AR34 202 W  Why Does It Rain?

The sun shines brightly on lakes, rivers, and oceans. Its heat warms the water. When water gets warm, it changes into water vapor. This is called evaporation. The water vapor is light, so it rises up into the sky. High in the sky, the air is cooler. The water vapor cools down ...

AR34 193 W  How Does a Rainbow Form?

After it rains, you might see a rainbow in the sky. A rainbow is made by sunlight and raindrops. It only happens when the sun shines while it is still raining or just after the rain. The sunlight looks white, but it is made of many colors. When sunlight passes through raindrop...

AR34 195 W  Why Does Thunder Happen?

On rainy days, you might hear a loud sound in the sky. That sound is called thunder. Thunder happens during a storm, when there is lightning. Lightning and thunder come from the same thing—electric energy in the clouds. Inside a storm cloud, tiny pieces of ice and water ...

AR34 216 W  Why Does It Snow?

Snow falls from the sky just like rain, but it is cold and white. Snow comes from clouds, just like rain does. But for snow to fall, the air must be very cold. When the air is below freezing, water turns into ice. Inside a cloud, there are tiny drops of water. If the air is co...

AR34 201 W  How Does a Typhoon Form?

A typhoon is a very strong storm. It brings heavy rain and strong winds. Typhoons form over warm ocean water. They only happen in some parts of the world, like the Pacific Ocean near Asia. The sun heats the surface of the ocean. The warm water makes the air above it hot. This ...

AR34 199 W  Why Does the Wind Blow?

Wind is moving air. We can feel it on our skin, see it move trees, and hear it whistle. But why does the wind blow? Wind starts because of the sun and the way it heats the Earth. The sun warms the Earth, but not all places are heated the same. Land heats up faster than water. ...

AR34 206 W  Why Do Seasons Change?

We have four seasons: spring, summer, fall, and winter. Each season feels different. Sometimes it is hot, sometimes cold. But why do seasons change? The answer is Earth¡¯s movement around the sun. The Earth moves in two ways. It spins like a top. This spinning gives us day and...

AR34 205 W  How Do Clouds Form?

Clouds float in the sky and come in many shapes and sizes. But how do clouds form? The answer begins with the sun and water. The sun heats up water in lakes, rivers, and oceans. This warm water changes into water vapor. The vapor is a gas that rises into the sky. This is calle...

AR34 187 W  How Is the Weather Forecast Made?

Every day, people check the weather to plan their day. But how do we know if it will rain or be sunny tomorrow? This is called a weather forecast. A forecast tells us what the weather might be like in the future. Weather forecasters use tools to study the air. They use thermom...

AR34 183 W  Why Does Sunlight Feel Warm?

When the sun shines, we feel warm. But why does sunlight feel warm on our skin? The answer is energy. The sun gives off light and heat energy that travel through space to Earth. The sun is a huge ball of hot gas. It makes energy deep inside through a process called nuclear fus...

AR34 188 W  How Does Hail Form?

Hail is a type of frozen rain. It falls from the sky like small balls of ice. But how does hail form? It happens inside big storm clouds, especially during strong thunderstorms. Inside these clouds, the air moves up and down very fast. When raindrops are carried high into the ...

AR34 186 W  Why Does Fog Form?

Fog looks like a cloud near the ground. It makes it hard to see far. But why does fog form? Fog is made of tiny drops of water, just like clouds in the sky. Fog happens when warm, moist air touches cool ground. The air cools down quickly. When it gets cold enough, the water va...

AR34 196 W  How Does Lightning Form?

Lightning is a big flash of light in the sky. It happens during storms and is very powerful. But how does lightning form? The answer begins in storm clouds. Inside a storm cloud, small pieces of ice and water move around. They bump into each other and create electricity. The t...

AR34 190 W  Why Are Thunderstorms Dangerous?

