# Build

## Instructions

• 1

Here are some of the materials that you can use

• cardboard tubes
• copier paper
• 2 Mylar balloons with a ribbon (helium-filled) (you can find these at party stores, florists, dollar stores, drug stores, or supermarkets)
• paper clips (small)
• rubber bands
• scissors
• 2 sheets corrugated cardboard (approx. 11 x 17 inches [28 x 43 cm]) (corrugated cardboard has grooves in the middle, like a cardboard shipping box)
• tape (clear and duct)
• 2

• Have paper and a pencil ready to write down ideas and sketches as you design.
• Work in an area away from windows or doors that might have drafts or breezes.
• Think about things that are streamlined, or longer rather than wider, to go through the water or the air like a blimp. (Airplanes, birds, fish, submarines)
• Drop a sheet of paper on the floor, making sure the flat side is perpendicular to the floor. Then drop it with the flat side parallel to the floor. Which way does the paper fall more slowly to the floor?
• TIP: An object will fall more slowly when its flat or wide side is parallel to the floor because the object has more drag, or force, that that is resisting its movement.
• 3

• Why is a blimp’s shape longer than it is wide?
• Why do people use blimps? (Film sporting events, TV broadcasts from the sky, search-and-rescue missions, observe wildlife)
• How does a blimp keep from floating upward?
• TIP: An object that has to travel long distances through the air has to be longer than it is wide so it can slice through the air.
• Air is denser, or heavier, than helium. The air pushes the helium aside and makes an upward force, or pressure, called a buoyant force. This pushes the balloon up, but when it reaches a point where the density of the air outside the balloon is equal to the density of the helium inside the balloon, there is no longer a buoyant force and the balloon stops rising and hovers in one place.
• 4

• What makes a balloon hover, or float, in one place?
• Why do people use airships or blimps instead of airplanes?
• How wide will you make your blimp?
• How will you control the direction it moves in?
• TIP: An airplane uses a wing with an engine to keep it in the air, but an airship or blimp uses gas, such as helium, to keep it in the air. This lets the airship fly and hover without using fuel or energy.
• 5

Look at the materials

• How will you make your blimp fly in a straight path?
• What materials will you use to make your blimp?
• What materials do you have to make a gentle launch for your blimp?
• What materials will you use to power the launch?
• 6

Design and build the blimp

• Decide what length you want to make your blimp.
• Think about how you will attach the balloons.
• TIP: To help your blimp travel in a straight path, lengthen the distance between the balloons. This is called the axis of rotation. If the axis of rotation is short, the blimp is more likely to spin and get off track.
• 7

Test the blimp

• Let your blimp go to test if it can hover in one place.
• Add or take away weight if it rises to the ceiling or falls to the floor.
• Retest. Continue until your blimp hovers.
• TIP: If you want your balloon to hover, it needs to have neutral buoyancy. This means the force pulling down (gravity) has to be equal to the force floating up (lift).
• TIP: If your blimp won’t hover, try adding or taking away weight to help balance it. A small paper clip or piece of ribbon can be just enough weight to make a balloon too heavy to hover.
• 8

Design and build the launching station

• Decide how you will gently launch your blimp.
• Think about how you can create air pressure to push your blimp up.
• Choose your materials and build the launching station.
• 9

Design and build the launching station (continued)

• Decide how you will power the launching station to set your blimp in motion.
• Choose the materials and attach the power source.
• TIP: When you stretch a rubber band, you are giving it potential energy—which is stored energy. When the rubber band snaps back, it transforms the potential (stored) energy into kinetic energy—or motion energy.
• 10

• Decide on the location for your blimp’s launching station. Make sure there is nothing in the way of your blimp having a smooth flight.
• Place your launching station in the location.
• 11

• Let it fly!
• TIP: If your blimp doesn’t fly in a straight path, try adding fins to help it glide straight ahead.
• TIP: Engineers always review and modify their ideas as they go along. It’s part of the design-build-test process. Testing reveals things about a design and the materials. As you go along, record any changes you make to your design and the effects they have.
• 12

Did you know?

• The 580 Bullet Takes to the Skies
Recently, people have been showing a renewed interest in the use of airships. For example, in 2010, the model 580 Bullet airship took to the skies. At 235 feet (72 m) in length, the 508 Bullet is one of the world’s largest inflatable aircrafts.

The airship, which took over 6 hours to inflate, is made from a super-strong plastic material called Kevlar. Kevlar is a tough, thin material that is more than five times stronger than steel! The 580 Bullet can hover over an area for up to a week at a time, which makes it useful for monitoring natural and man-made disasters such as forest fires, hurricanes, or oil spills. But disasters aren’t the only use for the 580 Bullet airship; it can also be used to carry heavy cargo to remote areas or to bring a group of sightseers over a dangerous tourist area. So, keep your eyes open because the sight of a large airship moving across the sky may become more common in the near future.
• 13

Try this next!

• Streamline your blimp. Modify your blimp by making a longer or shorter axis of rotation. Keep record of the effects this has as you fly your blimp.