Rocket Experiments

You can demonstrate the principle of action-reaction many ways. The simplest way is to blow up a balloon and let it go. It will zoom around the room as the compressed air inside rushes from the mouth of the balloon (see diagram below). It will also make a funny sound.

You can create a more controlled flight by taping a soda straw to your balloon and threading a string through it. Tie the string to a pair of supports as far apart as possible. Blow up the balloon and release it at one end of the string.

You can construct a rocket car that demonstrates the principle of rocket propulsion: for every action, there is an equal and opposite reaction.

YOU NEED:

A large Styrofoam tray such as those used in the supermarket to package vegetables, 4 pins, 1 bendable drinking straw, 1 balloon, cellophane tape, scissors, compass, marker for drawing on plastic, ruler, AND measuring tape.

1. Draw the parts of your car with a ruler and compass on the Styrofoam tray. You will need a large rectangle, 4 large circles for the wheels, and 4 small cir-clesfor the hubcaps. Cut out the parts.

In a balloon, the inside pressure is the same in all directions. If one end of the balloon is opened, the pressure becomes unequal. The reaction of the escaping air causes the balloon to shoot in the opposite direction. The same thing occurs in a rocket: the unequal internal pressure causes the rocket to shoot in the direction opposite its exhaust.

In a balloon, the inside pressure is the same in all directions. If one end of the balloon is opened, the pressure becomes unequal. The reaction of the escaping air causes the balloon to shoot in the opposite direction. The same thing occurs in a rocket: the unequal internal pressure causes the rocket to shoot in the direction opposite its exhaust.

2. Blow up the balloon, and let out the air (this will make the balloon easier to blow up next time). Pull the opening of the balloon over the short end of the straw, and fasten it in place with cellophane tape. Fasten the long end of the straw onto the rectangular Styrofoam tray, as it is in the diagram below.

3. Push the pin through the middle of the hubcaps on each corner of the Styrofoam tray.

4. Blow up the balloon through the straw. Hold the end of the straw closed by squeezing it between your thumb and fore finger, and put the car on the ground. Start your rocket car by letting go of the straw.

EXERCISES:

1. Measure the distance your car travels.

2. What can you do so that the car will go faster and farther and keep its course? Try out your suggestions, measure the distances traveled, and note the results. Which changes have the greatest effects on the results?

3. Organize a car race with your friends.

balloon tape straw tape straw

pins styrofoam cart and wheels pins styrofoam cart and wheels

A rocket car like this one demonstrates the principle of rocket propulsion.

The War of 1812

During the War of 1812 (1812-1815), the British virtually destroyed the city of Washington, D.C., and then set their sights on Baltimore, Maryland. While Baltimore was attacked from land, ships of the British navy were poised to strike Fort McHenry and enter Baltimore Harbor. At 6:30 a.m. on September 13, 1814, these ships began a twenty-five-hour bombardment of the fort.

Congreve rockets whistled through the air and burst into flames wherever they struck. (Many of the rockets missed their targets or fell short. They landed in the waters of Chesapeake Bay, where their remains probably still lie on the bottom.) All through the night, however, the U.S. soldiers held the fort, refusing to surrender. At 7:30 on the morning of September 14, the British admiral ended the bombardment and his fleet withdrew.

Throughout that terrible night, the U.S. soldiers flew an enormous flag over the fort. They wanted to show the British invaders that they had not surrendered. Waving proudly over the fort, the banner could be seen for miles—even as far away as a ship anchored 8 miles (13 km) down the river. This is where a U.S. lawyer named Francis Scott Key had spent an anxious night watching and hoping for a sign that the city—and the nation—might be saved. He wrote a poem to describe what he had seen that night and, in doing so, immortalized Congreve's rockets:

Oh! say, can you see by the dawn's early light, What so proudly we hailed at the twilight's last gleaming, Whose broad stripes and bright stars, through the perilous fight, O'er the ramparts we watched

When the U.S. national anthem refers to "the rockets' red glare," it is describing the British attack on Fort McHenry in 1814 (above). Masses of Congreve rockets were launched from specially equipped rocket boats. The rocketeers wore heavy leather clothing to protect them from the blast of the rockets' takeoff.

When the U.S. national anthem refers to "the rockets' red glare," it is describing the British attack on Fort McHenry in 1814 (above). Masses of Congreve rockets were launched from specially equipped rocket boats. The rocketeers wore heavy leather clothing to protect them from the blast of the rockets' takeoff.

were so gallantly streaming? And the rockets' red glare, the bombs bursting in air, Gave proof through the night That our flag was still there. Oh, say, does that star-spangled banner yet wave O'er the land of the free and the home of the brave?

Was this article helpful?

0 0
Meditation Mastery Breath Watching

Meditation Mastery Breath Watching

Discover How Breath Watching Meditation Turned My Mind From Cluttered To Laser Focus. You Can Get More Things Done When You’re Focus And Aware Of Your Mind.

Get My Free Ebook


Post a comment