How does a natural resource become a useful synthetic material?
Submit: An evidence record, explanation and revision.
Related lesson: Chemical Reactions
This is a teacher-led extension beyond the short lesson. The task supplies a performance opportunity; completion alone does not certify mastery, full NGSS coverage or state alignment.
Teacher review guideBuild the idea
Ethane can be separated from natural gas liquids and processed to make ethylene. Polymerization joins ethylene building blocks into polyethylene with different properties. A chemical process changes molecular structure; shaping an existing plastic is a separate physical operation. U.S. plastic feedstocks include natural gas processing products and petroleum refining products; crude oil is not the only starting point.
Science / engineering practice
Obtaining, evaluating and communicating informationCore idea
Synthetic materials arise from chemical processing of natural resourcesCrosscutting concept
Structure and functionEvidence and model inputs
Source cards: EIA identifies ethane as a feedstock for ethylene and plastics. Its plastics FAQ explains feedstock sources and limits of national consumption estimates. A classroom molecular sketch represents ethylene units joining a chain; it is a conceptual model, not an industrial operating procedure.
Keep actual observations, published findings and invented model cases labeled separately. If a source or required equipment is unavailable, pause that part with a teacher; do not invent results.
Materials and preparation
Paper, graph paper or spreadsheet, and the linked readings.
Grade-level scope
Use qualitative molecular models. Industrial reaction details and unsafe synthesis are not required.
Do the work
- Read both EIA sources and record one supported fact and one limitation from each.
- Draw resource → separation → chemical processing → polyethylene → product. Distinguish chemical conversion from molding.
- Compare a reusable polyethylene container with a disposable use: identify a useful property, resource demand and waste concern.
- Write an explanation connecting changed molecular structure with new material properties and a societal benefit/tradeoff.
- Revise any claim that all plastics have the same origin, properties or recycling pathway.
Learner worksheet
Write on paper or type here and print. Entries stay in this page’s memory and are lost when you leave or reload; they are not saved or submitted.
Check your reasoning
- Does molding alone make a new polymer?
- Is all plastic made directly from crude oil?
- Does durability have only benefits?
- Can these sources give an exact petroleum amount for every plastic?
Teacher review guide
Review the actual deliverable and discuss the reasoning. For each criterion, use 0 when evidence is absent or fundamentally incorrect, 1 when partly supported with a material error or omission, and 2 when accurate, supported and complete for the stated task. Maximum 8 points is a task score, not a proficiency certification. Give feedback and allow revision.
- Traces a named material to natural feedstocks.
- Explains a chemical conversion, not only a shape change.
- Synthesizes two sources and notes a data limitation.
- Connects properties with a supported benefit and societal concern.
Answer guidance for the reasoning checks
Does molding alone make a new polymer?
No; molding changes shape. Polymer synthesis changes molecular structure.
Is all plastic made directly from crude oil?
No. Feedstock routes vary; natural gas liquids are important.
Does durability have only benefits?
No. It is useful in service but can make discarded material persist.
Can these sources give an exact petroleum amount for every plastic?
No. The EIA FAQ explicitly describes data limitations.
Access, support and extension
Offer read-aloud support, labeled diagrams, larger print or an oral/recorded explanation while preserving the scientific reasoning. A partner or teacher can handle physical manipulation while the learner plans, records and interprets. Use a teacher-provided measured dataset only when its provenance and limitations are explicit; it does not replace conducting an investigation when that is the assessed practice. For greater independence, remove prompts and ask learners to compare a second explanation or test another justified revision.
Sources and standard reference
- Official NGSS MS-PS1-3 performance expectation — inspect the practice, core idea, crosscutting concept and assessment boundary.
- EIA plastics FAQ
- EIA ethane and ethylene
Instructional text and hypothetical cases are original. Linked source readings supply published evidence where specified. Teachers should judge fit with their course and state requirements.