Grade 5 Reading — Science

Watersheds: Where Water Begins Its Journey

Every drop of rain that lands on your street eventually travels somewhere. The land area that drains into a common stream, river, or lake is called a watershed. Think of it like a giant bowl: ridges and hills form the rim, and all water inside flows toward the lowest point. Watersheds can be small, covering a single neighborhood creek, or enormous, like the Mississippi River basin that spans much of the central United States. Water moves through a watershed in stages. Precipitation falls as rain or snow. Some soaks into soil, where plant roots and underground layers called aquifers store it. Surface runoff flows across roads, fields, and forests, carrying sediment and nutrients. Streams merge into rivers that eventually reach the ocean unless people divert water for farms and cities. Healthy watersheds depend on vegetation. Trees and grasses slow runoff, filter pollutants, and hold soi…

Inside the Digestive System

Your body needs energy to think, run, and grow. Food supplies that energy, but a sandwich or apple must be broken into tiny molecules before cells can use it. The digestive system is the team of organs that processes meals from the moment you chew until waste leaves your body. Digestion begins in the mouth. Teeth grind food while saliva moistens it and starts breaking down starches. The tongue pushes the bolus, a soft ball of chewed food, toward the throat. Swallowing moves it into the esophagus, a muscular tube that squeezes food downward into the stomach. The stomach churns food with strong acid and enzymes that dissolve proteins. The resulting mixture, called chyme, enters the small intestine—a long, coiled tube where most nutrients are absorbed. The lining contains millions of villi, tiny fingerlike folds that increase surface area so blood can carry sugars, amino acids, and vitami…