Mentos and Diet Coke Geysers II

In the interest of advancing the pursuit of scientific truth I will report on the results from the Mentos and Diet Coke investigation that I described in the last post. As I said our  control conditions were 24 oz. (700 milliliters) of Diet Coke with 5  mint Mentos introduced through a “geyser tube.” The average [...]

Mentos and Diet Coke Geysers

The final week of lab this semester we did an experiment based on the Mentos and Diet Coke geyser phenomenon. I bought several “geyser tubes” from Steve Spangler which allow the operator to introduce 1 to 10 Mentos (or Mentos-shaped objects) into the soda bottle in a safe and reproducible fashion. There is not a [...]

Antioxidant Activity III

The second week of the antioxidant lab students analyzed the antioxidant power and polyphenol content of four commercial bottled teas. We used TPTZ (2,4,6-tripyridyl-s-triazine) FRAP assay to measure antioxidant power of tea and compare it with a gallic acid standard. We used the same serial dilution technique that we had performed the previous week. The [...]

Antioxidant Activity II

We did a series of two experiments on antioxidants in the Introduction to Organic Chemistry laboratory this spring. We chose to use TPTZ (2,4,6-tripyridyl-s-triazine) as our indicator in the ferric reducing antioxidant power (FRAP) assay. As far as I could tell the original article for this assay is a 1996 Analytical Chemistry paper by Benzie [...]

Antioxidant Activity I

We did a series of two experiments on antioxidants in the Introduction to Organic Chemistry laboratory this spring. I have seen antioxidant experiments in JCE and I performed one during the CASPiE Workshop a couple of years ago that has been reported in JCE by Burgess. So I have had this on my radar for [...]

The Shape of Analysis Part II

This is a second post referring to the “extraction of caffeine from tea” and “extraction of caffeine from beverages” that we did this spring in the introduction to organic chemistry course. On the first “tea” report, I had the students consider a series of HPLC chromatograms that paralleled the previously described UV traces. I presented 1) [...]

The Shape of Analysis Part I

We did the “extraction of caffeine from tea” and “extraction of caffeine from beverages” this spring in the introduction to chemistry course. The caffeine extraction lab is one of my standard experiments and seems to be adaptable to different levels of students. For the analysis of the students’ extracted caffeine we did TLC which is [...]

The Hand is Smarter than the Eye

This past week we did the stereochemistry modeling activity during the lab period. This time it worked out that the activity was scheduled after the first class period on stereochemistry. I like the students to make the connection between models and drawn stereochemistry dashed-wedged representations as earlier as possible. The idea, in my mind, is [...]

Clamps! Or a Clamp-like Device

This week we distilled ethanol from the fermented rice/corn/potato mash that we prepared the week before. The main challenge in distillations is the complex set up involving many pieces of glassware and apparatus. Clamping glassware and various objects to a ring stand or ring stands can be quite and ordeal. The first issue is: 1) [...]

Sliding Down the Slippery Soap

Our fourth experiment of the year in introduction to organic chemistry was making soap. This is a fun and practical experiment that involves some good chemical principles. The students could vary the composition of their soap by mixing lard or vegetable shortening with olive, corn, or coconut oil. For each combination the appropriate amount of [...]