Tyler DeWitt

I hear a lot of instructors—particularly college professors—lamenting that American students don't have a fluency or an intuition for SI/"metric" units. True, but fluency and intuition can't simply be willed into existence. They are only the result of continual, deliberate, repetitive practice. Yes, SI is the "language" of science. But Spanish is the "language of Mexico," and we all know that a trip to Mexico doesn't make one a fluent Spanish speaker. Simply being exposed to a lot of something (metric units, foreign language, etc.) does not make someone proficient in it. Now, a good way to supercharge your Spanish learning would be to visit Mexico and do Spanish classes and have a Spanish tutor and spend your free time trying to listen, speak, and read as much as possible. But the roundtrip tickets to Mexico aren't enough. Similarly, if instructors want students to appreciate SI units, and to intuitively understand their magnitude, we must decide that is something we want to prioritize and we must practice, practice, practice. I recently saw an amazing SI unit activity from @APchemisMe, and I'm sure that many other instructors have similarly amazing content. But if it's a priority, it must be practiced. Over and over and over and over. It's the only way any of us have ever learned anything. #chemed #chemteach

“my teacher uses him [Tyler] to teach us while he [the teacher] sits on his phone.” Just got this comment today. The other day, I said “a teacher who can be replaced by a video should be.” I got some pushback from teachers who seem excellent, insightful, and dedicated. Just so there’s no confusion, it was teachers like the one mentioned in this comment that I was taking issue with. #chemed #chemteach

"My teacher loves your videos. We watch them in class every single day." No no no. Please. I cringe when I hear this. I didn't make science videos with the intention that teachers would play them during class. Class time is so precious. Time in front of your students is golden. Please think carefully before using it to show a video that students can watch at home. I think class time should be about asking and answering questions. It should be about solving problems and doing lots and lots of labs and collaborative activities. I don't think that "sit in a dark room and watch videos" is the most effective use of class time. Now look, I know there are certain situations when you want to show a video. Teachers get sick and exhausted sometimes, you have a sub, you need time to talk one-on-one with students and give feedback. OK, sure. Makes sense. But please, every single day should not be "watch YouTube video day." My videos (and I would argue all videos) should not be a substitute for teachers and teaching. I know this is harsh, and I'm gonna get some hate for it. But if a teacher can be replaced by a video, they should be. There are so many teachers out there who add so much value and do so many creative things in the classroom every day. Instructional videos should facilitate meaningful teaching interaction, not replace them. #chemteach #chemed

Controversial take (I'm excited to hear from those who disagree with me): putting 9th graders into a true AP Chemistry course as their *first* high school chemistry course is cruel and unusual punishment. I know this is very common at fancy private schools in metropolitan areas. They say their classes are rigorous because the students are so brilliant and can handle it. Trust me: they can't. They are just as lost as confused as any 9th grader, at any school anywhere. I used to be a soldier in the army of private tutors that supported these overwhelmed and completely lost 14 year-olds. In some schools, almost every single student in these classes has to have a private tutor, working multiple evenings a week to backfill an entire year of pre-AP chemistry while simultaneously re-teaching the college-level material that is going by at a screaming pace. I strongly believe that education should be challenging. But it should be doable. It should not require hours and hours every week from private tutors. It should be like a workout that builds students up from the ground, increasing the reps or the weight or the distance a little bit every day. Asking students to run a marathon with no prior running experience is "hard," sure, but it's not productive hard. It's just for show. (And yes, in case you're wondering, I did know ONE student would could handle such a class. She got a 5 as a 13 year-old with no private tutoring. It probably won't surprise anyone that she was in medical school before many students her age had started college. But suffice it to say, she was a bit of an outlier and not representative of most 9th graders, even those at fancy "elite" private schools.)

