Grow and Compare Crystals
A real industrial process — crystallization — done safely on a kitchen counter.
Related field: Chemical Engineering
Mission Briefing
Objective
Grow crystals from a saturated solution and figure out what changes how big or how fast they grow.
Constraints
- Only sugar or salt, water, and a container are allowed — no other chemicals
- Adult supervision required for any heating of water
- You must test at least two different conditions (like concentration or cooling speed) to have something to compare
Concept You're Testing
Crystallization and saturation — the process of dissolving a solid into a liquid until it can't hold any more, then controlling how it comes back out as solid crystals. This exact process is used industrially in sugar refining and drug manufacturing, just at a much larger scale.
What You'll Need
- Sugar or table salt
- Warm water (adult supervision if heating on a stove)
- A clear cup or jar
- A piece of string and a pencil to suspend it (optional, for larger crystals)
Ask an adult to help with heating the water — this uses a stove or a similarly hot source.
Instructions
- 1With adult help, dissolve sugar or salt into warm water, stirring until no more will dissolve — this is your saturated solution.
- 2Pour it into a clear container. If using a string, suspend it so it hangs into the solution without touching the sides.
- 3Set it somewhere undisturbed and let it sit for several days.
- 4Make a second batch with one condition changed — for example, a more concentrated solution, or one that cools faster (like putting it in a fridge instead of leaving it at room temperature).
- 5Check both containers daily and note when crystals start to appear.
- 6After several days, compare the crystals from both batches.
How to Measure Results
Compare the size, quantity, and speed of crystal formation between your two conditions — which one produced bigger crystals, and which one produced them faster?
Skills You'll Practice
- What saturation actually means at a hands-on level, not just as a textbook term
- Why changing one condition (concentration, temperature, cooling speed) changes the result
- Patience with a process that takes days, not minutes — much industrial engineering work does
- Careful observation and comparison across two controlled conditions
If It Doesn't Work the First Time
That's normal — this challenge follows the same design process real engineers use. A failed test just tells you where to go back and improve.
Figure out what problem you're actually solving, and what would even count as success. Skip this step and jump straight to building, and a lot of bad designs happen right here.