A curious child holds a sugar spoon above one clear glass.

Can water get too full?

tap the sugar spoon

One spoon vanishes into a drink. Then another. If you keep stirring, can every spoon disappear?

first, find the missing sugar

Gone from sight is not gone

Gold dots stand for sugar in our model. A piece can leave the solid and spread through the water, still sugar all the way.

gold dot = modeled sugar
now watch both directions

Sugar traffic goes both ways

same 16 pieces12 solid · 4 dissolved
larger solidsmaller solid

When more pieces leave than return, the visible solid shrinks.

add equal spoonfuls

Find the full point

0 dissolved · 0 solid

At the limit, pieces still move both ways. Their average rates match.

same temperature · same 20 pieces

Stirring changes the trip, not the finish

time passingboth just started
just startedlong enough

Fast stirring arrives sooner. At one temperature, both limits match.

now change temperature

A fresh warm jar starts clear

A child and grown-up inspect one starter crystal on a string in a clear jar. tap the starter crystal
temperature changes the limitwarm limit · 24 pieces
cool · 14warm · 24

This dial compares limits. It does not cool the jar.

One clear jar. One starter crystal. Only temperature changes.

As a warm, sugar-packed jar cools around a string with one starter crystal, what will the extra dissolved sugar do?