balloons

[soccergirl387]

Are there any experiments for a science fair having to do with balloons that you would suggest? This is for 8th grade physical science.

[agm]

Hi soccergirl387,

1. You could search our project ideas for "balloon", though some results might be fairly tangential to what you have in mind:

https://www.sciencebuddies.org/science- ... deas.shtml

2. To understand what goes on with the gas inside a balloon and the forces that the balloon and (interior and exterior) gas apply to each other, read about the ideal gas law. You could think about how balloons break and how that relates to the properties of what they're made of -- usually latex. Latex is a type of polymer, and the Macrogalleria website is great for learning about polymers:

http://pslc.ws/macrog/maindir.htm

For example, what happens to latex's elasticity when its temperature changes? Since you're interested in balloon animals, are those balloons made of a different kind of latex, processed differently, or are they just a different shape? When you start blowing up one of those long balloons, why is there usually a skinny part left on the end at first instead of the whole balloon expanding at the same rate? I only know the answer to one of these questions -- just trying to get you started thinking.

This sounds like a fun project! My advice as you are reading more is to glance over our science fair project guide, particularly the part about forming a question, and to just take notes about questions you have. Later you can pick out a few of the most interesting ones and think about how to perform experiments to answer each, then choose the one that will enable you to do the most solid experiment with the resources and time you have available.

https://www.sciencebuddies.org/science- ... ndex.shtml

(Also, don't be surprised if a moderator combines this topic with your last one -- it's just so all the experts can follow the evolution of your ideas at a glance and give you the best advice possible.)

Best wishes, and keep us posted on your thoughts,
Amanda

[peteryoung]

Hello SoccerGirl387:

Amanda listed some good references and perhaps you've found some science experiments that would use balloons in some fashion. The following occurred to me and perhaps you and others can think up ways to customize this basic idea.
To slow down probes entering the upper atmosphere of planets such as Mars, one approach is for the re-entering spacecraft to put out inflatable balloons to provide the initial braking forces; parachutes or rocket motors would take care of the final landing phases. The advantages of balloons for this type of application: they take up very little space when unpressurized and they're mechanically simple. To handle the friction and mechanical stresses, a spacecraft "balloon" decelerator would be made from a tough fabric such as Kevlar, but for your purposes, rubber balloons would be much more practical.
For your project, you could blow up balloons to different sizes, then drop them from a reasonable height with a payload attached. You should decide on payload weights, and vary balloon sizes, then measure the descent time.
For background on designing a test of this sort, read through the Science Buddies sections on establishing an experimental hypothesis. If you have enough time, you could try single balloons, doubles, triples, or other combinations.
I think you could have a lot of fun with an experiment along these lines, and also learn a lot about setting up a test --

Regards

Peter Young