Add 1 tablespoon of Orbeez to a large bowl and pour in about 2 cups of water.This will give you more water beads than you need, but without this amount you won't have enough of each colour.Keep an eye on the bowl to make sure it doesn't overflow, and that the Orbeez are always covered in water as they grow.
Rinse out an empty water bottle to make sure it's clean. Once the bottle is dry, remove the label.
Clean the outside of the bottle to remove any glue. You can wipe it with rubbing alcohol, Goo Gone, or simply soak the bottle in warm, soapy water.
Step 3: Sort the Orbeez and add them to the bottle
Check on the Orbeez after about 3 hours. They should have grown to about 100 times their size, or 1 cm across.Add more water or let them sit longer if you want the water beads to be bigger.
Sort the Orbeez by colour into separate bowls or jars. There will be extra colours (and clear ones), but we used red, orange, yellow, green, blue, and purple for this sensory bottle.
Divide the height of your bottle by 6 or 7 (the number of colours you have). Add the first colour of Orbeez (red, for us) until it reaches that height.You can also guesstimate the amount if you don't want to measure.
Add an equal amount of the next colour in the rainbow.
Repeat with the rest of the colours, filling the bottle to the very top. This will stop the water beads from mixing.
Place the lid on the bottle, closing it tightly.
Your rainbow sensory bottle is complete!
You can also add water or baby oil to create different water bead sensory bottles. Read below for more details!