Lab 9 – Food Packaging and Polymers
Objective
The objective of this lab is to explore how food is packaged, why food is packaged and how this may affect our
environment.
Background
There are many ways food is packaged; plastic bags, plastic bottles, glass jars, cardboard boxes to name a few. The
reasons food is packaged are many. The obvious reason is to keep the food sanitary and to help preserve it, to keep the
food from undergoing undesirable chemical changes (spoiling) and physical changes (flat soda, crushed food). However,
it also serves as a marketing tool.
The type of packing that is used is important depending on what the food is. For example, you probably wouldn’t want
ice cream in a metal container, because it would be too cold for the consumer to hold. Some things need to be able to
be resealed, such as soda bottles. Some things need to be airtight to keep oxygen and humidity out.
The food industry would also like to use packaging that is cheap to make and to transport. Plastic is used a lot for this
reason. Plastic is made from fossil fuels. Did you know that? Plastic is a polymer and the starting material is oftentimes
ethylene, which comes from fossil fuels. There are also other things added to change the properties of the plastic, such
as bisphenol-A, which makes plastic hard or phthalates, which make plastic more flexible. Can you think of reasons that
this might an issue as far as our environment is concerned?
What is a polymer? Polymers are substances whose molecules have high molar masses, macromolecules (really big
molecules). They are made up of a large number of repeating units called monomers (many times this is the ethylene).
Monomers are tiny molecules that can join together to form a long chain, resulting in a polymer. These monomers can
