Large copper sulfate crystals can be grown using a seed crystal.
Copper sulfate crystals are easy to make, and are a great introduction to chemistry for schoolchildren. No specialized equipment is needed, and copper sulfate can be purchased online or in home and garden stores. The experiment is safe as long as children are monitored, and can be performed at home or in a chemistry lab. The result is brilliant blue copper sulfate crystals of varying shapes and sizes, with large crystals possible given enough time.
Instructions
1. Make a super-saturated solution of copper sulfate. Heat distilled water in a beaker over low heat until it reaches around 122 degrees Fahrenheit. Add a small amount of copper sulfate and stir until it has fully dissolved. Keep adding and stirring until the copper sulfate stops dissolving and starts to settle on the bottom of the beaker. Heating the water allows more copper sulfate to be dissolved.
2. Grow a "seed crystal" by pouring some of the copper sulfate solution into an evaporating dish and leaving it for a day, somewhere where it won't be disturbed. As the water evaporates from the solution, small copper sulfate crystals will form. Pour the remaining solution from the beaker into a sealed container, clearly labeled to prevent the solution from being ingested accidentally.
3. Select one of the largest copper sulfate crystals in the evaporating dish, and tie it carefully to a piece of nylon fishing line. Fill a glass jar with the super-saturated copper sulfate solution you made previously.
4. Wrap the free end of the nylon fishing line around the middle of a pencil, and tie it off to keep the line in place. Place the pencil over the top of the glass jar, so the crystal is suspended in the copper sulfate solution. Make sure that the crystal is not touching the sides or the bottom of the jar.
5. Leave the jar undisturbed and uncovered, so the water from the solution can evaporate. Check the crystal daily; you should see it growing. If any crystals start forming on the sides or the bottom of the jar, pour the solution into a clean jar and move the crystal so it is suspended in the solution again. When the crystal has grown to a suitable size, you can remove it from the solution and display it.
Tags: copper sulfate, sulfate crystals, copper sulfate solution, from solution, sulfate solution, copper sulfate
