Science

Habitat

A habitat is the place where an animal or plant lives and finds what it needs.

Rainforests Are Diverse

Rainforests are full of many different species of plants and animals.

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Deserts Get Little Rain

Deserts are dry places that receive very little rainfall each year.

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Recycling

Recycling helps save resources and reduces trash in landfills.

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Renewable Energy

Wind and sunlight are renewable energy sources that won’t run out.

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Earth’s Layers

Earth has a crust, mantle, and core.

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Fossils

Fossils are remains or traces of ancient living things preserved in rock.

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Volcano Rocks

When lava cools, it becomes igneous rock and can build new land.

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Oceans Are Salty

Ocean water is salty because it contains dissolved minerals.

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Antarctica Is Coldest

Antarctica is the coldest continent on Earth.

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Atmosphere Mix

Earth’s air is mostly nitrogen and oxygen.

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Roots and Stems

Roots take in water and hold plants in place; stems carry water and support leaves.

Seeds to Plants

Most plants begin life as seeds that sprout into seedlings.

Amphibians

Amphibians like frogs live part of their lives in water and part on land.

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Reptiles Are Cold-Blooded

Reptiles are ectotherms, so their body temperature depends on their environment.

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Migration

Many birds migrate, flying to warmer places during winter.

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Hibernation

Some animals sleep deeply through winter to save energy; this is hibernation.

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Camouflage

Camouflage helps animals blend into their habitats to hide or hunt.

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Bees Pollinate

Bees move pollen between flowers, helping plants make seeds and fruit.

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Dolphins Are Mammals

Dolphins breathe air and are mammals, not fish.

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Bats Are Mammals

Bats are mammals that can fly and nurse their young with milk.

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Spiders Aren’t Insects

Spiders are arachnids, not insects, and have eight legs.

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Insects Have Six Legs

All insects have six legs and three body parts.

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Teeth Enamel

Tooth enamel is the hardest substance in the human body.

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Heart Is a Muscle

Your heart is a strong muscle that pumps blood through your body.

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Human Bones

An adult human has 206 bones.

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Batteries Store Energy

Batteries store chemical energy and can power circuits.

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Electric Circuits

Electricity flows in a closed path called a circuit.

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Simple Machines

Levers, pulleys, and ramps are simple machines that help make work easier.

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Measuring Length

We use rulers or meter sticks to measure length and distance.

Thermometer

A thermometer is used to measure temperature.

Constellations

Constellations are patterns people see in the stars.

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Meteors

A “shooting star” is a small space rock burning up in Earth’s atmosphere.

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Earth’s One Moon

Earth has one natural satellite—the Moon.

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Mars the Red Planet

Mars looks red because of iron-rich dust on its surface.

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Jupiter Is Biggest

Jupiter is the largest planet in our solar system.

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Magnets Have Poles

Magnets have north and south poles; opposite poles attract, like poles repel.

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Sound Is Vibration

Sound travels as vibrations through air, water, or solids.

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Lightning Is Electricity

Lightning is a giant spark of electricity in the atmosphere.

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Rainbows

Rainbows form when sunlight is bent and split by raindrops.

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States of Matter

Matter commonly exists as solid, liquid, or gas.

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Water Cycle

Water evaporates, condenses into clouds, and falls as precipitation in a cycle.

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Clouds

Clouds are made of tiny water droplets or ice crystals floating in the air.

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Photosynthesis Gas Swap

Photosynthesis uses carbon dioxide and water and releases oxygen.

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Plants Make Food

Plants make their own food using sunlight, water, and air in photosynthesis.

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Moon and Tides

The Moon’s gravity helps cause ocean tides on Earth.

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Gravity

Gravity is a force that pulls objects toward each other, like you toward Earth.

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Water Freezing Point

Pure water freezes at 0°C (32°F).

Day and Night

A day happens because Earth spins once on its axis in about 24 hours.

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Earth’s Year

Earth orbits the Sun once every about 365 days, which we call a year.

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The Sun Is a Star

The Sun is a medium-sized star that gives Earth light and heat.

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Bananas Are Berries

Botanically speaking, bananas are berries, but strawberries are not.

Rosetta Stone

The Rosetta Stone helped scholars decipher Egyptian hieroglyphs.

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Water Boiling Point

At sea level, pure water boils at 100°C (212°F).