Hot Air Balloon Science Project - Creating hydrogen and examining why balloons float in air.
Science Fair Project Experiment: How Does a Hot Air Balloon Stay in the Air?
Why do you think that the explanation given or the airplane remaining in the air will not account for the buoyancy of a balloon? Since we have learned that air has weight we may compare the floating of objects in air with the floating of objects in water. You know from experience that objects like iron and stones, that are heavier than water, will sink while cork and wood, which are lighter than water, will float.
The same is true of things in the air. Cork and wood and most things we know of are heavier than air and will not float in it. A balloon, however, is lighter than air and therefore will float in it.
We know that air pressure is exerted in all directions. The air under the balloon, therefore, is pushing it upward and the air above it, is pushing it downward. If the balloon weighs the same as
air it will not be pushed either upward or downward. If, however, the balloon weighs more than an equal volume of
air, will the downward or upward pressure be greater? Questions Commonly Asked by Science Fair Judges for Air Pressure and Weight: Explain Air Weight: If the balloon weighs less than the air that it displaces, which pressure will be the greater?
Explain: Why a balloon does not continue to go up until it reaches the top of the atmosphere? Balloons and dirigibles must be filled with a gas much lighter than air. Hydrogen gas, which is about 14X times lighter than air, has been the gas generally used. The use of hydrogen for filling balloons may be shown by making soap bubbles with it.
Experiment for Air Balloons Make sure you get an adult to do this experiment with you! Hydrochloric acid will burn your skin and damage eyes. Proper safety equipment should be worn such as googles, gloves and a lab coat. Make hydrogen by setting up the apparatus and pouring hydrochloric acid through the tube with the
enlarged top (thistle tube) over the pieces of zinc in the flask. By means of a rubber tube attach the stem of
a clay pipe to the tube which carries the gas from the flask. Dip the bowl of the pipe into soapsuds. Shake off the bubbles into the air as they are formed and note their behavior. Touch a bubble with a match and observe what happens.
A new gas (helium) which is found in considerable quantities mixed with the gas of some natural gas wells is now being used. It is somewhat heavier than hydrogen although much lighter than air. The great advantage is its use is that it will not burn, whereas hydrogen does.
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