Many of us have experienced one or both of these scenarios:

  • You’ve been hired for your first teaching job and given six sections of three different classes to teach.
  • A new school year is approaching. You get an email from the person in charge of scheduling, and they tell you that you’ve been assigned a class that you have not taught before.

What do you do?

These are some suggestions for dealing with either or both of these situations from someone who has been there during the course of 41 years of teaching.

How much time do you have?

Before you can plan on teaching your new class’s content, you must know how much time you have available to actually teach. Otherwise you’ll never get done what needs to be done.

For example, here is what can happen when the number of teaching days from the district calendar is compared to the reality of a typical school year (Figure 1).

Figure 1

When you take into account assemblies, mandatory state or national testing days, shortened professional development days, and the myriad of other things that pop up during the year (e.g., fire drills, sick days, snow days), you could have as few as 38 days to teach each quarter rather than the expected 46. And that doesn’t mean that each period will meet for the same amount of time!

Now that you know how much time you (probably) have, what are you going to do with that time?

My experience has been that spending more than 10–15 days on a unit of instruction without some closure results in the most distant information being pushed out of memory to make way for the new material in students’ minds. This means that an instruction unit should not last more than 15 days before it is tested.

So with 38 days of instructional time per quarter, you can have

  • three 10-day units, with eight days for review and testing;
  • two 10-day units, one 15-day unit, and three days for review and testing; or
  • some other combination that fits your needs.

Here is an example of how the curriculum for a one-year college-prep high school chemistry class was divided up in a 180-day school year (Figure 2).

Figure 2

Available time and “beginning with the end”

Now that you know how many instructional units you can fit into each quarter and semester, how do you decide what to do with the time?

Here is an illustration of a possible thought process (Figure 3):

Figure 3

What does “begin with the end in mind” mean?

  • Next Generation Science Standards (NGSS) or state standards,
  • district goals and objectives,
  • state testing requirements,
  • AP or IB requirements, and/or
  • topics/chapters in the textbook.

A few lucky teachers will have only one of these end-of-course targets to aim for, but most will have at least two, and possibly three. For example, NGSS or state standards and the topics/chapters in the textbook are probably common goals.

NGSS or state standards will lay out for you the larger overriding goals, but figuring out how you will organize the instruction to achieve these larger goals will require more specific learning objectives. So once again you can “begin with the end in mind.”

Available time and teaching the content

Here is a statement from NGSS about the goals of teaching the manipulation of chemical reactions (Figure 4).

Figure 4

And here is an example of learning objectives to guide students to understanding equilibrium (Figure 5).

Figure 5

And finally, an example of the correlated learning activities to teach the equilibrium objectives (Figure 6).

Figure 6

The process of choosing what to use to teach the objectives is shown in Fig. 3 and is a function of:

How much time is allotted to the unit? Is it a 5-, 10-, or 15-day unit? The allotted time should be the deciding factor in selecting what learning activities to do to teach the selected objectives. Changing a unit’s due date by more than one or two days will cut into the time available for future units and send the message to the students that they can lessen what they will be asked to do by their learning behavior. The students do not know what will be required in future units, so if the current unit runs a little bit long, because inquiry does take time, then the teacher could change intended activities in future units. This will allot more time for the current unit and shorten future units without changing the number of units or learning objectives during the semester.

Are resources available? It is hard to do labs and hands-on activities if there are few teaching resources available. Knowing what is available early on allows a teacher to be on the lookout for resources, be more creative in finding the funds or assistance to help obtain the needed teaching resources, and plan the time to find and obtain them.

How difficult are the objectives? The greater the difficulty, the more varied and scaffolded the learning activities need to be, and the more time is needed to do the learning activities.

Do each of the learning activities work? Does the activity result in students learning what the objectives are stating? Is the material presented in a clear and appropriate manner? When students complete the worksheet, are the questions helping them better understand the objectives? Can students get reliable data from the lab? In other words, do the activities throughout the unit lead to a clear understanding of the objectives for the students?

There is very little in a high school chemistry class that an average student cannot understand and learn if they make the effort and put in the necessary time. The number of units to complete each semester, and consequently the time allotted to each unit, can be adjusted the next year during the revision process of the course. Changing the number of activities during a unit or units during the semester can lead to student behaviors that improve the learning environment.

No plan is perfect! You may not be where you want to be at the end of each unit, but knowing that your plan will need to be adjusted over the next one, two, or more years is all part of the fun and challenge of being a science teacher!

Having a semester or yearlong plan lets the teacher know where the course is going, communicate this information to the students and parents, talk to the students about how what they are doing in unit X is related to what they will learn in unit Y, defend the curriculum when needed, and keep track of what works and what needs to be fixed for the next year(s). “Winging it” each year may sound like a method for adjusting to students needs, but in reality it only makes the teaching job more difficult and time-consuming. Why would anyone want to do that to him- or herself?


These steps will help anyone who has been assigned a new class to teach get started and do so with a plan. Without a plan of how to use the available class time, the teacher can become stressed, and the students will be creative in finding ways to get the teacher off-task to slow down the progress of the curriculum. Students have many fun and creative skills!

Good luck teaching your new courses!


Figure 3 is based on a similar diagram that the author found in an unremembered science education book from the 1980s.

Figures 1, 2, 4, and 5 are from chemistry units written by the author.

Thanks to Dr. John Stiles for revisions and feedback during the writing of this article.