About Bret Norwood

Bret Norwood is a staff blogger for Learning Laboratory in addition to other roles, including UI design and content development for Study Putty, our free memorization tool for chemistry and many other course topics. He is also a published writer of literary fiction--see BretNorwood.com

Dimensional Analysis Made Easy

How much wood could a woodchuck chuck, if a woodchuck could chuck 557 kilograms per hour, in an eight hour work day. Give answer in megatonnes.

How much wood could a woodchuck chuck if a woodchuck could chuck 15.5 kilograms per minute in an eight hour work day? Give answer in megatonnes.

Dimensional analysis is not the first thing Mr. Spock does when the Starship Enterprise accidentally travels into a new universe or timeline. That is not what we’re here to learn about today.

Unfortunately. Because that sounds interesting.

Instead, we have what is also commonly called “the factor-label method” and simply “unit conversion.” Dimensional analysis is the method that is used to get an answer in the correct units of measurement in problems relating to math, chemistry, and other physical sciences. At its most simple, it can be solving how many minutes are in two hours, or, on the more complex end, it can be finding how many moles there are in three cubic meters of argon.

So are you stuck on your homework? We’ve assembled a few resources to help you with the factor label method. Continue reading

Teach Creatively! Reaching “Hard to Reach” Students

A C Bilbrew Public Library. Image from County of Los Angeles Public Libraries

A C Bilbrew Public Library. Image from County of Los Angeles Public Libraries

[Edit 4/14/14: If you came here looking for a blank multiplication grid, see this post for our PDF times tables.]

Three Free and Easy Ideas

During the 2007-08 school year I was a tutor with an agency serving the Los Angeles Unified School District under funding from No Child Left Behind (NCLB). A pre-test selected three California state standards that I was meant to enforce in each student, all of whom were unwilling and less than thrilled with school in general. I was on my own in terms of teaching materials and, feeling sorry for my bored kids and sensing the inefficacy of plain old worksheets, I found myself flexing my creative muscles to generate solutions, which I would like to share with any tutor or teacher who needs some inspiration. Continue reading

Happy Pi Day (and Contest Ends This Friday!)

The most evil eye chart in the world. "Now, can you read me the last line?" ... "AGHH! There is no last line!!" Image from Unihedron.

Pi Day is March 14. This is the most evil eye chart in the world. “Now, can you read me the last line?” … “AGHH! There is no last line!!” Image from Unihedron.

Did you know (3 syllables)

Pi, (1)

our fave constant, (4)

has (1)

its own holiday? (5)

Celebrate the interminable (9)

greatness (2)

with these Pi Day assets: (6)


Pi Day Dot Org Home (5)


Pi(ano) (3)

(Watch Pi as music) (5)


Search Pi for any number string (8)

(e.g. your phone number or birthday) (9)


Party hard for Pi–not too (7)

crazy, but irrational is fine.(9)


In other news (I’m done counting my syllables for the day), our Learning Game Idea Contest is coming to a wrap this week, and it’s not too late–procrastinators–to knock out that last minute Eureka-stroke-of-genius entry. The deadline is Friday the 15th. Motivational reminder: the prize is a $100 gift card to your choice of iTunes or Amazon.

A Free Online Toolkit for Math and Science Courses

Desmos Calculator, courtesy of Desmos.com.

Desmos Calculator, courtesy of Desmos.com.

We’ve assembled an online set of tools for use by a teacher or tutor looking for high quality free resources, or by a student who needs a little math, physics, or chemistry homework help. The following resources have been selected by our editors as representing the best of what is offered freely on the Internet. Continue reading

Threshold Concepts: Education as Rite of Passage

Initiates of ancient mystery religions would learn the meaning of symbols like this one. Image believed to be in the public domain; originally published 1896. From Wikipedia.

Initiates of ancient mystery religions would learn the meaning of symbols like this one. Image believed to be in the public domain; originally published 1896. From Wikipedia.

By dark of night the master leads you, the robed initiate, beyond the columns of the marble portico and into the candle-lit court of the temple. According to custom, the master has overseen your days of fasting, study, and preparation leading up to this, the day you would be ready to cross the threshold. Now, as the cock crows thrice, you are led into the place where you have never been allowed before, to see what you have never seen before, and to know what has been heretofore unknown…You enter into the inner portal of the holy of holies and behold, in the sacred light of a golden candelabrum… the solution to your chemistry homework.

A movement exists in education to view educational standards in the anthropological terms of the rite of passage. As elaborated by Victor Turner [Wikipedia] and other anthropologists, a rite of passage consists of an individual beginning in one social category, crossing a limen (Latin: threshold), and entering into another social category. Examples include rites of passage by which a boy becomes recognized as a man (e.g bar mitzvah), or by which a girl becomes a woman (e.g. bat mitzvah), or certain religious initiations, such as Greco-Roman mystery cults [Wikipedia] or, to use more familiar, contemporary examples, baptism, first communion, or confirmation.

The analogy is this: a student passes a conceptual limen when he or she comes to really understand any threshold concept. There is a metamorphosis from ignorant to understanding. Like a participant faced with the revelation of divine knowledge at Eleusis, the student confronts quadratic equations, the ideal gas law, the principles of engineering, the grammar of a well-composed sentence…whatever the concept, and that student is changed. Once a student masters a threshold concept, he or she doesn’t simply revert to ignorance. A threshold concept is of a class of concept such that it changes the student’s view of the course subject, and, perhaps, whether in a small way or in a profound way, the student’s entire worldview. Continue reading

Sig Fig Rules!–Master Your Significant Digits Here (A Learning Game Contest Example)

[Edit 09.05.13] SigFig is now accessible through our primary chemistry learning web app, Study Putty.

In the preceding weeks we launched our Learning Game Contest, seeking submissions of science/math learning game concepts and offering the prize of a $100 Amazon or iTunes gift card along with the chance of seeing that idea implemented in a playable game. With the intention of demonstrating the sort of concept we’re looking for, and to show how your concept could become a working game, we recently published Sig Fig Rules! online.

If you have ever taken a chemistry course, whether in high school or college, you may remember the lesson on significant digits. If your response to being asked to identify significant and insignificant digits was, like mine, “Discrimination! Who am I to tell a number his existence is insignificant?” you, like me, might have benefited from a learning tool such as this. Continue reading