they are a Stanfield, work for a Stanfield, or were taught by a Stanfield. My father’s legacy includes a legion of air conditioning professionals and three children who are proud to call him dad. I know my recent success started in 1968 when a courageous entrepreneur put everything on the line to start a new company in a new town. Happy father’s day dad!

A Father's Legacy

When I was 13 years old my father started Stanfield Air Systems. He moved his family to a city he had never lived or worked in to start a brand new business in a field he knew little about. For capital, he used his life savings and a line of credit. It was not until many years later when I had my own family that I truly understood the courage it took for my parents to do this. He gave up a secure job with a major corporation that had just offered him a promotion. He was one of a class of businessmen recruited to start air conditioning dealerships. After five years, he was the only one of his class still in business. Stanfield Air Systems survived major builders declaring bankruptcy and not paying, strikes by compressor manufacturers when equipment was hard to get, and more than one economic downturn. Because of dad’s pioneering spirit, Stanfield Air Systems has frequently been in the vanguard of new or unique technology. We put in solar systems in the late 70s and water source heat pumps in the 80s. Some of the more unusual equipment we installed included Space Pack high velocity systems, Amana EG units, and Arkla Servel absorption chillers. People around Athens learned that if you wanted to do something out of the ordinary and be successful, you wanted dad’s company to do it. One thing that has stayed constant is a commitment to quality. He sold himself and his company, not any particular brand and certainly not price. His price was usually higher than the competition, but he offered services and quality not available elsewhere.

I have a brother and a sister, and we all work in the air conditioning field. My sister now runs Stanfield Air Systems and they are doing great. They remain the company people who insist on quality turn to. I am especially proud of the pictures in my book that came from Stanfield Air Systems showing what a good installation looks like. My brother is a top service technician – for the competition. He has customers that call and ask for him by name because he has the same commitment to quality service and honesty as our father. And I teach air conditioning at Athens Technical College. I am proud to say that many of the technicians at Stanfield Air Systems graduated from Athens Tech. For that matter, so did many of the technicians at competing companies. In Athens Georgia, if someone comes to your house to install or service heating and air conditioning equipment, there is a pretty good chance that they are a Stanfield, work for a Stanfield, or were taught by a Stanfield. My father’s legacy includes a legion of air conditioning professionals and three children who are proud to call him dad. I know my recent success started in 1968 when a courageous entrepreneur put everything on the line to start a new company in a new town. Happy father’s day dad!

Be a Problem solver

Have you ever known someone that excels in finding the cloud behind the silver lining? Some people have a knack for finding the negative to any set of circumstances. Sometimes students can get the impression that a service technician’s job is to find problems. But in truth, the technician’s job is to solve problems. Yes, you have to identify a problem to solve it, but solving the problem is the goal. Customers and employers are more impressed by people that find solutions than people that find problems. Most people already have more than enough problems, so the last person they want around is someone who generates more problems than solutions. On the other hand, people that excel in finding solutions are a joy to have around. Encourage your students to offer solutions to the problems they find. They need to become practiced in providing solutions, not just identifying problems. This can sometimes be a matter of attitude. Rather than finding reasons why something cannot be accomplished, look for ways to overcome the barriers to get the job done. This attitude should start with the way you interact with your students. Make sure to recognize what they do correctly, and not simply point out their errors. Of course you need to correct their errors, but it should be done constructively, not destructively. Always offer a better way when correcting students who are struggling. The student who is trying to glob on solder that is balling up and falling off really does not have to be told that what he is doing is not working; he can see it for himself. What he needs is someone to offer a better way. Students who gain skills after struggling at first appreciate the accomplishment more. You can teach more than any particular skill when you help a student overcome a learning barrier, you teach them how to be a problem solver.

Understanding Relays and Contactors

I promised last week to reveal my secret for teaching relays. I know I sound like a broken record, but the first step is making sure that the students have the necessary electrical foundation knowledge. Before introducing relays and contactors, students must clearly understand circuits, loads, and switches. A relay is essentially an electrically operated switch. A contactor is really just a bigger relay. The key to understanding relay operation is realizing that a relay is actually two electrical devices: a set of contacts and a coil. The contacts are a switch. They are wired in circuits exactly like switches and they behave like switches because they are switches. Relay coils are loads; specifically, solenoids. They wire in circuits like a solenoid and they behave like solenoids because they are solenoids. The purpose of the relay coil is to operate the relay contacts. Energizing or de-energizing the relay coil makes the contacts open or close, but the coil and contacts are almost always in separate circuits. This is difficult for many students to understand. What they see is a box with a lot of electrical connections. To demonstrate how a relay works I ask the student to wire a toggle switch to control a light. Then I ask them to wire another circuit to a relay with a 120 volt coil the same way, with a toggle switch controlling the relay coil. Make sure and reinforce the idea that the coil is a load. The student should operate the circuit and hear the relay click when the switch is closed. Have the student check the continuity across the contacts with the coil de-energized, then have them operate the relay coil and check the continuity again. If you are using a relay with both normally open and normally closed contacts they should check both. Now have the student combine the circuit to the light they wired earlier with the relay by replacing the toggle switch controlling the light with the relay contacts. This illustrates that the contacts are just a switch. Now have the student operate the relay to see it control the light. Next, mention that the coil and contacts do not have to be the same voltage. Have the student wire a toggle switch and a 24 volt transformer to control a 24 volt relay coil. Then have them use the relay contacts to control a 120 volt light. If you want to extend the HVAC/R component analogy you can replace the toggle switch with a thermostat, explaining that a thermostat is simply a switch. Before leaving the exercise, find a schematic diagram and show the circuit with the relay coil and the circuit with the relay contacts to illustrate that they are in separate circuits. You can point out that the labeling identifies which relay contacts are controlled by which relay coils. Figure 32-23 in Fundamentals of HVAC/R shows a simple diagram with a 24 volt contactor controlling a compressor. The figure shows that the coil in the 24 volt circuit is controlling the contacts in the 230 volt circuit. Building the circuits to the relay in steps helps students understand how relays operate by relating the relay coil and the relay contacts to components the student already understands.

