Your baby will develop their ability to visually track objects as they watch bubbles slowly floating past them.
As they develop control of their movements, they will be able to move their hands towards the bubble. When they touch one, they will discover that the bubble pops, helping them to link their action with what happens. This is another experience of cause and effect. When they are older, your baby might expand on this as they realise that sometimes they can stop a bubble and hold it without it popping!
Bubbles are also great for language development; if you hold a bubble stick or wand close to your face and pause a moment, this encourages your baby to look at you as they wait for one to be blown! You could make it a game by saying, “Ready, steady, go!” before you launch the next floating marvel!