Hydroponics
Hydroponics is a way to grow plants in water with added food instead of soil.
A clear glass holds water mixed with plant food. A small plant sits inside with its roots dangling down into the liquid. The roots soak up water and food directly. No soil is needed — the water does all the work.
Explaining hydroponics by grade level
Think about a radish seed. You can grow it in dirt, or you can grow it in water. The water has plant food mixed in. The roots drink it up and the plant grows tall without any soil at all.
Projects that explore hydroponics
Hydroponics replaces soil with nutrient-rich water so roots absorb food directly from liquid. This experiment compares three methods: a soil tray, a water culture system with an air pump, and a flood-and-drain system. The soil-grown radishes actually grew tallest, showing that water-based growing does not always outperform dirt.
Growing plants in water with added food does not guarantee bigger results for every species. Some plants still perform better when their roots spread through soil. This experiment tested radishes, cucumbers, snapdragons, grass, and bachelor's buttons in both setups, and all five types grew better in soil after 35 days.