From the Author Note about wind:

WIND IS A WONDER! It has no shape, smell, or taste of its own-it is invisible! Wind can be powerful enough to knock down trees or gentle enough to sneak up and tickle the back of your neck.

WIND IS MOVING AIR. Hot air is lighter so it rises up high, and cold air is heavier so it sinks down low. When there is a difference in temperature, wind tries to keep things in balance, so it blows from high to low. The greater the temperature difference, the stronger the wind.

WIND HELPS PLANTS GROW. Many plants depend on wind to spread their seeds. It's the most important pollinator, even more than bees.

WIND MAKES WEATHER. Wind spreads the sun's heat around the world giving our planet a more moderate climate. Without wind, most places would be too hot or too cold to grow food. Wind also blows moisture that rises into the air above oceans onto the land to make rain, ice, or snow.

WIND CAUSES EROSION. Wind can change the landscape as it sweeps sand, dust, and dirt across the land. When wind deposits dust over a large area, it can create a rich farming soil called loess.

WIND MAKES WAVES. By blowing across the surface of the ocean, the wind makes waves. Beaches are then pounded by waves, slowly crushing rock into tiny grains of sand.

WINDS HAVE NAMES. People around the world give wind different names. The Chinook wind, or "snow eater," blows across the Rocky Mountains, bringing warm, dry air that melts snow and raises winter temperatures dramatically.

WIND HELPS BIRDS. Birds can rest their wings and soar high in the sky by riding pockets of warm air that rise. When moving air runs into a cliff, mountain, or building, that air flows up and over the obstacle. Birds can "ride" these currents, like waves in the sky.