He noticed this while doing the experiment. You can see this yourself, when you go out in the cold weather and breathe, it feels like you are breathing out smoke or fog. Actually, what you see as smoke or fog are the same tiny water droplets. The water vapour that you breathe out gets condensed into these tiny droplets. Exactly the same process that forms clouds.
So it’s not wrong to say that you can blow out a mini cloud during winter. Dr Shaefer also noticed the same thing but he took it one step further. He wondered about what would happen if he cooled the box down further. To do this, he used dry ice. Dry ice is basically a solid form of carbon dioxide. It is commonly used for refrigeration and cooling. And it exists only at a temperature of -78°C.
So he placed some dry ice in the cold box. And then when he breathed out into that box, he saw something miraculous. The air that he blew out suddenly turned into millions of microscopic ice crystals. He saw it as a blueish haze. He noticed that if the temperature is reduced suddenly, then the water vapour will instantly turn into ice crystals. This thing happens in clouds at the last stage. When those ice crystals become huge and heavier than the atmosphere. He saw that using dry ice has sped up this process.
