How do small salt crystals grow?
Invisible dissolved salt can become visible grains again. Follow its journey step by step.
The short answer
When water evaporates from a salt solution, the salt remains. Its tiny building blocks can join in a regular arrangement. This forms growing crystals, given suitable conditions and time.
Equal-sized adult Wusels examine two shallow dishes behind glass: one with liquid and one with enlarged cube-like salt crystals. Invented museum comparison; crystals are enlarged for visibility. A closed showcase is not an evaporation activity setup. AI-created illustration, not a photograph of nature.
What the diagram shows
The diagram simplifies the process. First compare its shapes and arrows. You can read its labels in larger text below.
Read the picture labels
These are the words and sentences from the diagram above. The full explanation follows below.
- From dissolved salt to new crystals
- 1. Dissolved
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- 12 salt building blocks
- 2. Less water
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- 12 salt building blocks
- 3. Salt remains
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- 12 salt building blocks
- Water particles; only these leave the dish here
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- Sodium ion
- Chloride ion
- Simplified flat model; real crystals are three-dimensional and contain far more than 12 ions. Colors, spacing, water counts and timing are not to scale or measurement results.
An imagined Wusel scene
Puschel and Flauschi investigate
Puschel sees less water in the labelled dish and assumes less salt. Flauschi shows him small solid shapes at the edge. They compare the starting drawing with the later state. Water evaporated while salt became visibly ordered.
Look closely
The Wusels examine two invented exhibits: liquid on the left and enlarged salt crystals on the right. The showcase is a comparison, not evaporation happening live. Grains in your own activity are usually much smaller. The separate diagram explains the route from dissolved salt to crystals.
An example to help you understand
Draw your dish on the first day and again later. Record whether less liquid is visible and whether new solid grains have appeared. Add the date. If you tipped undissolved salt into the dish before waiting, old grains are difficult to distinguish from newly formed ones. That is why we start with clear salt solution. Compare your actual observation with the diagram: a few colored dots stand for unimaginably many building blocks. Count the salt dots in all three panels. Their number stays the same; fewer water dots remain. The drawing is greatly simplified, not a real microscope image.
Try explaining it
What remains when water evaporates from a salt solution?
Choose a), b) or c), then explain your choice.
- a)Water from which the salt disappeared through evaporation.
- b)Salt newly made from water by evaporation.
- c)Salt whose building blocks can form crystals.
Show the explanation
Correct: c): Salt whose building blocks can form crystals.
When water evaporates from a salt solution, the salt remains. Its tiny building blocks can join in a regular arrangement. This forms growing crystals, given suitable conditions and time.
Word help
- evaporation
- Liquid becomes gas at its surface, even without boiling.
- crystal
- A solid with tiny building blocks arranged in a regular pattern.
Explore in more detail
Here you will find longer explanations and further details. You can explore them together.
1. Dissolved does not mean gone
Tiny building blocks sit closely together in a salt grain. Water can separate and surround them. The dispersed building blocks are too small for us to see individually. This mixture is called a solution: the substance is distributed in water. Here, the building blocks are sodium ions and chloride ions. An ion is a tiny chemical building block with an electric charge. The names identify two different kinds of building blocks in table salt. Sodium ions are positively charged and chloride ions negatively charged; plus and minus show this in the diagram. Opposite charges attract.
Checked against: [2]
2. Water leaves the dish
Some water particles leave the surface and spread into the air. This is evaporation. Water becomes a gas: invisible water vapor distributed in the air. It does not have to boil. Our open dish gradually contains less water. The process takes different amounts of time depending on conditions. A closed museum showcase is therefore not a suitable place for our open observation activity.
Checked against: [4]
3. Building blocks arrange themselves again
As water evaporates, dissolved salt remains. With less water, solid salt crystals can eventually form: salt building blocks join in a regular arrangement again. A crystal is a solid whose building blocks repeat in an ordered pattern. No living thing grows, and no new salt appears from nothing. Its building blocks were already in the solution. The same basic idea is used to obtain salt from seawater.
Checked against: [3]
4. Observe rather than perform magic
Ask an adult to stir a small amount of salt water: about one teaspoon of salt with four teaspoons of room-temperature water. Stir gently until as much as possible dissolves. Put some clear liquid in a shallow plastic dish; leave undissolved grains in the cup. Observe daily without touching. Small crystals may become visible over time, often with angular, cube-like shapes. Many small grains are a result too. If water remains, keep observing; no particular deadline or large single crystal is promised.
Checked against: [1]
An optional question for further exploration
You can use the longer explanation above. This is extra, not needed for the first quiz.
An extra question
There is less water in our dish. Must the salt also leave as a gas?
Discover the answer
No. In this observation, water evaporates while salt remains and can form crystals. Less visible liquid does not mean every substance disappears from the dish.
Pictures and sources for adults
Sources for further reading
Facts checked against the specialist sources below on 12 October 2026. The Wusel scene is fictional; comparisons and simplified models are explicitly explained. Sources are in English.