This is a science project book, I will take you deep into the projects of physics, chemistry, biology and explain why the thing which 'happens', happens! There will be a chapter containing science facts between every pair of science project chapters...
Have you ever looked up into the sky and seen not a bird, not a plane, but a hot-air balloon? They are definitely amazing and fun to watch! But enough with this watching, let's make one!
What Do You Need:
Poster board, 3 feet x 2 feet (1 piece).
Scissors.
Scotch tape.
Ruler.
Dry-cleaning bags, dress-size (6). The plastic should be as thin as possible.
Toaster.
What Do You Do:
Fold the poster board in half, lengthwise.
Cut the poster board in half, along the crease from the fold.
Tape the two pieces of poster board together, at their short ends. This should make a long rectangle.
Circle the rectangular piece of poster board around the toaster, so that it leaves about 5 centimeters (cm) of space between the toaster and the paper.
Tape the edges of the poster board together to make a circle or oval around the toaster.
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Trim any extra plastic away from the dry-cleaning bag. For example, some bags have tapered shoulders that leave unused plastic.
Repair any holes or rips in the bag with clear tape. Use as little tape as possible, since the weight of the tape might affect how the balloon flies.
Measure the length of the bag. This is the height of the balloon.
Unplug and clean the toaster if it has a lot of crumbs. It will get hot during the experiments, and the crumbs could start to burn.
Set up the balloon launcher in an area with a high ceiling and no wind.
Place the toaster on a clean, dry surface where you plan to launch the balloons.
Put the poster board ring around the toaster.
Turn the toaster on.
Carefully place a dry-cleaning bag over the toaster.
Hold the plastic bag up so that the hot air can fill it.
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Continue holding and supporting the balloon until it is fully inflated.
If the balloon tips and spills out the hot air, add two sticky notes to the bottom edge, put the sticky notes on opposite sides of the bottom edge of the balloon.
If the balloon continues to tip, adjust the sticky notes until the balloon flies straight up.
What Happens:
A hot-air balloon uses a fabric bag, called a lifting envelope, with an opening at the bottom, called the mouth. Attached to the envelope is a basket, or gondola, for carrying passengers. A burner is mounted below the mouth of the balloon, and injects a flame into the envelope, heating the air within.
Hot-air balloons are able to fly because air expands (grows larger so that it takes up more room) when it is heated. This is similar to the way popcorn kernels expand when you heat them. But instead of "popping open" like the popcorn kernels, some of the air in the hot-air balloon is pushed out of the opening in the bottom of the balloon as the air expands. In the end, there is less air inside of the balloon (because some has been pushed out), but it still takes up all of the space in the balloon because it has expanded (grown larger). This makes the air inside the balloon lighter than the surrounding air on the outside of it. The balloon has a buoyancy (a lifting force) equal to the weight of air that has been pushed out of the balloon as the air expands. The balloon is able to leave the ground when the weight of air that has been pushed out of the balloon equals the weight of the balloon itself, plus the expanded air inside of the balloon.
The buoyancy of the balloon is an example of Archimedes' principle. His principle states that an object (in this science fair project, the balloon) immersed in a fluid (the surrounding air), is buoyed up by a force that is equal to the weight of the fluid that is replaced by the object.
This is a PG project.
Caution:Be careful not to melt the plastic bag. Be cautious around the cord, so you don't trip. Also, handle the toaster with much care. Have a volunteer to help you if it's possible.
Do not forget to tell me about your results. Also if you like the project, vote and give feedback please!
