# Connection between Pressure, Surface Density and Height?

• Whtbrd
In summary, the conversation is about the need for background equations to support the reasoning for a lab experiment involving dropping a basketball and measuring its bounce height. The first part of the experiment determined the ideal pressure for the ball to be 9PSI through a data-logger test. The second part involved dropping the ball on different surfaces with varying densities and a logarithmic equation was derived. The speaker is looking for additional equations that can support the results, particularly for the second part. They mention the possibility of using displacement=Height/(Pressure, Density) and ask for any helpful equations from physicists.

#### Whtbrd

[Mentors' note: moved from technical forums so no template]

Hi All,

Working on a lab write-up, and I need background equations to support the reasoning for my experiment.

To outline briefly, two-part experiment, first part was finding the ideal pressure for a basketball, where I inflated it, dropped it, and used a data-logger to see the height it returned to. This provided me with results that showed 9PSI was ideal, from a test of 8PSI-10PSI (+0.5)

Second part, was using my ideal pressure, dropping the ball on different surfaces, based on their density (g/m^3), this has given me a logarithmic equation, which makes sense, as the higher density, the ball will bounce higher, but won't bounce higher than it started at.

Basically, looking for any supporting equations found by physicists that can prove this should work, particularly for part 2. Guessing it'll look something like displacement=Height/(Pressure, Density), with pressure and density in the denominator.

If anyone has any equations that they think will be helpful, please link to an article on them.

Thanks,

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Whtbrd said:
dropping the ball on different surfaces, based on their density
How can you be sure they don’t differ in other ways that might be more important? Water is denser than wood, but my guess is it would bounce higher off the wood (depending on temperature).