1. Organisation: Lessons 2 &3 Food tests
Required practical – Use PURPLE BOOKS
Organisation: Lessons 2 &3 Food tests
LO: Use qualitative reagents to test for a range of carbohydrates, lipids and proteins. To include: Benedict’s test for sugars; iodine test for starch; Biuret reagent for protein.

2. Write up – in PURPLE BOOKS
Draw a diagram of the apparatus
Write a method
Identify Variables
Categoric variables have values that are labels, eg names of plants or types of material.
Continuous variables can have values (called a quantity) that can be given a magnitude either by counting (as in the case of the number of shrimp) or by measurement (eg light intensity, flow rate etc). Previously known as discrete variable.
Control variable is one which may, in addition to the independent variable, affect the outcome of the investigation and therefore has to be kept constant or at least monitored.
Dependent variable is the variable of which the value is measured for each and every change in the independent variable.
Independent variable is the variable for which values are changed or selected by the investigator.
Present and analyse results
Calculate rates of reaction using raw data and graphs.
Draw conclusions and give explanations for the results.