31 January 2011

Comments for K-12 STEM education

Today is the deadline for submitting comments to the NITRD request for information on strategies for meeting the goals set out in the recent PCAST report: "Designing a Digital Future: Federally Funded Research and Development in Networking and Information Technology" (Dec 2010).

The first 2 comment sections relate to particular industries (health case, energy, transportation, ...) or R&D, but the third section asks specifically about strategies for incorporating computer science into K-12 STEM education.

The rest of this post contains the comments that I submitted:

3. The PCAST report calls for fundamental changes in K-12 STEM education in the United States, including the incorporation of computer science (CS) as an essential component.

a. What CS concepts are important to effective elementary, secondary, and post-secondary curricula? Among these concepts, which are commonly found in curricula today? Which are missing?

Elementary: (3rd-5th)

Currently, elementary schools are likely to cover "logic grid" puzzles and syllogisms, but not much more. Ideally, they should include at least the following:

  • Number systems (specifically binary, octal and hexadecimal since these are the ones that matter for computer science)
  • Boolean logic (and, or, xor, not): boolean variables and expressions
  • Introduce the concept of simple variables (integer) here and relate to boolean values (x = 3 is either true or false)

Including a variety of different logic puzzles (Sudoku and similar) would also be beneficial.

In addition, elementary school should also cover the skills necessary to use a computer effectively and perform common tasks (word processing, web search, ...). This is necessary so that they are comfortable using computers when we introduce programming in later grades.

Middle School: (6th-8th)

In these grades, students should focus on understanding how computers work and learning how to write a basic program.

As part of "understanding how computers work", we need to demystify the operation of the computer. This is important because learning how to program doesn't give a complete picture of how computers operate. This section should include the following:

  • Basic file formats (show how text, graphics, music and video are stored on a computer; explain difference between bitmap and vector graphics, and text vs. rich-text formats)
  • How color is encoded (RGB encoding, compare with primary colors they were taught in elementary school)
  • How computers work (basic description of how computers perform logic and math operations) 
  • Basic boolean algebra (DeMorgan's law, re-writing expressions)
  • Simple electronics (hardwire or programmatically control an LED)
  • Internet: What happens when a website is visited? How does the internet route traffic? 

For "how to write a basic program":

  • Programming constructs: variables, control flow, functions, objects, ... (exact set varies depending on languages chosen)
  • Write simple programs (see below)
  • Explore and contrast various general-purpose vs. special-purpose languages
  • Using wildcards and regular expressions (in a programming language and in a shell/cmd prompt)

When having the student write simple programs, it is important that the core assignments are interesting and engaging. The best way to accomplish this is by having the project require significant creative input from the student. For example, creative writing for a text adventure or drawings for a 2D game. This approach gets the student to invest in the success of the project (since it's their story or artwork), so they are more motivated to learn how to make their characters work they way they want.

Note that rather than arguing about which programming language to teach, we should focus on introducing students to a number of different languages (at least 2 or 3). This is useful because each language has different strengths and weaknesses, and we don't want students to graduate thinking there is only one way to program. Frankly, I would expect the languages chosen to vary somewhat between school systems and the change over time.

In addition, in these grades it is also important to start teaching students about electronic privacy, security and information sharing. It makes sense to teach these subjects in the context of computer science and to give the students programming assignments that (directly or indirectly) explore these topics.

The goal should be for all 8th graders to graduate knowing that they (1) are capable of writing (simple) computer programs, and (2) have a basic understanding of how computers work.

High School: (9th-12th)

High school should introduce advanced programming topics (algorithms and data structures) just like high schools offer advanced chemistry and physics classes. Beyond 9th or 10th grade, these classes don't have to be required for all students, but they should be required for students interested in a science and technology track.


Overall, we should try to link CS projects to other subjects whenever it makes sense: We can motivate learning about trigonometry by showing how it is used in games to calculate distance and to detect (bounding sphere) collisions. We can talk about the math/physics behind gravity and acceleration when we want to have a character jump realistically on the screen. We can demonstrate the additive color properties of light and discuss prisms and rainbows when we introduce RGB color.

Once we have CS as a core subject, these links will be easier to make and will lead to a much richer learning environment for the students.

b. What do teachers need (including preparation and training, tools, and resources) to be able to deliver CS education effectively?

Training and ready-to-use classroom materials are key for all grade levels. Any materials that are created need to be supplemented with instructions showing how to use it properly in the classroom. Two types of instructors should be targetted here: teachers who know how to manage a class but are not very familiar with programming, and teachers who know how to program but are not familiar with teaching strategies and classroom management. These two groups are likely to make up the bulk of teachers during the first years when we introduce CS to the classroom.

There will also need to be programs offered for teachers to learn how to teach this material. Fortunately, most (if not all) school systems require regular teacher training for "clock hours". This is the perfect venue for reaching the teachers and bringing them up to speed with the material.

c. What factors are important in promoting student interest in CS?

I discussed some factors in the earlier sections, but the most important factor is simply that computer science needs to be included as part of the core K-12 curriculum.

An example which underscores the importance of this happened recently to a friend of mine. His daughter (age 12) had already taken a programming class or two and she was interested in participating in an after-school robotics class. However, even though she was interested, she decided not to sign up because none of her friends were planning to take the class and she didn't want to be "alone". Whenever I think about this, I wonder how many other students are missing out because of (even minimal) social pressures, and how many of her friends would have discovered that this was a subject that was interesting to them, if only they had been forced to try.

And remember, this was for someone lucky enough to have encouraging parents and teachers willing to organize this after-school class. Most students don't have those advantages.

I'm tempted to say that adding CS to the core is the only important factor and that it (almost) doesn't matter what we teach or how we teach it. Once we make CS a core requirement, everything else will (by necessity) follow. Of course, it's clearly better to teach it properly, but as long as we're willing to iterate and improve, even a less-than-perfect rollout will be of great benefit to the students.