READ THIS THEN ANSWER I WILL GIVE U The atmosphere is the blanket of gases that surrounds the planet. It is about 97 kilometers (60 miles) thick. The top may not sound as if it is that far away. But imagine trying to see a baseball game from that distance. It would be almost impossible. It is also difficult to study the atmosphere from far away. Scientists need instruments, or tools, to study the atmosphere.

Temperature And Air Pressure
A thermometer is a device that measures temperature. It was one of the first tools ever used to study the atmosphere. The first thermometer was invented in Italy in the 1590s by Galileo Galilei. A hollow glass tube was placed upside down in water. Cold air made the water rise. Hot air made the water lower. That's because cold air made air in the glass tube shrink, and water would fill up that space. In 1612, another Italian scientist added a number scale so that temperatures could be read.

Illustration of a thermoscope. A tube with a round bulb at the bottom is upside down in water. The tube fills with water. A ruler measure the height of the water. Zoom-in
Image 2. The first thermometer design by Galileo Galilei is usually called a thermoscope. It is a long thin tube with a bulb at the end. The tube is placed in water, which rises through the tube. The water rises into the tube toward the bulb. It reaches different heights at different temperatures. Photo: Getty Images

About 50 years later, Evangelista Torricelli invented the barometer. It measures air pressure. Air pressure is caused by the weight of the atmosphere pressing down in a certain location. When the air pressure is high, the atmosphere is calm. When the air pressure is low, the atmosphere is stormy.

Instruments In Weather Balloons
Instruments like thermometers measure the atmosphere nearby. But what if scientists want to explore the atmosphere where there are no instruments? Scientists use remote sensing instruments. These are tools that can get information from far away.

High in the atmosphere, the temperatures are below zero and the air is thin. Scientists had to make instruments that can work in cold, thin air. One instrument is the weather balloon.

Weather balloons rise into the atmosphere. They carry a radiosonde. This is an instrument that measures temperature, pressure and humidity. That is how much water vapor is in the air. The radiosonde sends this data back to scientists every few seconds. They use this data to create weather forecasts.

A weather balloon can only travel about 32 kilometers (20 miles) up from the surface. High in the atmosphere, the air pressure is very low. The air inside the balloon can take up more space. If the balloon gets too high, it pops. To collect data at higher altitudes, scientists use satellites.

Weather Satellites In Orbit
In the 1960s, NASA put the first weather satellite into space. A satellite is an object that orbits around a planet or moon. Today, weather satellites continuously circle our planet hundreds of miles above its surface. They are one of the best tools for studying Earth. From high above the Earth, satellites are able to "see" atmospheric events around the world. Satellites collect data and pictures and send them from space back to Earth's surface.

Satellites watch many things. They track clouds, lightning and hurricanes. They look for plumes of smoke and ash from wildfires and volcanoes. They take the temperature of the ocean. They see how much snow and ice is melting. Satellites also help scientists study the chemicals in the atmosphere. They measure chemicals such as ozone, air pollution and greenhouse gases.

Radar And Computer Models
Radar is another tool that can study what is happening in the atmosphere. Weather balloons and satellites look at the atmosphere from above. Radar looks from the ground. Radar sends out radio waves. It sees how the waves bounce off objects in the air such as rain and snow. Radar shows where the rain and snow are.

One kind of radar, called Doppler radar, can see where a storm is and tell where it is going. It can tell whether a storm is moving away or toward an area. It can also see if a storm is turning, or rotating. It might be a tornado.

Meteorologists use models to make weather forecasts. These models are computer programs. The program is given data about what is happening in the atmosphere now. It then makes a model of what could happen based on that information