Supplies: water bottles, water, food coloring or liquid watercolor, glitter and sequins, vegetable oil.
- Water: Children fill bottles 2/3 to 3/4 of the way with water.
- Color: Ask the child to predict – will the color mix throughout the water or stay separated? Add the color to test their prediction and notice how it mixes completely.
- Glitter and sequins: Ask the child to predict – will the glitter dissolve and mix into the water? Add the glitter. Observe what happens. Put the lid on, shake it, observe what happens. The glitter is suspended and then settles out.
- Oil: Ask the child to predict – will the oil mix in? Add oil – we use an inch or two – try to leave maybe a inch or so of space at the top of the liquid so they can see the splashing when they shake. Observe how the oil floats on top of the water. Put the lid on and shake it – it intersperses, then separates. Oil and water are immiscible fluids.
- Experiment more: Lay the bottle on its side and tip it gently back and forth – the liquid creates slow motion waves with the oil floating on top.
- Put the lid on. We recommend gluing it on with super glue or taping it on with duct tape to keep it sealed when the child plays with it.
You can have the children decorate the bottle before or after filling it: we use Tacky glue to attach “gems.”
You could start with warm water, and as your first step add some water soluble glue (like Elmer’s) and see whether it dissolves into the water. The glue has the added benefit of making the water more viscous so this means the glitter stays suspended for longer, which can be nice for a meditation bottle. Other ways to slow down how quickly the glitter settles out are to add some corn syrup, glycerin, dish soap, or hand soap. Experiment to see which mixture helps suspend the glitter for a pleasing amount of time.
Glitter is bad for the environment. We no longer buy it, but we have old supplies we are using up. If you prefer, you could use: small shells, sand, plastic buttons, or beads. If you use these heavier items, you can use glue or soap to slow down their fall. Learn more.
You can make two color bottles by adding an oil-based food coloring to your oil.
The nicer the water bottle, the nicer the final product will be. Usually we ask parents to each bring a water bottle in, but this year, we used the project as an opportunity to use up and replace the water bottles that had been in our emergency supplies for over two years.
This project goes nicely with my book about chemistry, which addresses mixtures, solutions, suspensions and immiscible liquids. The free book is called Mixing It Up. You can print one from this PDF. (Note: it’s set up to print on an 11×17 double-sided printer, but will scale down to print on 8.5 x 11 paper, and if you have to print single sided, you should be able to assemble it OK.)