Nature & Environment

Cloud names are built from two halves: how high it sits, and what shape it is. Learn the six kinds and you can read the weather off the sky.

You need no equipment to start watching the weather. Just a window, somewhere to write things down, and the habit of looking up.

Each raindrop bends sunlight, splits it into every color hidden inside it, and reflects it back to you. That is the whole trick behind the arc.

Every drop of water on Earth gets recycled through the same four steps. You have made a cloud yourself, on every cold day of your life.

Puffy clouds have lumpy tops and flat bottoms, all sitting at the same height. That flat line marks the exact height where rising air turns into cloud.

A rainbow is not in a place. It is an angle, so it backs away as you walk toward it, and the person beside you is looking at a different one.

Everything we know about dinosaurs comes from bones that turned to stone. The bone did not harden. It left, one speck at a time, and rock took its place.

Travel back far enough and you reach a world run by dinosaurs. Here is what we know about them, how we know it, and what nobody has found yet.

A crystal's flat faces and sharp edges are carved by nobody. They come from the way it is built, right down at the level of its atoms.

A volcano is a mountain with an opening leading all the way down to melted rock, and one of the few places you can watch Earth's inside arrive.

The angle between two faces of a quartz crystal is always 120 degrees. Every crystal, any size, ever measured. Nothing else about the shape is fixed.

How runny the magma is decides the shape before the eruption even starts. Runny magma lets its gas escape; thick magma traps it and blows the top off.

A fungus has no mouth and no stomach, so it does the digesting first and outside. It turns its food into soup where the food lies, then drinks it.

Most of a tree's wood came out of the air, not the soil. A tree is a gas that has been caught, one molecule at a time, and stacked up.

A seed cannot walk, so every seed that lands somewhere new got a lift from something. Find out what, then check your socks after a walk.

The plant most likely to crowd out a new seedling is its own parent. That is what all those parachutes, hooks and husks are really for.

A mushroom is only the fruiting body. The fungus itself is hidden underground, and the biggest one on Earth covers over 2,000 acres.

Plants do something no animal can do. They build their own food out of thin air, water and sunshine. The name for it is photosynthesis.

Animals live in deserts, in the deep sea, and on ice. Look at where one lives and you can usually work out why it looks the way it does.

The ocean is not one place. Swim from a shallow reef out into open water and down into the dark and you pass through three completely different worlds.

A frog rebuilds its own body: it grows legs, swaps gills for lungs, and eats its own tail. Follow the change one stage at a time.

Honey does not start as honey. It starts as a thin, watery liquid inside a flower, and it takes a whole hive to turn it into the thick stuff.

Winter is hard for animals, and the reason is not only the cold. It is the food. Three animals wait it out, and no two do it the same way.

Bees build the shape that holds the most honey for the least wax. Only three shapes tile with no gaps at all, and hexagons win on wall.

Nectar is sugar a plant worked hard to make, handed out to anything that calls. It is not a gift. It is a fare, and some insects dodge paying it.

Squeeze soil from under a hedge and it falls into little balls. Squeeze it from a bare path and it turns to powder. Living things make the difference.

Sea otters never eat seaweed. Take them away and the seaweed forest vanishes anyway, because the otter's effect travels through something else.

Count the animals in any garden and the small ones always win. The reason is arithmetic: only about a tenth of a meal ever reaches the animal above.