Big Ideas Of Science
Average Learning Time
This Inquiry Learning Space is designed for young Chemistry students of lower secondary school (12-15 years old) and aims at introducing the pH concept and scale.
It is based on a pHET simulation which is simple to use and involves the characterisation of familiar solutions into acids or bases. Furthermore, it studies the effect of volume and dilution to the pH of a solution.
The benefit of conducting this lab virtually is that students can test liquids that are normally difficult to test in “real” labs, such as vomit and blood. It is also easy and quick to use and overcomes practical problems such as pH-meter calibration, need of multiple instruments and resources, lack of time and other educational difficulties, whilst at the same time offering a fun and informative introduction to the pH scale.
During this activity the students are able to conduct three different experiments:
Experiment 1: pH measurement the pH of 11 familiar liquids and classification into acids or bases
In this experiment students “test” the pH of 11 different liquids from their everyday life, such as blood, spit, soda pop, battery acid and water, though the use of an electronic pH-meter, which they are supposed to classify into acids or bases. Through this activity they are also included to neutral solutions.
Experiment 2: Influence of volume to the pH.
In this phase the students test whether volume has an effect on a liquid’s pH.
Experiment 3: Influence of dilution to the pH.
In this experiment students test whether dilution (the addition of water) affects a liquid’s pH and note the difference between an acid and a base, as in both cases the pH approaches 7 (in the case of an acid in increases, whilst in the case of a base it decreases).
Throughout the activity the students are required to answer a number of questions that require critical thinking and link the concept of pH to real life (e.g. why does drinking soda pop help soothe a tummy ache).
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