Bubble
If you don't already know how much fun children get from playing with plastic straws, now you have the opportunity. Bring a few plastic cups or bowls and a few straws into the bathroom. Have your child pour different amounts of water into them and try to blow bubbles in each one. In what volume of water is it easier to blow bubbles - small or large? Invite him to blow a huge bubble right in the bath, or as many bubbles as possible, or a hundred small bubbles, or just two bubbles. He will have fun doing a science experiment.
Caution: Blowing bubbles is not safe for the breathing of very young children. Wait until they're older and you'll have no problem keeping soap away from their eyes, ears, and mouths.
Usually children's fun can be organized from what is at hand. But if you know in advance that you will be entertaining a group of children, go to a store that sells all sorts of things and buy a special jar for blowing soap bubbles. One such jar contains real magic - children's laughter and happiness.
How to save soap: An excited child with a full jar of soap suds in his hands may accidentally spill it. Open all the jars and pour half of the liquid from each into a jug (or some other vessel). If the jar tips over, then all is not lost, and, besides, when the children finish their soapy fun, you can fill the jars for future use, for next time.
Bubbles are especially great if you need to keep children of different ages occupied. Even teenagers enjoy them. Depending on what you blow into, bubbles of various sizes are formed. Very small bubbles fly out of plastic straws dipped into a soap solution. The lids of plastic jars with a hole in the middle blow out bigger bubbles. If the tool you choose is too large for a jar of foam, pour the soap solution into a bowl and put your tool in it, then take it out with tongs, shake it, and you will see how huge and rainbow-colored bubbles you get.