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Why do white things turn yellow if they stay in light?

Sarah Jenkins
Sarah Jenkins
Lead Content Curator · Mar 25, 2026 · Updated Apr 13, 2026

It's not that they're white, it's that they're made of a type of plastic that, after prolong exposure to light, will degrade, becoming yellowed and brittle. UV is bad for that type of plastic, so the more time it spends in direct sunlight, the more it yellows.

47
Words

1 min
Read Time

#324
of 500 in Science

-35%
vs Category Avg

The Short Answer

It's not that they're white, it's that they're made of a type of plastic that, after prolong exposure to light, will degrade, becoming yellowed and brittle. UV is bad for that type of plastic, so the more time it spends in direct sunlight, the more it yellows.

Analysis

Key Concepts: It's, they're, type

This explanation focuses on it's, they're, type and spans 47 words across 2 sentences. At 35% below the average Science explanation (72 words), the answer takes a direct, no-frills approach — sometimes the simplest explanation is the most effective.

What This Answer Covers

This is a focused, single-point answer that gets directly to the core of the question without detours.

How This Compares in Science

Ranked #324 of 500 Science questions by answer depth (top 66%). This is in the concise tier — a focused explanation that prioritizes clarity over exhaustiveness. Many readers prefer this level of directness.

Frequently Asked Questions

Is there a simple explanation for why white things turn yellow if they stay in light?

It's not that they're white, it's that they're made of a type of plastic that, after prolong exposure to light, will degrade, becoming yellowed and brittle. UV is bad for that type of plastic, so the more time it spends in direct sunlight, the more…

How detailed is this explanation compared to similar Science questions?

This is a focused answer at 47 words, ranked #324 of 500 Science questions by depth. The key concepts covered are it's, they're, type.

What approach does this answer take to explain white things turn yellow if they stay in light?

The explanation uses direct explanation across 47 words. It is categorized under Science and addresses the question through 1 analytical lens.