Boyle's Law Experiment: Data Analysis

Analysis of data obtained in the Boyle's law experiment (video here: • Boyle's Law Experiment... ) in which the relationship between gas pressure and volume at constant temperature for a fixed mass of gas is investigated. Boyle's law is one of the key foundations of the ideal gas law and so this experiment is relevant for GCSE science, A-Level physics and A-Level chemistry.
You can download the worksheet to try the analysis yourself - great for learning independently at home: physicshq.wixs...
Relevant concepts: Boyle's law, gas laws, ideal gas law, gas pressure, gas volume, direct proportionality, inverse proportionality, and testing for proportionality.

[@mcneelynorman1]

This is my second year teaching and this was very insightful. Thank you.

[@zahraqamar8466]

We doing this on Thursday in school and have questions based on it 😭 this is gonna help me loads, thank you

[@PhysicsHQ]

Great! Hope it goes well on Thursday.

[@MiguelCancelaMunoz]

Hello, great video. One question, why isn't atmospheric pressure added to the pressures? I understand that it is a manometer and only indicates relative and not absolute pressure of the gas.

[@jackalfrosti3591]

What sort of improvements can be made to this experiment to get more accurate results?

[@PhysicsHQ]

Improve resolution (precision) of volume scale. Monitor temperature of the air column to ensure changes occur at constant temperature. Repeat experiment to check if results are consistent. Measure p and V over an increased range.

[@FanaKumalo-fv8gk]

What precautionary measure was taken to ensure that the temperature of the gas remained constant during the experiment

[@PhysicsHQ]

I reduced the pressure slowly. This reduces the friction at the valve which can be a notable source of temperature change.

[@saieshengovender7109]

thanks a lot sir

[@PhysicsHQ]

You’re welcome, all the best with your studies

[@Kholofelo-ok4nr]

Sir what are simple four steps procedure to follow when performing this experiment

[@detective2027]

Thanks a lot I finally found it

[@padoody324]

0:09 is there a specific name for the apparatus with the volume scale and oil column?

[@PhysicsHQ]

I’m not aware of one aside from “Boyle’s Law apparatus”. That’s how we’ve always referred to it

[@PhumudzoMudau-g5w]

Unde boyles law experiment Why is sufficient time allowed before the corresponding reading of volume taken

[@krm-2196]

is there a way to calculate the uncertainty of the y - axis of graph p against 1/v ?

[@PhysicsHQ]

I would calculate the uncertainty of the gradient since it is the gradient that would be used to calculate a quantity (like R or n). I’ve made a video on how this is done: kzbin.info/www/bejne/rF61gKl6a52Ur9k

[@charliewakefield612]

how to calculate no. moles of gas of the sample using the gradient of the graph p against 1/v ?

[@PhysicsHQ]

Graph has x variable = p y variable = V⁻¹ Relevant equation: pV = nRT Rearranged equation to match axis variables: V⁻¹ = (nRT)⁻¹ p Comparing this equation to y = mx + c yields: gradient = (nRT)⁻¹ So if the temperature (in K) was known we could determine n as follows: n = 1/ (gradient × RT)

[@gcasello494]

@@PhysicsHQ hold on, when you say y variable, do you mean y axis? it shows on your graph that your y axis is V^-1 so just confused, thank you

[@PhysicsHQ]

Good spot. Yes I did state it the wrong way around in the above comment. V⁻¹ is the y-variable. I’ll edit the comment.

[@lesegomochai7841]

I don't understand

[@conallboyle3210]

why don't you get some experiment questions on this and show how to do the calculations

[@PhysicsHQ]

HI, thanks for sharing your thoughts. I have previously published a video that explains these calculations - kzbin.info/www/bejne/rpe5lneXns6Betk (though I think it needs redoing). I do also have a worksheet that guides students through the manual calculations and their interpretation. In your opinion do those things accomplish this suggestion?

[@Mojo_JoJo-r]

where can i download the application hes using

[@PhysicsHQ]

The application is Numbers iOS: apps.apple.com/gb/app/numbers/id361304891 macOS: www.apple.com/uk/numbers/

[@siphikam1200]

can I get the application in android that you are using

[@PhysicsHQ]

The application I use (Numbers) is not available on Android. But Google Sheets is available on Android and can do everything I do in this video (and more).

[@nathanngqwebo2108]

That's some sexy Excel work.

[@PhysicsHQ]

If there’s one thing I can do pretty well it’s spreadsheets.

[@helenma9154]

What does the variable 'k' represent?

[@PhysicsHQ]

If the "k" in question is the "k"in the inverse proportionality relationship (p = k/V) which is the empirical relationship (i.e. the relationship that comes from the experimental data) then we can compare that with the ideal gas law: pV = nRT, and k = nRT. Since the direct proportionality relationship does not explain the data the "k" in that relationship is not a valid constant. Does that make sense?

[@harisban6742]

Thank You Sir 🙏🙏🙏

[@PhysicsHQ]

You’re very welcome. All the best with your studies.

[@PhakamileNcube]

We can't see your values your screen is far

[@fauza4679]

🤭ur handsome. Oh thanks i understand .

[@PhysicsHQ]

Happy to help! Thanks for the compliment. All the best.