Only use Gatorade or G2 bottles for the sensory bottles they are a heavier plastic so they hold up better and keep a unison look so everything looks good. They come in different sizes you can find smaller ones for small hands if you need to.
Make sure to ALWAYS seal your bottles securely! I cannot emphasize this enough. Unless you want your bottle opened and the contents poured out. SEAL IT… with glue. Duct tape can be peeled off by a determined kiddo. Glue is much harder for them to open up.
Glow in the Dark Bottle
Add small glow in the dark items such as stars to a bottle. Do not add any water. Children can put the bottle under a box, and look through a hole to observe what happens when the bottle is placed in the dark. Or they can take the bottle to a darkened room, or under a table covered with a sheet.
For a list of ALL my amazing DISCOVERY BOTTLE IDEAS click the link or the image below