hands-on learning

If rhubarb stem is placed in a solution of permanganate, the purple permanganate ion is reduced to the colorless Mn²⁺ ion. It is thought that the oxalic acid present in rhubarb causes this reduction. The investigations presented in this post provide evidence that this may not be the whole story...

When describing abstract concepts like chemical bonding, it always seems to feel far too easy for both teachers and students to resort to the “wants” and “needs” of atoms. After all, we understand what it means to want, need, or like something, so it often feels appropriate (and easier) to use a relatable metaphor or subtly anthropomorphize these atoms to accommodate our students’ current reasoning abilities. While predicting the types of bonds that will form and the general idea behind how atoms bond can be answered correctly using such relatable phrases or ideas, the elephant in the room still in remains—do our students really understand why these atoms bond? 

Are you familiar with the dynamic density bottle experiment? This interesting experiment was invented by Lynn Higgins, and is sold by various science supply companies. Two immiscible liquids (usually salt water and isopropyl alcohol) and two different types of plastic pieces are contained within a dynamic density bottle. The plastic pieces display curious floating and sinking behavior when the bottle is shaken. 

The chemistry of the Sunflower dye found in McCormick’s Color from Nature food dyes is explored in this post. This is the last in a three-part series in which several experiments and demonstrations that can be done with Color from Nature food dyes are described.