How Deep is Deep Enough?

“Perfection is the enemy of the good”


Education is about depth. Generally, we start with overviews and the big picture. Then we move on filling in the gaps and providing additional information. To fulfill one of my general education requirements, I took an Introduction to Western Civilizations course. We covered the rise of western civilization from prehistory all the way up to the modern age. This course included only the most essential points.  If I had gone on and studied western history, we would have expanded on the main points covered in the Introduction to Western Civilizations course.

As an example, there were courses on the Middle Ages like The Medieval World and Introduction to Medieval People, and then going into more depth Medieval Women. Each course led to a narrower but deeper dive into the topic.

Another example of this depth occurred during my science education. In my Introductory Chemistry courses, we learned about the laws of thermodynamics; there are four laws if you include the zeroth law. The laws of thermodynamics were only a single chapter in my introductory textbook, covered in just a couple of class periods.

Several years later as part of physical chemistry, I took thermodynamics, a required course for chemistry and biochemistry majors.  We spent the entire course studying the laws of thermodynamics, including mathematically deriving all the laws from first principles.

While I have used a lot of my chemistry over the years, I’ve never used that deep dive into thermodynamics. There are fields and research areas where this information is needed, however, I wonder how many chemistry students need this deep a dive into thermodynamics.

Determining what to teach students and what depth they need to learn each of these topics is a critical point of the educational design process. There has recently been a change to a topic that all (US) science students need to cover, the International System of Units abbreviated SI for Système International d’unités or classically the metric system.

The SI system is the measurement system used in scientific research. The SI system has seven base units, and 22 (named) derived units (made by combine base units).   In the US we teach students the SI system because the US is one of three countries that didn’t adopt the SI system. Science students need to use the SI system; the question is how much they need to know about the system.

The French first established the original two unit’s, length (meter) and mass (kilogram) in 1795. The system was developed to replace the hundreds of local and regional systems of measurement that were hindering trade and commerce.  The idea was to create a system based on known physical properties that were easy to understand, this way anyone could create a reference standard.  The definition of the meter was 1/10,000,000 of the distance from the North Pole to the equator on the Meridian that ran through Paris. The Kilogram was the mass of 10cm³ or 1/1000 of a cubic meter of distilled water at 4°C.

Basing the units on physical properties was supposed to give everyone the ability to create standards, in practice difficulties in producing the standards meant the individually created standards varied widely.  In 1889 the definitions of the meter and kilogram were changed to an artifact standard; an artifact standard is a standard based on a physical object, in this case, a platinum-iridium rod and cylinder located just outside of Paris France.

The original Kilogram stored in several bell jars.
National Geographic magazine, Vol. 27, No.1 (January 1915), p. 154, on Google Books. Photo credited to US National Bureau of Standards, now National Institute of Standards and Technology (NIST).

The use of the artifact standers lasted for quite a while; however, as science progressed we needed more accurate standards and the definition’s changed again, the new idea was to define all the base units on universal physical constants.  Skipping over the krypton 86 definition, in the 1960s the definition of the meter was changed to the distance light travels in a vacuum in 1/299,792,458 of a second (3.3 nanoseconds).

The speed of light was chosen to define the meter because it contains the meter, the speed of light is 299,792,458 m/s. This definition might seem a little strange, but it makes a lot of sense.  The speed of light is a universal constant, no matter where you are the speed of light in a vacuum is the same. To determine the length of the meter, you measure how far light travels in 3.3 nanoseconds. If your scientific experiment requires higher precision, you can make a standard with higher accuracy, instead of using 3.3 nanoseconds you could measure how far light travel in 3.33564 nanoseconds.

On November 17, 2018, the definition of the kilogram changed at the 26th meeting of the General Conference on Weights and Measures. The new definition of the kilogram uses the Planck’s constant which is 6.62607015×10-34 Kg m2/s.  Like the meter, the definition of the kilogram applies a constant that contains the standard.  Just like the meter the determining the precision of the kilogram is dependent on the accuracy of the measurements.

Up to this point, we’ve taught the kilogram as an object; the definition of the kilogram was a cylinder just outside of Paris no matter what happened that cylinder was the kilogram. However, with these new definitions, it becomes possible for students to derive the standards themselves. Scientists at the National Institute of Standard and Technology (NIST) created a Kibble or watt balance, the device used to measure the Planck constant, built out of simple electronics and Legos.

