John Elvin AstraZeneca

By John Elvin, Scientific External Liaison at MedImmune

There are several reasons why we chose a mechanical balance as the piece of equipment that is key to the Energy Challenge.

The most obvious one is that a balance is a useful tool in a whole range of scientific experiments. You can use the triple beam balance to weigh from a few grams to two and a half kilograms and, with the tare bar, also use various shaped containers to weigh fluids and powders as well as regular and irregular shaped solids. This flexibility allows investigation into the properties of matter and the combinations of ingredients in correct proportion for a recipe, as well as weighing different foods.

With a balance, you can answer questions such as: “How much does an apple weigh? Or a pencil? Or a smartphone? Or a whole host of other questions.

However, this would also have been possible with a digital balance.  The great thing about a mechanical balance is that it is obvious how it works. The weight on the pan must equal that of the movable weights on the three arms for the arm to be level and the smallest difference is magnified as a movement away from level.

In addition, the way the balance is set out in “hundreds” “tens” and “units” is very mathematical. You can demonstrate the concept of an equation with a balance. Whatever you do to one side of the fulcrum you must do to the other to keep the two sides equal.

A mechanical balance has a physicality about it. So much in science these days is digital or on a screen or virtual. The solid reality of the metal and the tactile nature combines sight, sound and touch to give a multi-sensory experience – linking the two human specialties of hands and brains. This gives a much stronger learning experience than just seeing figures on a digital screen.

And a final benefit is that, with a mechanical balance, there is no need to replace any batteries! Properly treated the balance should last a lifetime.

So, to conclude we chose a mechanical balance to encourage interest in STEM as it is in itself a great example of what the subjects of science, engineering, technology, and maths can produce as well as being a long-lasting multifunctional tool.