Activity 1: simple flower perfume You will need: * a container with 100ml water; * a cotton square; * enough chopped flower blossoms to fill the container.
This is what you do: * place the chopped flowers in the fabric; * completely immerse in water and leave overnight; * remove fabric and flowers, squeezing the liquid into a heatproof dish; * simmer gently to concentrate the perfume, continuing until about 10ml of liquid remains.
Extension activity Try a 50:50 mixture of water and alcohol in place of water alone. Avoid flames since both liquid and vapour are flammable.
Activity 2: essential oils by steam distillation You will need: 30g grated lemon or orange peel; la steam-generator fitted with a safety valve; * a small flask, about 100ml; * a condenser or a long tube that can be cooled.
This is what you do: * place the peel and 40ml water in the flask; * connect the flask to the steam generator on one side and the condenser on the other; * heat the flask until the water boils; * blow steam through the flask and collect the distillate; * the distillate will contain oily drops and water.
Most essential oils are lighter than water. The densities of lemon and orange peel oils are the same, about 0.85gml.
Activity 3: the ribbon of Bruges = This experiment produces a slow-burning fragrant tape, rather like the fuse of a firework. It requires very close supervision.
You will need: a strip of cotton or blotting paper 1cm wide; * a concentrated solution of potassium nitrate (NB: consult safety advice on handling this material); * essential oil from Activity 2 or a similar fragrant material; * an empty jam jar.
This is what you do: * soak the tape in the potassium nitrate solution and leave to dry; do not heat it (flammable); * when dry, spread a little of the essential oil along the tape; * when dry, drape the tape over the edge of the jar; * ignite the end and blow out the flame, leaving it to smoulder, the effect is like an incense stick.
Activity 4: perfume diffusion The strong smells of perfumes make them ideal to monitor the rate of diffusion in air. You can use any strongly scented material, perfumes, after-shave or air-freshener blocks. Ask students to devise ways to measure the rate of spread (diffusion) of the smell across a room or hall. Can it be done using a wide tube, such as a plastic drainpipe?
Activity 5: staying power As a home-based exercise, students can monitor the persistence of smell of a perfume over a complete day. They could compare: * oil-based perfumes; * water-based colognes; * alcohol-based after-shave; * solid stick perfumes such as some air fresheners.
The perfume material can be spread on a cloth and the strength of smell tested at regular intervals.
Websites These are a few of the thousands of sites about perfume: www.pioneerthinking.com
www.experimentarium.dk www.science.caaskascientist www.essentialoils.co.zaextraction_methods.htm