Imagine you visit a desert like the Sahara. In the daytime it is burning hot — over 40°C! But the same night can drop close to 0°C, cold enough to make you shiver.
That is strange, right? The sand did not move. The desert did not move. So why does one place go from a frying pan to a freezer in a single day?
Let's solve this mystery together, one clue at a time. 🔍
During the day, sunlight beams straight down onto the open desert. There are almost no trees, clouds, or buildings to block it. The sand soaks up the heat and gets scorching hot.
Clue 1: the desert is great at collecting the sun's heat. ☀️
At night, the sun is gone. No more heat is coming in. Tap the buttons to switch between day and night and watch the desert.
At night nothing tops up the heat — so the warmth starts to leak away.
Here is the key clue. In wet, leafy places (like Singapore!) the air is full of water vapour and clouds. At night this acts like a cosy blanket — it traps heat near the ground so it can't escape.
The desert air is very dry with almost no clouds. So the blanket is missing. The heat shoots straight up into space and the ground cools down fast.
Tap a sky to send the heat up — and see which one keeps it in.
You now know the secret: a damp, cloudy sky traps heat; a dry, clear sky lets it escape. So which of these gets coldest after sunset?
Think about which sky has the thinnest blanket. 🤔
Water holds onto heat for a long time — that's why the sea stays cool by day and warm by night. But dry sand is different. It heats up fast in the sun and loses its heat just as fast when the sun sets.
Tap the sand and water to feel how each one changes after dark.
So deserts have a double problem: a dry sky and sand that drops its heat fast. ❄️
Deserts get cold at night because of three teamed-up reasons:
Next time someone says "deserts are always hot", you can tell them the cool truth! Detective badge earned 🏅