Engineering, Science & Math in a Water Bottle

When I talk with young people about science and engineering I try to use everyday examples, but often come up with something too complicated, which leads to a lengthy, confusing explanation. This morning it came to me: Use an object young people would immediately recognize -- a bottle of water. So, how does that work in a discussion?

I start by explaining that the price of oil might require the bottle manufacturer to find ways to use less plastic or a different type of plastic. Engineers and materials scientists must examine many types of plastics appropriate as food packaging, test them, determine the proper thickness for a water bottle, and then design a new type of bottle that will withstand jostling in shipment and handling.

They also look at the plastic to ensure it does not make the water look colored. Colored bottles are fine, but a plastic that makes the water appear slightly yellow just won't sell. (Also, a bottle that uses less plastic might cost less to ship.)

Next, manufacturing engineers must decide on any modifications to the bottle-filling apparatus and make the required changes. The engineers and scientists who work with the new plastic formulations also want to ensure the type they choose can be easily recycled. No one wants the water bottles to go into landfills.

The increasing cost of plastics might also require a smaller bottle cap. Engineers must evaluate the types of plastics available and design a new cap. The new cap cannot require too much force to unscrew, or the person opening the bottle will squeeze it too hard and water will spill out. So the engineers who work on the cap must consult with the bottle designers to balance the need for a thinner bottle with the need for a sturdy but easy-to-remove -- and smaller -- cap.

Engineers must design the molds used to form the caps and ensure the packaging equipment can handle the smaller caps. If not, they must redesign some of the equipment and ensure it works properly. There's a lot of engineering, science, and math involved in all these steps.

Now, what about the water? Someone must determine how to filter the water, sterilize it if necessary, store it, and get it to the bottling equipment. Enter the chemical engineers and the biologists -- they work on this aspect of the process. Many people object to the lack of taste in pure water, so chemists formulate the proper amounts of minerals such as calcium chloride, sodium bicarbonate, and magnesium sulfate to add. The chemical engineers determine how to add these minerals in controlled amounts. Do they add them to each batch of water, or do the chemicals go into a continuous flow of water? Should they go in as solids or in a solution? How can the bottling company monitor how much of these chemicals actually go into the water?

Engineers answer these types of questions and design any needed equipment and procedures. Electrical engineers and instrumentation engineers set up the controls that move bottles through a production line.

Behind the scenes, scientists and lab technicians test bottles to make sure no plasticizers leach into the water and contaminate it. They might also file reports with local, state, and federal health bodies that monitor water quality and sanitary bottling conditions. And from time to time the lab people must test the water to determine that it meets quality requirements.

In practice, designing and filling a new type of water bottle might take less engineering work, but the descriptions above will help kids understand how science, math, and engineering influence their lives even through things that seem mundane. They probably never imagined the effort that goes into putting clean water in a bottle.

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