How to Grow a Sugar Crystal

Scouts can grow a sugar crystal with common household supplies. This is a STEM activity they can start at a meeting and then take home with them.

When a sugar solution is created, sugar is completely dissolved in the water. As the water evaporates, some of the sugar molecules are attracted to each other and join together to form a small group of molecules. As this process continues, eventually enough of the molecules become attached together in a regular pattern and a crystal is formed.

When making the crystals, make sure they keep adding sugar until it really won’t dissolve anymore and it will be successful.

Equipment

• Glass jar with a wide mouth
• Pencil (long enough to be placed across the top of the jar without falling in)
• Rough string or yarn (don’t use nylon)
• scissors
• Paperclip
• Pan to boil the water in (see notes)
• spoon

Materials  

• 3 cups sugar
• 1 cup water

Instructions 

• Cut the string a few inches longer than the height of the jar.
• Tie the paperclip to one end of the string.
• Tie the other end of the string to the pencil.
• Place the pencil on top of the jar so the paperclip is hanging inside the jar. The knot on the paperclip should be hanging about an inch above the bottom of the jar. If it is not, adjust the string until it is the correct length.
• Remove the pencil and string from the top of the jar.
• Place the water into the pan and bring to a boil.
• Remove the water from the heat. (Use safety precautions!)
• Add on spoonful of sugar to the hot water and stir to dissolve.
• Continue adding and stirring the sugar until it won’t dissolve in the hot water any more. If the sugar starts accumulating on the bottom, even after stirring, then the solution is saturated and the sugar will not dissolve. That is when you should stop adding sugar.
• Carefully pour the sugar water solution into the jar.
• Moisten the end of the string with the paperclip on it and drag it through some sugar so that the sugar sticks to it. (This gives the crystal a start.)
• Place the pencil with the string back on top of the jar so the paperclip and string are hanging in the solution.
• Place the uncovered jar somewhere where it will not be disturbed for at least two weeks.
• After two weeks, remove the string from the jar. You should see a nice sugar crystal on it.

Notes

If you are doing this during a meeting and you can’t boil water during the meeting itself because you don’t have access to a stove, then make the sugar/water solution beforehand.