Question

Using which instrument, the consistency of lipstick is evaluated?

• A. \( \text{Cup \& bob viscometer} \)
• B. \( \text{Cone \& plate viscometer} \)
• C. \( \text{Ostwald viscometer} \)
• D. \( \text{Penetrometer} \)

Hint:

Think of "penetrate" – a penetrometer measures how easily something goes into the lipstick, indicating its firmness.

Answer 1

The Correct Option is D

The consistency and hardness of lipstick are typically evaluated using a penetrometer. A penetrometer measures the depth of penetration of a probe into the lipstick formulation under a specific load and time. This test provides a measure of the firmness or softness of the lipstick, which is crucial for its application properties and stability. Viscometers (cup & bob, cone & plate, Ostwald) are used to measure the viscosity of liquids, which is not the primary parameter for evaluating the consistency of a semi-solid product like lipstick.