Subjects
Explore
Play
84 lessons · 1st Grade
Weather is what is happening in the sky right now: sunny, rainy, snowy, or windy.
The water cycle goes round and round: water evaporates, forms clouds, falls as rain, and collects in rivers and oceans.
Clouds come in different types: fluffy cumulus, flat stratus, and wispy cirrus clouds.
A flood happens when too much rain falls and water overflows rivers and streams.
Minerals are found in rocks. Some minerals are shiny, some are dull, some are colorful.
Soil is made of tiny rocks, dead plants, water, and air. Plants grow in soil.
The four seasons—spring, summer, fall, and winter—happen because Earth tilts as it goes around the sun.
Wind and water change the shape of land over time. This is called erosion.
Rivers flow from high places to low places, carrying water, sand, and tiny rocks along the way.
Earth has many different landforms: mountains, valleys, plains, hills, and plateaus.
Rain fills up rivers, lakes, and ponds. Animals and plants need this water to live.
Climate is the usual weather in a place over a long time. Deserts are hot and dry, rainforests are warm and wet.
Fossils are imprints or remains of living things from long ago, found in rocks.
Sand at the beach was once big rocks that broke down over millions of years.
A weather vane shows which direction the wind is blowing. A windsock does too!
Clouds form when water vapor rises, cools, and turns into tiny water droplets.
Rocks can be sorted by size, color, shape, and texture. Geologists study rocks to learn about Earth!
A volcano is a mountain that can erupt, sending hot melted rock called lava to the surface.
The sun warms the land and water, which warms the air. Warm air rises and cool air sinks.
Earthquakes happen when the ground shakes. They are caused by movement deep under the Earth's surface.
A tornado is a powerful spinning wind that comes down from a thunderstorm cloud.
Glaciers are huge sheets of ice that move very slowly and shape the land beneath them.
Rocks are always changing! Wind, water, and ice break them down very slowly.
The ocean covers most of Earth's surface. Ocean water is salty!
A compass always points north because Earth has a magnetic field.
A thermometer measures how hot or cold the air is. We use degrees to describe temperature.
Mud forms when soil gets very wet. Some animals like worms love mud!
Layers of rock tell the story of Earth's history. Older layers are at the bottom!
Stalactites hang from cave ceilings. They form from water dripping and leaving minerals behind.
A drought happens when an area gets very little rain for a long time.