It is surprisingly accurate (±1%) you can read about it here. Using the Kibble or watt balance, it would be possible to develop lab activities were students create a kilogram standard and then compare it to a high-quality purchased standard.

With the change to the kilogram standard, is now possible to use the metric system to teach universal constants and have the students derive all the SI standards based on observations and first principles. The real question is, should we? For the bulk of the science students and scientist for that matter, how deep does their knowledge of the SI system need to be? Most are not going to become metrologist’s the scientist that study measurements and measurement sciences. With the ever-growing amount of scientific information, we need to think about not only what we teach but how deep we teach. What do you think, students can now derive the standards of the SI system from first principles, should they? We can’t teach everything how do we determine what to teach and how much to teach?


Thanks for Listening to My Musings

The Teaching Cyborg

So, you think you can’t do Inquiry-based Learning: Better ask the gnome

“Scientific inquiry starts with observation. The more one can see, the more one can investigate.”
Martin Chalfie

In 1995 the National Research Council published the National Science Education Standards in which they recommended as one of its central point’s learning science through inquiry. As defined in the National Science Education Standards inquiry has two meanings:

Scientific inquiry refers to the diverse ways in which scientists study the natural world and propose explanations based on the evidence derived from their work. Inquiry also refers to the activities of students in which they develop knowledge and understanding of scientific ideas, as well as an understanding of how scientists study the natural world. (p23)

Five years later a companion book Inquiry and the National Science Education Standards: A Guide for Teaching and Learning was released. The purpose of this companion book was to help teachers understand and implement inquiry in their classrooms. In 2018 almost, a quarter of a century later implementation is still let’s be kind and say incomplete.

If we teach science as a method of looking at the world and asking questions Which is what science is instead of a collection of facts, principles, and ideas that many people view it as then the inquiry-based teaching method is critically important. So why isn’t inquiry-based STEM education universal?

The most common answer I hear is “I can’t do inquiry my class is too big.”  In my mind, this means you can collect bigger data sets. Followed closely by “My students aren’t ready for inquiry,” well instead of full inquiry try guided inquiry.  Lastly, “I have too much material to cover there is no time for inquiry.”  There might be something to say for that last statement, but that is a soapbox for another time, but I would say design your learning goals into the inquiry tasks.

Another way to address these questions, is to ask the question, does inquiry require complicated questions with lots of complicated equipment? Let’s ask a Gnome.

The Gnome Experiment

KERN the gnome in a case with his digital scale
Kern the gnome packed with his scale. Image: Gnome Experiment

The humble garden gnome is practically a cultural icon. To some garden gnomes are a passionate collectible, to others a novelty, and to still others the butt of the joke. However, there is one gnome that taught us about gravity while researching the physical makeup of our planet.

I think I first heard of the Gnome Experiment from a TED talk. The question proposed was could you measure the difference in gravity around the earth on a basic scale. To test their scales the Kern company got one of their scales a garden gnome and started shipping them around the world where the gnome’s recording weight and a picture at each stop. Here are some of the places the gnome has been

KERN the Gnome photographed in four different locations around the world.
Kern the gnome packed with his scale. Image: Gnome Experiment

The result of the experiment is a resounding yes. Kern the gnome weighed different amounts in different places.  Using a similar process what could you teach your students. While the phenomenon of gravity is simple to describe, it’s a difficult concept to grasp in real life.  Weight is dependent on gravity, and the amount of gravitational attraction on the surface of the Earth is dependent on the distance to the center of the planet and mass (density) of the material underneath you.  Apply this information correctly, and it can teach you about gravity and the earth.

For instance, suppose we were to conduct this experiment again.  Only this time in addition to the gnome and scale we also included a GPS/altimeter. I live in Colorado a quick search gives us a list of 20 roads that have an elevation over 12,000ft.  Suppose we took our gnome on a road trip and used our altimeter to measure the weight at 12,000ft on each of these roads. Since we have now controlled for elevation, what would it mean if we got different results?

As a teaching aid, the gnome experiment can be quite fun and useful. The idea that a garden gnome can be used to conduct science is a great icebreaker. More importantly, the Gnome Experiment shows how you can ask a genuine inquiry with a simple experiment and only a little bit of equipment. Stop and think about experiments you can ask you’re not asking your students to win the Nobel prize.  Think up some simple experiments and have your class address them.  I suspect what we need is a database of inquiry-based experiments for education, like the database of test and exam questions that are out there.