Way too many students make this mistake. Why do you think it is? When I sit down to tutor pretty much any chemistry student (high school, AP, intro college), I ask them to draw me water in its gaseous state. About 90% of the students draw some type of plasma situation, where all the oxygen and hydrogen atoms have ripped apart from each other. Now granted, these students have reached out for tutoring, so they are likely struggling. But I've also seen plenty of high-achieving students at selective universities make this mistake too. I wonder what it is in the curriculum and how we often teach it that cements this wildly common misconception. I'm really curious to hear everyone's thoughts. I have a suspicion that part of the fault lies in the introductory particle diagrams that depict solid, liquid, and gas phases. They tend to use individual particles (almost always depicted as glossy spheres) that fully come apart in the gas phase. I think it's really easy for students to see those diagrams and think that the particles always represent the individual atoms, and that atoms always come apart during state changes. It's an important (but really difficult) cognitive leap to understand that those high-level particle spheres may represent atoms, ions, or molecules depending on the compound that is depicted. Thoughts?!? #chemed #chemteach

Challenge: you want to determine if a student really understands the key concepts in chemistry, but you can only ask 3 questions, what would they be? Mine: 1) Explain the difference between how and why ionic and covalent bonds form. 2) You have 40 grams of carbon. Talk me through how you would figure out how many carbon atoms you have. No conversion factors or calculators, and we're not concerned with the calculation, it's the thought process. 3) Compare an aqueous solution of sodium chloride and sugar (glucose). Explain what they look like at the particle level, and how the two solutions are similar/different.

There are so many misconceptions and incorrect explanations about “suspensions” during introductory chemistry. The topic shows up a lot in high school and middle school chemistry (usually in comparison with solutions and colloids), but suspensions are usually not explained well, even/especially in textbooks. Way too often, “suspension” is incorrectly used to mean “heterogeneous mixture.” That’s how I learned it in middle school: that a solution is a uniform mixture (sugar in water), and a suspension is a non-uniform mixture (sand in water). And I still hear it explained that way all the time, by instructors, YouTube videos, etc. But that’s not quite right, and it’s missing important nuance. Sand in water is not always a suspension. It is always a heterogeneous mixture. But a suspension can be a “moment in the life” of a heterogeneous mixture. If you physically agitate a mixture of sand and water (e.g. stir or shake it), you can disperse the sand and water throughout each other, and that will temporarily create a suspension. Eventually, the suspension will settle out: the sand and water will separate into two phases. At that point, this mixture is a suspension no more, and it’s back to being a plain old heterogeneous mixture. Something that makes this even more tricky is that the technical definition (from IUPAC) of suspension is “a solid dispersed in a liquid.” But…plenty of resources use “suspension” to refer to liquid mixtures: not only, say, oil and water dispersed after agitation, but also oil and water sitting peacefully in two completely separate phases. Whether or not “suspension” should refer to mixed-up oil and water is probably a colloquial concern that doesn’t matter much. But, I think it’s fair to say that it doesn’t appropriately refer to oil and water unmixed and just sitting there. Since students often don’t have a good understanding of (temporary) suspensions, they’re really not set up well to understand colloids, which can be thought of as “permanent suspensions” that don’t settle out over time. Regardless, when we’re talking about mixtures, I think it’s important to first focus on homogeneous vs. heterogeneous (into which most mixtures can be classified), and then emphasize that suspensions are usually a temporary sub-category of heterogeneous mixtures. #chemed #chemchat #chemtwitter

If you teach #apchem, would you be interested in a textbook (and video series?) that students can actually understand, doesn’t contain the unnecessary technical stuff that isn’t tested, and would be a friendly resource for preparing for the exam?

I really wanted to help teachers and students review for the AP Chem exam. Check out these multiple choice practice problems and explanation video (youtu.be/Y4VPLuS0EhQ). I filled them with the kinds of tricks and traps that the test loves to use! #apchem #chemtalk #chemchat

I really wanted to help teachers and students review for the AP Chem exam. Check out these multiple choice practice problems (and explanation video). I filled them with the kinds of tricks and traps that the test loves to use! youtu.be/Y4VPLuS0EhQ #apchem #chemtalk #chemchat

May I introduce you to your new favorite band, Vansire. @wearevansire

I'm super excited to be making YouTube videos again. This one, on Aqueous Solutions and Solvation, is super colorful and (I think) very beautiful. More to come! youtu.be/AD22tefqhEQ