Todd Hollis

Physical science students are studying concave and convex mirrors and lenses today.

A simulation of a grain elevator explosion. The fire is created when air is pumped into the 'elevator,' blowing lycopodium powder (like grain dust) into the air. There is a lit candle in the can. Scale this up = big problem.

Random student question: "Mr. Hollis, could you die from eating too many cough drops?" We used Merck to look up LD50rats menthol. Rats are not humans, but gives us approximation. It would take 200ish bags in one sitting to reach LD50 for a 100kg 'person.' I think we are safe.

Today we perform an experiment to determine the amount of carbon dioxide produced when wood (glucose) burns. We will scale our results up to predict the amount produced when an acre of forest burns.

Last week Chemistry students saw magnesium burn. Absolutely white hot at 3100C (5100F). Today, we burned steel wool, which is mostly iron. A much slower, cooler burn. 1000C (1800F). We used this reaction to discuss limiting and excess reactants.

It’s in the mid-50s in central Illinois in February. A perfect day to get outside and podcast walk. How is light produced in glow sticks? How does sunscreen work? How do sunglasses work? @ChemForYourLife will tell us. We will jigsaw what we learned next time.

Stoichiometry and peer coaching today.

Today we went back to 1666 and replicated Isaac Newton's experiment that discovered that white light is made up of the spectrum of visible light. This led to Herschel discovering IR in 1800, and Fraunhofer identifying spectral lines in 1814.

Solutions containing two weak acids are 'dominated' by one of them. The dominant acid is determined by comparing the acid dissociation constants, Ka. In this case, nitrous acid, HNO2, dominates hydrocyanic acid, HCN. We calculated the concentration of all species in the solution.

When there is adequate fuel, oxygen, and heat, the conditions for fire are met, see the fire triangle. Here, lycopodium powder demonstrates extreme flammability WHEN PARTICLES ARE ADEQUATELY SPREAD OUT. This reaction is similar to what can happen in a grain elevator explosion.

Today we are standardizing sodium hydroxide, NaOH, with potassium hydrogen phthalate. The standardized NaOH will be used to determine the citric acid concentration in 7-Up and Sprite. Structure credit: PubChem

I have a really cool job.

Whenever I need a periodic table to share from students, I inevitably end up at @WUWMradio site and this periodic table and Dr. Bassam Shakhashiri's discussion. Great stuff. wuwm.com/podcast/lake-e…

Because I heard an influencer use the "I can't even pronounce this. What the heck is ribovlavin and why is it in our food" arguement last week, today I am going to teach my students what the IUPAC chemical name of Vitamin B2 is. By the way, you need it and it's safe.

I went through this thread today with my chemistry classes. While I agree (believe) much of this, it was interesting to discuss some of the red flags I saw. Mostly, statements that were definitive, but lacked evidence or were incorrect. And the link at the end to buy the book.

After kicking the semester off with acid/base review, seniors are doing an article jigsaw. How can warmer environments skew reptile sex ratios? Can we fight cancer through cellular therapy? Are there possible positive health effects of hypoxia - low oxygen environments?

Advanced Chemistry students are determine the molarity of acetic acid in Clover Valley vinegar. Titration using standardized sodium hydroxide. A little quality control check of product labeling.

Studying collective properties. Determining water's boiling point elevation due to addition of calcium chloride. Conversely, it also lowers the freezing point.

Saturated, supersaturated, and ORNAMENTS! Sodium borate (borax) crystals.

Chemistry students are conducting flame tests on salts of various metals today. How do they make fireworks so colorful? Now we know! Lithium, copper (II), and sodium ions are shown.