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Have you ever wondered about the secret that hides inside every green leaf, every blade of grass, and every tall tree? I am that secret. I am a silent chef, working inside my green kitchens all day long. I don't use a stove or an oven. My ingredients are much more magical. For breakfast, lunch, and dinner, I take a long, warm drink of pure sunshine. Then, I take a deep gulp of the air around me and a cool sip of water from the ground below. With these simple ingredients, I stir and simmer and cook up the most delicious sugary meal you can imagine, a special energy-filled treat that helps my plant friends grow tall and strong. But I don't keep all the magic for myself. While I'm cooking, I release a special gift into the air. It’s an invisible present, something that every animal and every person needs for every single breath they take. You can't see me, but you can feel my work all around you. I am the reason the world is full of life and fresh air. I am Photosynthesis.

For thousands of years, my secret recipe was a complete mystery. People saw plants grow, but they had no idea how. In the 1600s, a curious man named Jan van Helmont decided to investigate. He planted a small willow tree in a big pot of soil and weighed them both carefully. For five whole years, he gave the tree nothing but water. He watched as it grew from a little sapling into a huge, leafy tree. When he weighed it again, the tree was much, much heavier, but the soil in the pot had barely lost any weight at all! He was amazed and thought my magic must come only from water. He was on the right track, but he was missing a few key ingredients. Over a hundred years later, in the 1770s, a scientist named Joseph Priestley got even closer to the truth. He loved doing experiments with glass jars. He discovered that if he lit a candle and put a jar over it, the flame would quickly go out. When he put a mouse under the jar, the poor thing couldn't breathe. The air, he realized, was being used up. But then he tried something new. He put a sprig of a mint plant under the jar with the mouse, and something wonderful happened. The mouse was perfectly fine, and a candle could even be relit inside the jar. He declared that plants must 'refresh' the air. He was right. Finally, on August 2nd, 1779, a man named Jan Ingenhousz added the last, most important clue. He figured out that I only do my work of refreshing the air when the sun is shining on me. At last, my secret recipe was revealed: I use sunlight, water, and a gas from the air called carbon dioxide to make sugary food for the plant, and as a gift, I release fresh oxygen for you to breathe.

My work is connected to your life in more ways than you can imagine. Can you picture the juicy apple you had for a snack, or the fluffy bread in your sandwich? That's me. The energy in that food started as a ray of sunshine that I captured and turned into something delicious and strong. The wood used to build your house and the paper in the books you read all began with a tiny seed and my sun-powered work. Even the cotton in your t-shirt grew on a plant that I helped feed. But my most important job of all is making the oxygen that fills your lungs with every single breath you take, whether you are running on the playground or sleeping in your bed. I am your silent, sunny partner. I work quietly in the giant, rustling forests, the grassy parks, and even in the little potted plant on your windowsill. Every time you help take care of a plant, you are also taking care of me. And together, you and I and all the green things on Earth work as a team to make our world a beautiful, healthy, and wonderfully breathable place to live.