Using values known for volume, air density, and gravitational field, it gives a luminous energy of 11.8 Newtons, or 2.7 pounds.
Now, let’s replace that block of air with another block that is identical in shape and size. But this time, suppose it is 1 cubic meter of water with cub densityWater = 1,000 kg / m3.
Since it has the same volume as the floating air, this block will have exactly the same energetic force. What you put in that space is not considered if its size is 1 meter3, It is going to be a bright energy of 11.8 Newtons. But for this cube of water, letting it float is not enough. The gravitational force will pull it much bigger – it’s 9,800 Newtons. The water cube is just falling.
To increase luminosity rather than gravitational force, you need to fill that space with a substance that is less than air. There are two common ways to work in real life. One is to use a thin rubber container filled with a low density gas. (Think of a helium balloon.) The other is to use a low-mass container to hold hot air, which is less dense than cold air and will rise above it. (Think of a hot air balloon.)
So if you want a cloud to float, its density must be less than that of air. But how can that density be lower if there are both winds in the clouds And Water?
Because clouds don’t actually float.
Why is water size important?
Suppose a cloud consists of wind and very small water droplets. The size of the drop is important. You may be surprised to learn that although they are both made of water and have the same shape, small droplets do not behave like large droplets. To understand the difference between them, we need to look at wind resistance.
Let’s start with a quick demonstration. Keep your hand open in front of you. Now swing your arms back and forth so that your hands move quickly through the air. Do you feel anything? It may be slight, but there should be an interaction between your hand and the wind, a force to push back which we call wind resistance or wind tension. (If you stick your hand through a moving car window, you must notice it.)
We can model wind resistance on a moving object with the following equations: