Plastics Archives - Eva Varga

December 27, 2016

I grew up on the Oregon Coast in beautiful Bandon by the Sea. I spent many a day on the shoreline investigating the marine invertebrates under the rock crevices and walking the sandy beaches. My brothers and I longed for the minus tides, providing us the rare opportunity to go spelunking in the sea caves just off shore. These rocky islands are now protected areas for marine bird nesting habitat but back in the 70s, it was our playground.

dune geology tunicates
Dune geology features: foredune and deflation plain

Tracking Marine Debris

In all the years I have spent on the beach, I have found a diverse amount of debris and organisms in varying states of decay. I probably spend an equal amount of time sifting through the wrack on the high tide line as I do in wave zone digging in the sand looking for mole crabs.

I have found marine debris from Japan evidenced by the kanji script. An occasional flip flop or fishing net remnants are not uncommon. While immersing myself in marine biology courses at the Oregon Institute of Marine Biology one summer, I even found several squid egg cases that washed ashore after a winter storm, providing my peers and I an opportunity to observe the development up close. Yet, once in a while, I am still surprised at what washes ashore.

Walking along the ATV trail across the deflation plain

This past holiday weekend, my family and I enjoyed a leisurely walk on the beach near our home. Our goal was to field test a new marine debris app, a joint initiative between the NOAA Marine Debris Program and the Southeast Atlantic Marine Debris Initiative. The tracker app allows you to help make a difference by checking in when you find trash on our coastlines and waterways.*

We drove out to the North Spit and thereafter began our excursion through the deflation plain. We soon discovered, however, that there was too much standing water to stick to the trail that meandered through the wetland area. We thus walked along the ATV road until we reached the small foredune. Just a few feet up and over and we arrived on the sandy beach.

No sooner did we arrive at the shore and we immediately were captivated by the presence of a strange organic material that was strewn across the beach for miles. Upon first glance, it looked like a hard plastic tube resembling a sea cucumber. My first suspicion turned out to be incorrect, however. Upon returning home, I learned that what we had found were actually colonial tunicates. Fascinating!

tunicates rare creatures
Planktonic salps, Pyrosoma atlanticum, strewn across the beach.

What are Tunicates?

This bizarre and rarely-seen creature is called a pyrosome, a species of pelagic colonial tunicates. Their scientific name, Pyrosoma atlanticum, is derived from the Greek words pyro meaning ‘fire’ and soma meaning ‘body’ which refers to the fact that they are known for bright displays of bioluminescence.

Pyrosoma atlanticum are one of the few pyrosomes that make it to the west coast of the U.S. The species found here are less than a foot but can get as long as 24 inches. Largely colorless, they can show up as pink, grayish or purple-green.

tunicates invertebrates
A specimen of the colonial tunicate, Pyrosoma atlanticum 

These massive colonies of cloned creatures are related to a kind of jellyfish called a slap. A tunicate is a marine invertebrate animal, a member of the subphylum Tunicata, which is part of the Chordata, a phylum which includes all animals with dorsal nerve cords and notochords.

Each individual organism is about 1 cm long – less than a third of an inch. They are all connected by tissue and in turn form this colony that looks like a plastic tube. The recent winter storms have caused them to strand on the shores and have been found in all areas of the coast.

Usually found in temperate waters as low as 800 meters. The colony of animals is comprised of thousands of individual zooids and moves through the water column by the means of cilia (an organelle found in eukaryotic cells that project from the much larger cell body).

As they move through the water column, sometimes close to the surface and sometimes as far down as 2600 feet, they filter plankton out of the water for food. As it sucks water in, it then pushes it back out, thereby propelling it through the ocean. It does all this via one opening only, so it moves incredibly slow.

For more images of Pyrosoma, check out Bob Perry’s photographs. Included in his work are a few pseudoconchs (false shells) of the pelagic mollusk Corolla which we similarly found.zoologyIf you are interested in learning more about invertebrates with your students, I encourage you to look into the Amazing Animals curriculum unit I have written to introduce middle level students to zoology. This 10-week unit is full of inquiry-based activities and lesson plans fully outlined for you.

Due to our fascination with these rare creatures, we didn’t spend as much time with the debris tracking app as I had intended. We’ll give it a go another time.

March 25, 20161

bio plasticsPlastics play an important role in our lives.  Plastics are used to manufacture many everyday items and have significantly reduced the use of glass.  Some plastics are very durable and make things like furniture and appliances.  Other plastics make items such as diapers, trash bags, cups, utensils and medical devices.  The largest amount of plastic is used to make containers and packaging for items such as soft drink bottles, lids, shampoo bottles, etc. Common plastic is made from petroleum, a fossil fuel which is nonrenewable.

Nonrenewable resources are made naturally by the earth, but do not renew themselves fast enough to be able to count on having the resource for an indefinite period time.  Some resources are considered non-renewable because our access to the resource is limited.  For example, glass and metal are non-renewable resources.  The elements and minerals used to make glass and metal are found in the structure of the earth’s crust, however we are limited to what we can access through mining.

Renewable resources are either naturally reproduced at a sustainable rate or they can be produced in agriculture at a rate equivalent to the demand or need.  For example, corn can be used for ethanol fuel and to produce corn oil.  Corn is a renewable resource.

DIYBioPlasticsBioplastics are a type of plastic made from renewable, biological materials like starches, cellulose, oils or proteins. They generally contain little to no petroleum and therefore are usually biodegradable. When bioplastics are exposed to the environment (sunlight, heat, water, microorganisms) they breakdown into non-toxic compounds like carbon dioxide and water. Additionally, unlike petroleum-based plastics, bioplastics are made from renewable resources. These resources are typically agricultural byproducts, like cornstarch and potato starch, tapioca starch and casein (milk protein).

