Episode Details

In the next few minutes we're going to track that sugar down. First we prove it never actually left. Then we find out that water can only hide so much, and what happens when it runs out of room.

The crystals that appear on cooling are the hidden stuff coming back, and that answers both opening questions. It never left, because mass is conserved, and you get it back by shrinking the water's hiding room, which means cooling it. Even a saturated solution that looks still is busy, with particles dissolving and re-forming crystals at exactly the same rate. The listener can now state the quantity: solubility is grams of solute per 100 g of water at a given temperature.

Sources:

• https://www.creative-chemistry.org.uk/documents/N-m21-04.pdf
• https://www.cliffsnotes.com/study-notes/33679916
• https://www.chemguide.co.uk/physical/phaseeqia/saltsoln.html

Source: Episode 8 - Chemistry Level 8, Chapter 3: Separation techniques (2/4). Dissolving (3.3-3.4), about 5-6 min
Sections: 3.3, 3.4
Style: Exam prep
Length: 1063 words, 6 min target
Generated: 2026-10-25