Have you ever noticed that soap bubbles go up in winter and fall down in summer? The reason is that warm air is lighter than cold. And in winter the difference between the air temperature in the room (especially near the windows) and the one you exhale into the bubble is enough to overcome the heaviness of its shell.
Filling soap bubbles with hydrogen, you can see them flying up and on the hottest summer day. The summer air is warm and light, but it is still heavier than hydrogen.
To get bubbles with size of a large apple, one should take a completely clean so-called Marseille soap, make small chips and dissolve in water, then add glycerin to it.
Soap and glycerin should be taken equally (for example, 5 grams each). Distilled or soft rainwater should be taken four times (in this case - 20 grams) more than soap. After pouring soap into the vial and the bay with water, leave it for a day, then add glycerin and, after mixing well, allow the mixture to stand still for 24 hours. Such a mixture will serve you for a long time; for experiments it is enough to take each time a teaspoonful.
Having fixed in the hole of the gas pipe of the device for obtaining hydrogen a straw with split ends, it is easy to learn to blow out large bubbles. It is only necessary to change the gas pipe several times, putting a piece of rubber on its end, and at the other end of it inserting a glass tube with a drawn end. Clamping the rubber tube with your fingers, you can adjust the speed of blowing.
After pouring soapy water into a deep plate, and immersing the end of the gas outlet tube into it, one will get a whole mountain of soap foam. If the plate is taken away from the device with hydrogen, the foam can be blown up.