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Leaving Cert Engineering: Plastics & the environment

How often Plastics & the environment comes up on the Engineering papers, every year it was asked, and questions to try.

HL Asked on 3 of the last 9 Higher Level papers, most recently in 2025.

OL Asked on 1 of the last 9 Ordinary Level papers, most recently in 2023.

June 2028 is the first exam on the new Engineering course. These come from the 2016–2025 papers, so read them as a guide.

Plastics & the environment, Higher Level(7 marks)

Quick ones on Plastics & the environment.

(a)Plastic made from plant starch such as maize that can be industrially composted?
  1. PVC
  2. PLA
  3. PTFE
(b)Plastic identified by resin code 1 in the recycling triangle?
  1. HDPE
  2. PVC
  3. PET
(c)Main environmental concern about microplastics?
  1. They persist and enter food chains
  2. They deplete the ozone layer
  3. They biodegrade too quickly
Show the answers

(a) PLA

(b) PET

(c) They persist and enter food chains

Your turn: Higher Level questions on Plastics & the environment.

Higher Level

Asked on 3 of the last 9 Higher Level papers, most recently in 2025.

Every paper, year by year

YearWhere it came up
2025Q1(f), Q7
2024Not asked
2023Q7
2022Not asked
2021Q7
2019Not asked
2018Not asked
2017Not asked
2016Not asked

Links open the State Examinations Commission’s paper for that year.

More Plastics & the environment questions

Plastics & the environment, 2 marks

Mechanical recycling of a thermoplastic involves?

  1. Burning it in an incinerator to recover energy
  2. Burying it in a lined landfill to stop leaching
  3. Shredding, washing and remelting into pellets
Show the answer

Shredding, washing and remelting into pellets

Sorted thermoplastic is shredded, washed and melted to make pellets for new products. Burning is energy recovery; landfill is disposal.

Ordinary Level

Asked on 1 of the last 9 Ordinary Level papers, most recently in 2023.

Every paper, year by year

YearWhere it came up
2025Not asked
2024Not asked
2023Q1(i)
2022Not asked
2021Not asked
2019Not asked
2018Not asked
2017Not asked
2016Not asked

Links open the State Examinations Commission’s paper for that year.

More Plastics & the environment questions

Plastics & the environment, 3 marks

Why are thermoplastics easier to recycle than thermosets?

  1. They rot away naturally
  2. They set permanently when heated
  3. They can be melted and re-moulded
Show the answer

They can be melted and re-moulded

Thermoplastics soften on reheating, so waste can be granulated and moulded again. Thermosets have cross-links that char rather than melt, so they cannot be remoulded.

Plastics & the environment, 2 marks

What is PLA?

  1. A metal alloy used for 3D printing
  2. A bioplastic made from plants like corn starch
  3. A plastic made only from crude oil and gas
Show the answer

A bioplastic made from plants like corn starch

PLA is widely used as 3D printing filament. It can compost in industrial conditions, but does not break down quickly in the sea or a garden heap.

Plastics & the environment, 3 marks

Why is plastic litter in the sea a long-term problem?

  1. It breaks down very slowly into microplastics
  2. It sinks at once and is buried under the sand
  3. It breaks down in weeks into harmless salts
Show the answer

It breaks down very slowly into microplastics

Most plastics are not biodegradable. Sunlight and waves break them into tiny pieces that fish and birds swallow. Reducing, reusing and recycling cut the waste.

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