Grow crystals

What can we use instead of a clear glass jar or a popsicle stick if we don't have them?

Use a clean clear plastic cup or a mason jar that can hold hot liquid instead of the glass jar, and substitute a pencil, chopstick, or wooden skewer for the popsicle stick while still tying the string so it hangs without touching the sides or bottom.

Why did crystals not form or why is my solution cloudy, and how can I fix it?

If crystals don't form or the solution is cloudy, reheat the water (step 3), keep adding and stirring one tablespoon of salt or sugar until extra granules stop dissolving so the solution is saturated (steps 4–5), ensure the string hangs freely without touching the jar sides or bottom (steps 8–9), and place the jar somewhere safe and undisturbed (step 11).

How can I adapt the activity for younger or older children?

For preschoolers have an adult handle the heating and pouring (steps 2–6) while the child adds food coloring, stirs, and makes simple measurements, and for older kids have them run multiple jars (salt vs sugar), vary food coloring or string materials, and record daily crystal lengths and photos for comparison (steps 6, 9, 10–12).

How can we extend or personalize the crystal-growing activity once the basic crystals form?

To extend the project twist a pipe cleaner or bend a paperclip into a shape and tie it to the pencil so crystals grow on the shape, try different food coloring drops in separate jars, and create a growth chart with daily measurements and photos to compare results (steps 6, 8–12).