Eight ways to demystify chemical engineering (Day 358)

This is probably the easiest way to demonstrate the power (if you’ll excuse the pun) of chemical engineering. So much of the work we do goes to provide electricity supplies for homes and business worldwide. Without chemical engineering, our lives would be much harder and a lot darker. Turn out the lights and challenge your audience to switch them on again without gas, oil, coal, nuclear or renewable power and a lot of chemical engineering.

Water is essential for life, and one the most important roles that chemical engineers undertake is to ensure that everyone has access to a clean water supply. In the UK, we are fortunate enough to obtain clean water at the turn of a tap; but this is not the case in many parts of the world. However, there are some simple steps you can take to demonstrate water purification at home to demonstrate what chemical engineers do on a grand scale. Follow this link for five ways to purify water (at your own risk).

This is the classic way to demonstrate fluid dynamics and particle size distribution, and I am sure that many of you have seen it done in science classes. Known as the 'muesli effect', shaking a box of breakfast cereal, like muesli, causes the large particles (eg nuts) move to the top of the box and the smaller particles (eg oat flakes) move to the bottom. This is a process called granular convection where larger particles 'float' on top of the smaller particles, which act like a liquid.

Under normal circumstance, water and oil don't mix. Unless you know how. Creating emulsions is important in chemical engineering, whether they are used in medicine, food products or cosmetics. You can easily demonstrate how an emulsion works to your friends with five things: water, vegetable oil, water-soluble food colouring, soap liquid and a small bottle. Ask your friends to add some water and food colouring to the bottle, with an equal amount of oil. Then get them to try to combine the two by shaking. When it doesn't work offer them our chemical engineering solution – the soap – which acts as an emulsifier. A few drops of soap will allow the two liquid to mix and form an emulsion.

Anyone who has tried to make a potato clock or lemon battery will recognise that making your own battery is a tricky process. But this is something that chemical engineers excel at. With the help of a voltage meter and an LED, there are a variety of ways you can use to impress your friends by making your own battery, for example, fizzy drinks, salt and even your own hands can be used to get a current flowing.

You can demonstrate how heat transfer works and create a tasty snack by making popcorn. There are three ways that heat can be transferred: conduction; convection; and radiation – and all of these can be used to pop corn. Conduction is heat transfer through matter, if you make popcorn in a pan, heat is transferred through direct contact, from pan, to oil, to kernel. Convection is heat transfer by the movement of mass from one place to another. In a popcorn popper the hot air transfers the heat to the cooler kernels, and when enough hot air heats the kernels they pop. Radiation transfers heat through waves, like in a microwave. So when you microwave popcorn the kernels heat up and pop as heat is radiated into them.

This method of explaining chemical engineering always goes down well. However, the concepts of fermentation and distillation are key in chemical engineering, whether used for brewing beer, producing drugs or separating crude oil into useful fractions. At home, distillation can be quite tricky and involves a lot of equipment, but fermentation can be done at a low-tech level with just four ingredients – malt, hops, water and yeast. The fermentation process can be as short as one day or last for months (it depends how soon you need to get your point across). Just remember to enjoy the fermenting process responsibly.