A thunderstorm is a strong weather event with lightning, thunder, heavy rain, and sometimes strong winds or hail. While it may look exciting, a thunderstorm can be very dangerous. One danger is lightning. Lightning can strike trees, houses, or people. It can cause fires or ser...

AR34 190 W  What Are Natural Disasters?

Natural disasters are big events in nature that can cause harm to people, animals, and the Earth. They happen suddenly and can be very dangerous. There are many types of natural disasters. One type is a storm, like a hurricane or typhoon. These storms bring strong winds, heavy...

AR34 204 W  How Does Temperature Change?

Temperature tells us how hot or cold something is. But temperature is not always the same. It changes throughout the day, during the seasons, and in different places. Why does this happen? The sun is the main reason for temperature change. During the day, the sun shines on the...

AR34 177 W  Why Do Wildfires Happen?

A wildfire is a big fire that spreads quickly in forests or grasslands. Wildfires can burn trees, plants, and even homes. But why do wildfires happen? One reason is dry weather. When there is no rain for a long time, trees and grass become very dry. Dry plants catch fire easil...

AR34 186 W  How Do Earthquakes Happen?

An earthquake is when the ground shakes. It can be small or very strong. But what causes the ground to move? The answer lies deep under the Earth¡¯s surface. The Earth is made of big pieces called tectonic plates. These plates fit together like a puzzle. They move very slowly,...

AR34 179 W  What Is the Difference Between Weather and ...

People often talk about the weather and the climate, but they are not the same thing. What is the difference between weather and climate? Weather is what is happening outside right now or in the next few days. It includes temperature, rain, wind, clouds, and sunshine. For exam...

AR34 177 W  How Do We Observe the Weather?

Observing the weather means watching and measuring what is happening in the air. Scientists called meteorologists use many tools to do this. These tools help them understand and predict the weather. A thermometer measures temperature. A barometer checks air pressure. An anemom...

AR34 201 W  What Is Ultraviolet (UV) Light?

Ultraviolet light, or UV light, is a type of light that comes from the sun. We can¡¯t see it with our eyes, but it is still there. UV light is stronger than the light we can see. The sun gives off many types of light. Some of it we can see, like sunlight. Some we cannot see, l...

AR34 192 W  Why Do Heat Waves Happen?

A heat wave is a period of very hot weather that lasts for several days. It can make people, animals, and plants feel tired or even sick. But what causes a heat wave? Heat waves happen when hot air stays in one place for a long time. Usually, air moves and spreads heat around....

AR34 197 W  Why Do Clouds Move?

Clouds move because of the wind. Even though they look heavy, clouds are made of tiny drops of water or ice that float in the air. These drops are light enough for wind to carry them across the sky. The wind in the atmosphere moves in different directions and speeds. High in t...

AR34 157 W  What Do Weather Satellites Do?

Weather satellites fly high above Earth. They go around the planet many times each day. These satellites take pictures of clouds, land, and oceans. They help scientists know what the weather is like. Some satellites look at big storms. They watch how fast the wind blows. They ...

AR34 161 W  How Does a Snowstorm Happen?

A snowstorm happens when a lot of snow falls with strong wind. It makes it hard to see and very cold. But how does it start? First, the air must be cold. Clouds must have enough water. When the air is cold enough, the water in the clouds turns into snowflakes. Then, wind bl...

AR34 163 W  Why Are Tsunamis Dangerous?

A tsunami is a very big ocean wave. It is not like a normal wave. A tsunami is much stronger and faster. But why is it so dangerous? A tsunami usually starts after an earthquake under the sea. The earthquake moves the ocean floor. This pushes water up and makes big waves. The ...

AR34 155 W  How Does Nature Heal Itself?

Nature is strong. Even after fires, floods, or storms, nature can heal. But how does it do that? When a forest burns, trees and plants may be gone. But after some time, small plants begin to grow again. Seeds in the ground start to sprout. Animals slowly come back. The forest ...