Biodegradable: refers to material capable of breaking down into harmless products through the action of living organisms or natural processes

Byproducts: in agriculture refers to secondary products created from a crop. For example, corn starch is a byproduct of corn

Make Your Own BioPlastics


  • Plant based oils (Corn Oil, Sesame Oil, Vegetable Oil)
  • Cornstarch
  • Water
  • Food coloring
  • Measuring spoons
  • Eyedropper (optional)
  • 1 Ziploc bag per student
  • Access to a microwave oven


  1. Place the following ingredients in a plastic bag: 1 tablespoon of cornstarch, 2 drops of oil, 1 tablespoon of water, and 2 drops of food coloring.
  2. Seal the bag and gently mix the cornstarch mixture by rubbing the outside of the bag with your fingers until combined.
  3. Open the bag slightly, making sure it can vent. Place the bag in a microwave oven on high for 20-25 seconds.
  4. Carefully remove the bag from the microwave and let it cool for a few minutes. While it is still warm, students can try to form their plastic into a ball. Observe what it does.
  5. Ask them to describe their plastic; did it turn out differently than others? Does the type of oil you used affect the bioplastic? Have the students name three things they could make with bioplastic.

Take it Further

I’m committed to sharing activities and resources for teaching science in your homeschool. I believe it is helpful to see that science isn’t scary and it doesn’t require special curriculum. Here are a few resources that you can use to further your study of plastics and renewable vs. nonrenewable resources.

Watch the 3-minute How Stuff Works video clip about Corn Plastic.

In this hands-on, inquiry based Plastics Lab Activity, students investigate whether all plastics the same? How are they different?

Polymers Are Cool ~ Experiment with different polymers, large molecules composed of many repeated subunits, with these 3 great recipes.

As plastics are not biodegradable, learn how you can make a difference in encouraging others to reduce our use of plastics. The volunteers at Washed Ashore inspired us to create a Bottle Cap Mural to help spread the word of the harm done to our oceans by plastics.


February 19, 20144

Plastics are everywhere – from airplanes to drinking bottles to sports equipment. They are most commonly derived from petrochemicals but many are partially natural.  Typically, plastics are organic polymers (or chains of carbon atoms with hydrogens hanging off), but they often contain other substances.

Each plastic is chemically unique and has distinct properties that make it suitable for certain products. These different characteristics (weight, durability, stacking, and even consumer appeal) are taken into consideration when packaging is considered for new products.

plastics lab activityPlastics Lab Activity

Plastics can provide hands-on, inquiry based lab activities with which students can investigate materials that are common to your everyday lives. To begin our initial plastics lab activity, I asked the kids to name as many things as they could that are made of plastic. Are all plastics the same? How are they different?

I then displayed a number of plastic materials I had collected and we talked about the characteristics of each. [Alternatively, you could do this lesson in two parts and ask the students to bring in samples themselves.]

resin codes

I explained that plastics are classified #1 through #7 and I showed them how to check the bottom of the object to locate the number inside the recycle symbol. Even though some recycling centers only accept certain numbers, all plastics with this symbol are recyclable. Markets just don’t exist for all recycled products.

After our discussion, students were asked to sort the plastic bottles and containers according to their numbers. Then, students were asked to brainstorm different physical properties that are characteristic of each type of plastic and test them.  The students were encouraged to make a table in their science notebook and record the physical properties of each type of plastic.  This data table would then be used to help them classify a set of unknown plastic pieces

  • Density – Does the plastic float or sink in water? (Cut plastics into pieces before dunking in water. #2, #4, and #5 float while #1 and #6 sink.)
  • Transparency – Is the plastic clear or opaque?
  • Luster – Is the plastic dull or shiny?
  • Brittleness – Does the plastic break when bent?
  • Rigidness – Is the plastic flexible or tough?
  • Color – Is the color the same for every sample number?

Mystery Plastics

In advance, samples of #1, #2, #3, #4, #5, and #6 plastics were cut into small pieces (about 1 to 2 in.). As many were not distinguishable by sight, I cut each number into a different shape. For example, I cut #1 plastic into squares, #2 into triangles, and so on.  I made a key that identified each plastic by its number. A mixture of all types of plastics were then placed into a bag for each group. 

When the students’  data tables were complete, I gave a bag of mystery plastics to each group and challenged the kids to identify the different plastics by their physical properties. Could they assign a number to each sample? Once a group was finished, they could check their predictions with the key.

Take it Further

During the testing process, one of the students made an interesting discovery in class – he had pulled on a strip of plastic cut from a bread bag and discovered it stretched quite a distance before breaking.  Another plastic (a sandwich zip baggie) took significantly more force before breaking.  This lead us to talk a little about tensile strength.

I encouraged the kids to pursue this further by cutting strips (approximately 2.5cm by 12cm) from a variety of different plastics (freezer bags, food wrap, microwave wrap, trash bags, grocery bags, or any other type of similar plastic) and developing a test to determine the weight needed to break each of the plastic strips. As you slowly pull the ends apart (stress), you can feel the resistance of the material as you pull it (strain).

Note: If you choose to pursue this, be certain to cut out plastic strips that are consistent in size and either parallel or perpendicular to the grain of the material.  [By holding the bag to the light, the lines you see indicate the general direction of the polymer chains. The direction in which these chains are lined up is also known as the anisotropic nature of the material, or the direction of extrusion.]