There are many resources for teaching relays and contactors in Fundamentals of HVAC/R. Unit 29 contains good discussion and illustrations of how relays operate in 29.7 Relays and Contactors. Contactors are discussed and illustrated in 32.16 Contactors in Unit 32. Diagrams using relay and contactor circuits are discussed extensively throughout Unit 33.

Teaching Ladder Diagrams

Reading electrical diagrams is a crucial skill that HVAC/R students must master. That is why all HVAC/R curriculums spend a lot of time discussing how to read electrical diagrams. Many students struggle with this even though every HVAC/R instructor I have ever met emphasizes diagrams. I believe this is because students must learn several pieces of information and then weave them all together in order to truly understand electrical diagrams. You really can’t understand diagrams if you don’t understand the basic function and operation of standard electrical components. Learning symbols for components that you don’t understand is like memorizing words in a foreign language without knowing what they mean. You still can’t read. Understanding basic circuits is also a must. Students should be able to construct basic circuits consisting of loads and switches. Finally, they must have a good concept of how the system they are working on heats or cools. If all this is in place they usually will have no problem learning how to read electrical diagrams. I find that students who are the weakest with diagrams are usually also weak in one or more of these foundation areas. After all, a diagram is simply a representation of a collection of circuits that are made up of electrical components. You really can’t understand an abstract representation if you don’t understand the actual component that you can see and touch. So we start by having students build basic circuits with switches and lights in order to learn how loads and switches work in a basic circuit. Loads should have a voltage drop when current passes through them, switches should not. Then we introduce components and relate them to either loads or switches. So thermostats are switches while motors are loads. Introduce symbols and have students draw symbols for selected components. Then have them identify components on a unit using the unit diagram. The most difficult components for students to grasp are usually contactors and relays. Understanding relays is a big stumbling point for many students. I have a method for teaching relays, but I will save that for another article. Just know that there is no use trying to explain a ladder diagram that contains 24 volt control relays to someone that does not understand how relays work. After explaining basic ladder diagrams and showing several examples ask the students to draw a simple diagram of a packages air conditioning unit without looking at an example. You don’t want a copy of the book; you want to see how much they understand. There will be lots of weeping and gnashing of teeth. Students will complain that they are not artists and that drawing diagrams is not necessary to service systems. However, you will find out quickly how much they understand about circuits, components, and diagrams. People that understand diagrams can draw them. Be patient, suggest corrections, and have them revise their diagrams until they have something that will work. This typically takes several revisions for many students. Finally, have them wire the circuit that they drew using the actual components as much as possible. For safety we have a simple rule: the instructor has to check the circuit before it is energized. The pride the students get from seeing their circuit operate will offset the anguish they experienced getting there. Gradually add more complex circuits – two stage cooling, cooling and heating, heat pumps, or whatever makes sense for your area. After the students have a good command of ladder diagrams you can start discussing the many variations they will see in different manufacturer’s diagrams. There are as many variations as there are manufacturers, adding to the difficulty for aspiring technicians.

Diagrams are discussed extensively in Fundamentals of HVAC/R in units 31 Electrical Components and Wiring Diagrams, 32 Controls, and 33 Control Circuits and Diagrams. There are some great exercises in MyHVACLab to help students learn electrical diagrams including an interactive electrical symbol recognition activity and a virtual wiring exercise that aligns a ladder diagram to the actual components as they are wired.

Problem Solving

HVAC/R Service is about practical problem solving. All the tools, technology, training, and literature are just there to help us identify and solve problems. The primary skill that any service tech needs is problem solving. The most important tool at your disposal is your mind. I am frequently asked why we make students do BTU calculations of ice turning to steam, series parallel ohms law problems, gas law calculations, or any host of other primarily mental exercises that nearly all HVAC/R students must suffer through. Usually, the students asking are doing the most suffering. Although I can justify all of the above as an endeavor to garner a deeper understanding of the principles which make HVAC/R systems work, I usually tell them that you can’t become a champion weight lifter by lifting marshmallows. Service techs are not paid to connect gauges or take voltage readings, they are paid to solve problems. Obviously techs need to be familiar with all the tools at their disposal, but we should never overlook the fact that their primary tool sits on their shoulders. I am afraid the current focus on standardized testing throughout our educational system has not prepared our students for practical problem solving. Rather, they are used to selecting the best solution from a very limited set of answers. My prescription? Lots of work that requires students to recognize and define the problem, systematically find the cause, and offer a solution. Assign work that requires students to provide written answers. Ask questions whose answers have not been explicitly stated, but require students to put two pieces of information together. If you get an answer that is way off base, try and ask leading questions to help the student work their way through a solution to the problem. The exact answer is not as important as the process. Encouraging students to use their minds to solve problems is crucial. The shop is a great place to work on problem solving because real life problems are never as simple as a, b, c or d. But don’t accept “the part is bad” as an answer. The student should be able to explain what the unit is doing wrong, what is the cause, how they determined the cause of the problem, and what their proposed solution is. Truth be told, I believe this approach could work in a lot of fields besides HVAC/R. The leaders in any field are always people who have recognized and defined problems and then devised solutions.