This investigation looks at rates of reaction by using the reaction between oxalic acid in the rhubarb and potassium Manganate VII.

As described, the investigation looks at concentration and surface area but temperature would be an easy addition.

Rhubarb! Rhubarb (demonstration version)

Rhubarb Rhubarb – Experiment Guide

Rhubarb Rhubarb – Teacher’s Guide

Rhubarb Rhubarb – Technician’s Guide

Rhubarb Rhubarb – Risk Assessment

Rhubarb Rhubarb – Discussion Activity

Rhubarb Rhubarb – Introductory powerpoint

Image by Dieter Weber – Used under a Creative Commons License CC BY-SA 3.0