Rockets

November 24, 2012 12:57 am

Rockets body { margin-top:0px; margin-left:0px; margin-right:0px; margin-bottom:0px; padding-left:21px; background-color:#FFFFFF; overflow-y:auto; } .header { height:60px; } .headword { font-family:MS Reference Sans Serif;font-size:26.66667;line-height:26.66667px } .picbutton { width:187px;} .mediabar { width:200px;vertical-align:top;filter:progid:DXImageTransform.Microsoft.Gradient(GradientType=1, StartColorStr=’#FFCC66′, EndColorStr=’#FFFFFF’);padding-left:16px;padding-top:16px; } .sectitle { font-family:MS Reference Sans Serif;font-size:24px;color:#FF7800 } .kidspar { font-family:MS Reference Sans Serif;font-size:19px;color:#000000 } .kidsintro { font-family:MS Reference Sans Serif;font-size:21px;color:#000000 } .MediaTextSpanWidth{ { width:528; } div.mediaTitle { font-size:24px; font-weight:bold; font-family:”MS Reference Sans Serif”; color:#FF7800; } .mediaCaption { padding-top:1px; font-size:19px; font-family:”MS Reference Sans Serif”; color:#000000; position:relative; padding-bottom:4px; direction:ltr; } .mediaCreditUnderMedia { font-size:12px; font-family:”MS Reference Sans Serif”; color:#999999; padding-bottom:2px; direction:ltr; } div.copyright { font-size:12px; font-family:”MS Reference Sans Serif”; } .ktbFootnote { } table.ktb { text-align:left; border:1px solid #47A807; margin-bottom:19px; } caption.ktb { color:#FFFFFF; background-color:#8ACA5A; border:0.75pt solid #47A807; border-bottom:0pt; font-family:MS Reference Sans Serif; font-size:16pt; text-align:left; padding-top:3pt; padding-bottom:3pt; padding-left:5.25pt; padding-right:5.25pt; } THEAD.ktb { background-color:#CDEBAD} .ktbColumn { border-bottom:1px solid #47A807;} .ktbColRow { padding-top:2.25pt; padding-bottom:2.25pt; padding-left:4pt; padding-right:4pt; color:#000000; font-family:MS Reference Sans Serif; font-size:11pt; } TH.ktb { color:#000000; background-color:#CDEBAD; border-bottom:0.75pt solid #47A807; font-family:MS Reference Sans Serif; font-size:11pt; font-weight:bold; } TH.ktbEmptyTH { } tbody.ktb { } #ktbDividerCell { border-top:1px solid #47A807; border-bottom:1px solid #47A807; } .ktbDividerRow { padding-top:2.25pt; padding-bottom:2.25pt; padding-left:4pt; padding-right:4pt; color:#000000; font-family:MS Reference Sans Serif; font-size:11pt; ; background-color:#CDEBAD; font-weight:bold; } .ktbNormalRow { color:#000000; font-family:MS Reference Sans Serif; font-size:11pt; vertical-align:top; padding-left:4.5pt; padding-right:4.5pt; padding-top:2.25pt; padding-bottom:2.25pt; } #ktbEvenRow { background-color:#EFFCD6 } #ktbOddRow { background-color:#FFFFFF } TD.ktb { } TFOOT.ktb { color:#000000; font-family:MS Reference Sans Serif; font-size:8pt; background-color:#8ACA5A; } .ktbFootnoteBorder { height:1px; background-color:#47A807 } .ktbFootnoteRow { padding-left:6px; padding-right:6px; padding-top:3px; padding-bottom:3px; } .ktbFootnote { text-align:left } .ktbSourceRow { padding-left:6px; padding-right:6px; padding-top:3px; padding-bottom:3px; }} .ktbSource { text-align:left } .jtitle_print { font-family:MS Reference Sans Serif; margin-left:24pt; font-size:24; } .kids_ruby_span_print { line-height:32pt; } .kids_ruby_print { ruby-align:auto; ruby-overhang:auto; ruby-position:”above”; } .kids_ruby_text_print { font-family:MS PGothic; font-size:8pt; }