Thanks for listening to my musings

The Teaching Cyborg

So, You Think You Recognize the Words, But Do You?

I am sometimes amazed that human beings have any ability to communicate. Have you ever heard the statement “My blue is different than your blue”? One of the ideas behind this statement is if I take a blue object the way my brain processes that color is different than the way your brain processes it. This idea that perception might affect the ways each of us views the world is different from the technical definitions. With my science background, I might define blue as “light with a wavelength between 492-450 nm”. While the Merriam-Webster’s dictionary defines Blue as “1: of the color whose hue is that of the clear sky”.

Perception is not the only point to complicate communication. If you and I had just met and I showed you this cup of tea and said the word “solbränna.”

A cup of tea with milk, in a white cup on a white saucer. The saucer also holds two think rectangular cookies. It all sits on a maroon cloth.
A cup of tea with a cookie Photo by Paul Bowney, CC BY 2.0

Would you know what the word meant? Do I mean tea, cup, saucer, cookie, liquid, hot, how many options are there? Think about it for a while and see what you think. (Take your fingers off the keyboard I didn’t say Google the word!)

I could continue with different ideas showing the complexities of human communication. However, I think this should be good enough to highlight why I think it is amazing any two people can communicate at all. Yes, I hear you “At least within a given group it’s easy. We learn to speak using the same words as everyone else”. Okay, I’m going to give you a list of words.

  • Theory:
  • Law:
  • Insult:
  • Abstract:
  • Significant:
  • Sensitive:

These are all words in the English language. Words that most people can define. In fact, from an educational standpoint, most people knew these words before they started college. So, let me ask you when you’re teaching or giving a presentation do you think about the meaning of the words you are using? Perhaps more importantly do you think about what definitions your audience might be using?

What got me thinking about this was a recent debate I saw about the theory of evolution. What got to me was the fact that the two individuals were talking about two entirely different things. In fact, one of the most common arguments against evolution involves the word theory. People state that we can ignore evolution, or we should teach other things than evolution because after all evolution is just a theory. So, let’s get back to the list of words have you thought about them? What are your definitions?

Did you come up with these definitions?

  • Theory:
    • an unproved assumption: conjecture
  • Law:
    • a binding custom or practice of a community
  • Insult:
    • to treat with insolence, indignity, or contempt
  • Abstract:
    • disassociated from any specific instance
  • Significant:
    • having meaning
  • Sensitive:
    • receptive to sense impressions

How about these definitions?

  • Theory:
    • is a more or less verified explanation accounting for a body of known facts and phenomena.
  • Law:
    • A virtually irrefutable conclusion or explanation of a phenomenon.
  • Insult:
    • An injury, attack, or trauma.
  • Abstract:
    • A condensation or summary of a scientific or literary article or address.
  • Significant:
    • In statistics, denoting the reliability of a finding or, conversely, the probability of the finding being the result of chance.
  • Sensitive:
    • Responding to a stimulus

No matter which set of definitions you choose you are correct. The first set comes from the Merriam-Webster dictionary, while the second set comes from my high school science textbook (interestingly many of these words are not in college texts) and Stedman’s Medical Dictionary. The reason for these different definitions is that in science or any intellectual pursuit existing words are often given new meanings to meet the needs of the field. Since these definitions apply to specific fields, they are not necessarily the general definitions that the public knows.

Let’s apply this to our two debaters if we look at what each said we can see the differences. When the scientist said the theory of evolution he meant “Evolution is a phenomenon that is supported by many scientific studies and experiments over a long period of time.” When his opponent said the theory of evolution, he means “A guess as to how life came to exist as it is.” While I’m not suggesting everyone would have suddenly agreed with each other about the whole concept of evolution if they had taken a little bit time to clarify their meanings they at least could have debated the actual experimental studies of the topics (I know its a dream).

These differences in definitions are one of the reasons it is so important to learn and teach the language of your field. However, when you’re designing your lessons or planning an article do you ever stop and think about what your audience already knows? If you seem to have problems communicating with someone, do you think about how your definitions may vary from there’s? Does your field have definitions outside the common parlance? Do you think about this enough when you are communicating? Lastly, why don’t we use the most powerful of all language tools and coin new words when we need them? It might make communication a little bit easier.  After all, things are just going to get worse, according to this New York Times article, the word Run now has 645 meanings.


Thanks for listening to my musings

The Teaching Cyborg


P.S. The word “solbränna” means tan the color of the tea, did you get it?