# @stem_antics on Instagram

- **Type:** Video
- **Original URL:** https://www.instagram.com/p/DVWNzuCkaLt
- **Gondola URL:** https://gondola.cc/posts/61935804-stem-antics-instagram
- **Thumbnail:** https://img.gondola.cc/tr:w-,h-,fo-auto/postThumbnails/c41990c89a.jpg
- **Posted:** 2026-03-01T15:38:13.000+00:00
- **Account Owner:** Stem Antics (@stem_antics) — https://gondola.cc/stem_antics

## Caption

In a basic glucose solution, methylene blue acts as a reversible redox mediator. When dissolved oxygen is present (after shaking), methylene blue is oxidized and appears blue. As the solution sits, glucose reduces methylene blue to its leuco (colorless) form, consuming dissolved O₂ in the process. With less oxygen available, the dye stays reduced and the blue color fades.

At the same time, phenolphthalein reports the solution’s pH. In strongly basic conditions it is pink; when the effective basicity drops (as redox processes and dissolved CO₂ subtly shift the equilibrium), the pink can fade toward colorless. Shaking reintroduces oxygen, restoring the oxidized blue form of methylene blue and re-establishing conditions where phenolphthalein is visibly pink.

Net effect:
	•	Shake → oxygen in → methylene blue oxidized (blue), phenolphthalein pink in base
	•	Let stand → glucose reduces dye (colorless), oxygen depleted → color shifts back

Key chemistry concepts:
	•	Redox cycling (oxidation/reduction of a dye mediator)
	•	Dissolved gas equilibrium (O₂ exchange with air)
	•	Acid–base indicators and pH-dependent structural changes
	•	Reaction kinetics vs. mass transfer (mixing controls the rate)

This is a powerful demo of how chemical systems respond dynamically to their environment. What variable would you change first: glucose concentration, NaOH molarity, or temperature?

Share this with someone who thinks chemistry is just memorizing formulas. Follow for more mechanisms behind the visuals.
#STEMeducation #ChemistryDemo #RedoxReaction #AcidBase #ChemicalKinetics

## Stats

- **Views:** 230,447
- **Likes:** 77,236
- **Shares:** 0
- **Comments:** 151

## Tags

redoxreaction, stemeducation, chemistrydemo, chemicalkinetics, acidbase

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