Rockets
You hear a rumble and a roar. A blast of fire shoots out of a big rocket. The rocket heads up into the air. Maybe the rocket is carrying a satellite into orbit around Earth. Maybe the rocket is carrying a probe to another planet!
Only a big rocket can make it into outer space. No other machine is as powerful as a rocket.
WHAT DO ROCKETS LOOK LIKE?
A rocket looks like a long tube. Most rockets have fins on the back end to help them fly straight.
Rockets that carry fireworks can be short, only a few inches long. They are usually made of cardboard.
Rockets that go into space are huge. They are made mostly of metal.
WHAT MAKES ROCKETS GO?
Rockets burn fuel. Many different chemicals can be used as rocket fuel. The burning fuel makes hot gases. The gases blow out of the bottom end of the rocket. The hot gases shooting downward make the rocket go upward.
You can see how a rocket moves by blowing up a balloon. Hold the end of the balloon tightly so the air cannot get out. Then let go. The air rushes out of the opening in the balloon. The air rushing out makes the balloon fly around.
A rocket, like a balloon, has a small opening. The opening in a rocket is called a nozzle. Hot gases blasting out of the nozzle make the rocket go.
HOW DO WE USE ROCKETS?
People use rockets to carry things through air and space. Different kinds of rockets carry different things.
Sounding rockets carry instruments to measure air pollution, rays from space, and weather. Lifesaving rockets carry ropes to ships stranded offshore. Distress rockets signal for help.
The most powerful rockets carry satellites and spacecraft into space. Many spacecraft use smaller rockets called thrusters to move around once they’re in space.
Rockets can also be used as weapons. The rocket weapons are called missiles. Most of the rockets made are missiles.
WHAT IS A MISSILE?
Missiles are rockets that carry bombs. The British used rockets carrying bombs against the United States in the War of 1812. The national anthem of the United States even has a line about the rockets: “And the rockets’ red glare ….”
Guided missiles have steering systems that guide them to destroy their targets. The smallest guided missiles can be carried by soldiers. The biggest guided missiles are huge. They can carry nuclear bombs around the world.
LAUNCHING A MISSILE
Missiles can be launched (fired into the air) from the ground, from airplanes, from ships, and even from submarines. Missiles can also be launched from bombproof underground tubes called silos.
Soldiers on battlefields launch small missiles out of tubes that they can carry on their shoulders. Special trucks carry ground-to-air missiles that aim at airplanes. Special racks underneath fighter planes carry air-to-air missiles.
HOW DO YOU LAUNCH A SPACE ROCKET?
Big rockets are launched from launch pads. A rocket stands on the pad next to a tall tower. The towers have elevators to take workers up and down. Gigantic tractors called crawler transporters bring big rockets or the space shuttle to a launch pad.
Controllers count the seconds before launch as they finish checking everything. “Five, four, three, two, one ….” Bridges that connect the tower to the rocket swing away. “Ignition!” The rocket engines fire. The spacecraft lifts off into the sky.
Firing one rocket does not always provide enough power to send a spacecraft far from Earth. The most powerful rockets often have different stages. Stages are separate rockets stacked on top of each other.
HOW DO ROCKET STAGES WORK?
Rockets headed for space must go really fast, about 25,000 miles per hour (40,000 kilometers per hour). They must go fast enough to overcome Earth’s gravity. Gravity is the force that pulls you back down to the ground when you jump up. Using more than one rocket stage is the best way to go really fast.
The bottom stage fires, uses up its fuel, and drops off. Then the next stage fires. Each stage takes the spacecraft faster and higher. The huge Saturn V rocket that sent Apollo astronauts to the Moon had four stages.
WHO INVENTED ROCKETS?
Chinese people probably invented rockets more than 1,000 years ago. By the end of the 13th century people in Asia and Europe also knew how to make rockets.
American physicist Robert H. Goddard researched new, more powerful kinds of rockets during the early 1900s. A German inventor named Wernher von Braun helped Germany make missiles during World War II (1939-1945). After World War II, von Braun helped the Americans make rockets. The Soviet Union also made rockets. Soviet scientists launched the first satellite into space in 1957.
The United States, Russia, and other countries made bigger and more powerful rockets. Rockets have launched spacecraft to the Moon and most of the planets.
Space engineers are working on better rockets. They are testing rockets that use nuclear power. They are trying to build rockets that get their power from beams of light.
Tags:
shared on wplocker.com