*This is a classic experiment that students enjoy at most ages, it is exothermic and in my experience is better to do with students over the age of 8 because the safety piece is key to being able to do experiments. While the leftover reactants are just soap, water and food colouring, the potential unreacted hydrogen peroxide can be irritating to skin (and worse if using 40 Volume or potassium iodide).*

Elephant toothpaste is an experiment that involves several mixtures, both homogenous and heterogeneous. This was nearing the end of our solutions unit, which allowed the students to connect abstract ideas in a concrete way.

To check understanding, at each step, I would ask the students, “heterogeneous or homogenous?” The students were able to say what they were thinking, and then justify their answers, this way I was able to tell if they were conflating homogenous and heterogenous (many were) but they knew exactly which one they were trying to explain. The water and yeast forms a heterogeneous mixture, the hydrogen peroxide, food colouring, and dish soap formed a homogenous mixture – the final product left in the bottle was homogenous, the soapy mixture outside of the bottle was heterogenous.

This activity was meant to take 15 minutes at most to be a quick reminder of mixtures and solutions, and allowing students to make hypotheses, observations, and conclusions.

Many students have seen this experiment (YouTube science is a really big thing in elementary schools), but they are intrigued to see how it will turn out for them and are excited to participate, learn, and most excitingly, share their ideas! Several students were willing to share what they know about this experiment, bringing to attention that this was exothermic, that yeast is alive, etc… It was super great to see all their knowledge!

Core Competency: Communicating

Facet: Focusing on intent and purpose

Profile: I can understand and share basic information about topics that are important to me, and answer simple, direct questions about my activities and experiences.

First Peoples Principles of Learning: Learning involves recognizing the consequences of one’s actions.

Big Ideas:

  • Solutions are homogenous (5)

Curricular Competency:

  • Make observations in familiar or unfamiliar contexts (5)

Content:

  • Solutions and solubility (5)