(WHTM) — On a perfect day, you may look up and see many different types of clouds: fluffy and white, low and grey, or light and wispy looking. If you have flown on an airplane, sometimes you fly right through them.

They look light and airy. But, are they really?

You’d be surprised to know that the average cumulus cloud — often called a fair-weather cloud — can weigh around 1.1 million pounds, according to the United States Geological Survey (USGS). To visualize this, this is about the weight of 40 school buses or an Airbus A380 passenger jet.

But how can this be? How can something that looks so light weigh so much?

Well first, you have to know that clouds are made up of many tiny water droplets. Because they are made up of water, they have mass.

Next, according to Science Alert, scientists worked out that the water density inside a cumulus cloud is about 1/2 gram of water per cubic meter, which can be equated to a marble worth of water in a box that is large enough for two people to sit in. Which is very, very small.

Now that we have the density of the clouds, we have figured out how big it is, which can range from extremely small to extremely large. The good news is that a researcher with the U.S. National Center of Atmospheric Research calculated that the average cumulus is about a kilometer across and roughly has the shape of a cube, so it’s as tall as it is wide.

Now, if you calculate all of that, you have got a cloud with a volume of one billion cubic meters. Then, if you multiply that number by the density, you get the answer of 1.1 million pounds, or the weight of 100 elephants.

The reason why these extremely heavy objects don’t fall out of the sky is rather simple. The weight of a cloud is spread out so thinly that gravity has no effect on them. Because they are made of condensation, they become buoyant.

Now, after reading all of that, I’m pretty sure you will never look at a cloud the same way ever again. I guess the saying ‘looks can be deceiving” is true after all!