Which plastic is used for graduated cylinders and centrifuge tubes?

Which plastic is used for graduated cylinders and centrifuge tubes?

• A. Polycarbonate
• B. Polypropylene
• C. Polyethylene
• D. Polystyrene

Answer: (A)

The important idea here is choosing a plastic that is both transparent for accurate measurement and tough enough to withstand the demands of high-speed centrifugation and possible sterilization. Graduated cylinders need clear, easy-to-read markings and a smooth, scratch-resistant surface so the meniscus stays visible and the scale stays legible over time. Polycarbonate provides excellent optical clarity and high impact resistance, so a cylinder made of it remains readable and unlikely to crack if bumped. Centrifuge tubes must endure extreme speeds and, if needed, repeated sterilization; polycarbonate holds up to these stresses without cracking or deforming, maintaining integrity under high g and heat. That combination makes it a strong overall choice for both measurement devices and centrifuge tubes. In comparison, polypropylene is autoclavable and chemically resistant but not as clear or rigid; polyethylene is more flexible, and polystyrene is clear but more brittle and less suitable for repeated sterilization and high-speed use.

The important idea here is choosing a plastic that is both transparent for accurate measurement and tough enough to withstand the demands of high-speed centrifugation and possible sterilization. Graduated cylinders need clear, easy-to-read markings and a smooth, scratch-resistant surface so the meniscus stays visible and the scale stays legible over time. Polycarbonate provides excellent optical clarity and high impact resistance, so a cylinder made of it remains readable and unlikely to crack if bumped. Centrifuge tubes must endure extreme speeds and, if needed, repeated sterilization; polycarbonate holds up to these stresses without cracking or deforming, maintaining integrity under high g and heat. That combination makes it a strong overall choice for both measurement devices and centrifuge tubes. In comparison, polypropylene is autoclavable and chemically resistant but not as clear or rigid; polyethylene is more flexible, and polystyrene is clear but more brittle and less suitable for repeated sterilization and high-speed use.