Most students encounter the idea of rate when exploring the rate of dissolving in simple practical activities. They invariably use a clock of some description, and make observations regarding 'disappearance' of material. It enables the collection of data and allows pupils to demonstrate a quantitative as well as a qualitative approach to this practical activity.
In a typical experiment like this students may be given two types of sugar and asked to see which dissolves the quicker.
The judgement is made on the basis of the completion of dissolving. To some this may suggest we're looking at how far the change has gone rather than how fast.
After working through this topic you will be able to:
- reflect on the differences between rate and the progress of a chemical reaction;
- develop activities to support student understanding of what is meant by rate;
- explore some of the data handling aspects of recording the rate of reaction; and
- consider the challenges experienced by students during practical activities.