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Home | Basket and experiments |
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Visit to Météo France |
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After some difficulties during our second release, especially the surprise ascension of our balloon into a cloud (whereas the temperature gradient was insufficient for its ascension), we met the technicians of Météo France Tours, one of our partners, to understand this phenomenon better.
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 Visite à Météo France, le 21/04/08 |
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What is a cloud ? This is what we learnt: a cloud is composed of millions of water droplets in suspension in the air (or ice crystals if the air temperature is low enough). We wondered about the occurrence of this phenomenon. A cloud forms when the water vapour contained in the air condenses into tiny particles. The density f the air decreases with the temperature. That’s why hot air rises and cold air goes down, because hot air is less dense than cold air. It’s what scientists call convection.
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Convection is one of the processes which result in the formation of clouds. When the sun heats the ground, the air which contains water vapour heats up and begins to rise. With this increase in altitude, the air cools down and causes the condensation (or the liquification) of water vapour which results in the creation of a cloud. This condensation which leads to the formation of a cloud can occur in many other causes. For example, the contact of a mass of hot air with the frozen summit of a mountain or the meeting of two masses of air, one hot and the other cold.
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What different types of clouds can be formed ?
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