WARNING: Make sure to do the following project with a parent for extra precaution.
NOTE: Make sure to do this outside due to the mess it will make.

To Make Pom Pom Crystals, you will need:
Epsom salt
Clear glass jar or bottle – If you’re using a bottle, you also need a funnel.
Small pom-poms
Access to hot tap water
Spoon
Measuring cup

Instructions:
Put one cup of the epsom salt in the clear glass jar or bottle.
Carefully pour one cup of very hot tap water into the jar or bottle.
Stir the mixture together. There might be undissolved epsom salt at the bottom of the jar, that is fine.
Add the small pom-poms and stir it some more.
Place the jar in the refrigerator. Make sure it is in a location where it won’t be disturbed.
Check on it the next morning.
Feel free to pour off an extra liquid and touch the crystals, just remember that they are crystals and could break easily.

Cites:

Grow A Crystal Garden Kitchen Science Experiment

https://www.google.com/search?q=pom+pom+crystals&rlz=1CASFJY_enUS976&hl=en&source=lnms&tbm=isch&sa=X&ved=2ahUKEwiI3MD5ts30AhX5HzQIHdPDCdcQ_AUoAXoECAIQAw&biw=1366&bih=665&dpr=1&safe=active&ssui=on#imgrc=ovIboilM1JVFiM