Mica powder is an environmentally-friendly alternative to plastic glitter, and gives off a way more swirly, iridescent effect. Fill the jar with water, pour in the mica powder, and hot glue the lid on the jar. If someone's throwing a tantrum, shake up the jar and tell them to sit quietly until the glitter slows. Learn more here.
Get 24 colors of mica powder from Amazon for $11.99.