Weather is the one branch of science where a child can collect real data every single day without leaving the garden. These weather experiments for kids cover cloud formation, pressure, wind, and rain — and most end with an instrument they built themselves. Build Your Own Station Four instruments cover everything a home station needs. … Read more
How do clouds form? Warm air holds water vapor; cool it enough and it cannot hold it all, so the excess condenses into visible droplets. But there is a catch that makes the whole thing work: vapor will not condense into nothing. It needs a surface — a speck of dust, salt, smoke, or pollen … Read more
What is the water cycle? It is the continuous movement of water between the ocean, the atmosphere, the land, and back — driven by solar energy and gravity, with no beginning and no end. The total amount of water on Earth has been essentially fixed for billions of years. What changes is where it is … Read more
What causes global warming? An energy imbalance. Greenhouse gases in the atmosphere are transparent to incoming sunlight but absorb outgoing infrared radiation, so heat that should escape to space is retained. Add more of those gases and the planet warms until it radiates enough to rebalance. That is the entire mechanism, and it has been … Read more
How do ocean currents work? There are really two separate systems that happen to connect. Surface currents are pushed by wind. Deep currents are driven by density differences — cold, salty water sinking and spreading. Together they move an astonishing amount of heat around the planet, and they are a large part of why coastal … Read more
Why is the ocean salty? Because water flows toward the ocean carrying dissolved minerals, and the only way out is evaporation — which leaves the minerals behind. Over hundreds of millions of years, that one-way process has concentrated a great deal of salt. Rivers, by contrast, are constantly refreshed by rain and snow, so they … Read more