This Unilever Laboratory Experiment, published in 1970, describes the procedure for a titration with EDTA and Eriochrome Black T to determine the total hardness of water. The details cover the preparation of a standard solution of EDTA as well as the steps of the titration.

As the number of cells in a microbial culture increases, turbidity increases. In this experiment students calculate doubling time and growth rate constant using absorbance as the measure of growth. Turbidity is caused by suspended cells in the growth medium scattering light, and may be measured using a colorimeter...

This experiment is a continuation of Determining Doubling Time. Students create a standard curve of absorbance against yeast concentration, and use this to determine the concentration of yeast produced over time.

The standard curve (dry mass, grams per litre) is generated from known concentrations of dried...

This mystery deals with a laboratory report in which the written results suddenly vanished. The students need to find out how the writing vanished,  how to recover the vanished data, and what the secret of the pen is.

Curriculum links include ...

The work suggested in this Nuffield Working with Science unit encourages the students to start thinking about efficiency by presenting them with some problems which are a familiar part of their daily lives. They are asked to investigate problems which have been chosen...

This Nuffield Working with Science unit aimed to enable students to design circuits to meet specific needs. The plan was also to help students to realise the range of electronics problems which they can solve by taking a systems approach.

This Nuffield Working with Science unit was designed to introduce students to the concept of Britain's impending 'energy gap', how it will occur, and what we might do to bridge it. The unit features a substantial decision-making element.

From the Institute of Physics, this learning episode shows that charge carriers in good conductors usually move very slowly. It illustrates the derivation and use of the equation I = nAvq.

A range of activities include:
• viewing the movement of permanganate ions in an electric field
•...

This activity from the Institute of Physics discusses energy transfer in electric circuits and links this, by analogy, to other more familiar examples.

The activities include:
• demonstrations of human and lemon-powered batteries to illustrate that that there is nothing special about the chemical...

This series of activities, from the Institute of Physics, help student to understand electrical resistance. What is resistance, how it can be measured, how it arises and what affects it? During the topic, resistance is related to current, voltage, type of material, temperature and light intensity. The electrical...

From the Institute of Physics, this learning episode provides a quantitative definition for resistance (R = V / I) which reinforces the qualitative notion that more resistance means less current. It looks at Ohm’s law, describing that this is not the same thing as the definition of resistance.

Activities...

Produced by the Institute of Physics, in this practical investigation students measure the current and voltage characteristics for several components and identify ohmic and non-ohmic behaviour. Students determine the V-I characteristics for: • a carbon resistor • semiconductor diode • a filament lamp In addition,...

In this learning episode, from the Institute of Physics, students derive the equation relating electromotive force (emf), terminal potential difference, current and internal resistance. They then tackle questions about the internal resistance of a power supply.

This demonstration or student practical activity, from the Institute of Physics, helps students learn to use an oscilloscope to measure voltages. It helps students to understand the use of a cathode ray oscilloscope by showing:
• how the oscilloscope plots a graph...

Produced by the Institute of Physics, this learning episode helps students to distinguish alternating from direct currents before revising why alternating current (ac) is so important.

The range of activities include...