A-level Physics Core Practical: Finding a value for g using a free fall method

[@GTChow]

Best video on this practical on the internet hands-down. Great work!

[@juliahicksfav]

When he switched places with the professor to let her perform the experiment. This guy is wholesome af.

[@robertserram9219]

He's a beta, pretty sure her wife has some boyfriends.

[@artemisl3506]

@@robertserram9219 ??????????? Right...

[@STAA.R05]

@@robertserram9219how do you know?

[@PhysicsOnline]

That's a fantastically well produced video. Are you planning to cover all the core practicals for the practical endorsement?

[@JonathanSanderson]

+A Level Physics Online Short answer: yes, that's the plan. We're seeking funding support for the full set, but it looks like we've enough to at least make a start. Thanks for your kind words!

[@PhysicsOnline]

+Jonathan Sanderson Will they be aimed at teachers or for the students?

[@JonathanSanderson]

+A Level Physics Online As with our previous films, they're aimed primarily at teachers. That said, many teachers report using them with their students, often for revision purposes.

[@janetseymour6270]

These videos are a great resource for the A 2 students in preparation for the exam. Thank you

[@Valkriecain99]

Aw I liked this. I did the gravity experiment a couple of days ago and was researching general physics resources when I found this. Very good points that teachers fail to share-not because they're incompetent, but because students are meant to be doing practicals with minimal support. So this is quite useful for students, and I will be checking back during my next practical to see if I can get any more guidance. I quite liked the friendly laid back atmosphere of the video. Thanks!

[@othcortes1715]

The last one which used magnet switch and a mechanical switch at the bottom, in my own opinion, can give precise signal to the timer. Great work of physics to share with.

[@jenniferwilson5379]

i really enjoyed this and found it easy to learn from. Plus very wholesome makes me love physics all over again

[@awolgeordie9926]

Excellent. Just did this in class today. Manually. I teach CIE A Level Maths and Physics in Thailand but originally hail from Geordieland.

[@richardneedham9345]

As you point out, dropping a ball through two light gates is not a perfect method for this investigation. 'Better' data can be collected by using a rectangular object rather than a sphere, to ensure the light beam is interrupted by the same point on the falling object. A transparent ruler with a strip of black insulation tape makes a good interrupt card. When using light gates it is more economical, and it speeds up the activity, if a single light gate is used with a double interrupt card (such as a transparent ruler with two strips of black tape). Most data logging manufacturers sell proprietary interrupt cards, although these may have other names such as a 'picket fence'.

[@stustjohn]

Great video. Impressed that you got Daniel Craig to present the electromagnet/trap-door switch part! ;-)

[@Syiepherze]

Are you sure that wasn't Putin?

[@DennisChangweKunda]

Brilliance at the core

[@fawazsm]

great video ... and by the way those were hell of a quick mental calculations !!! ;P

[@melodykamil]

That was so helpful. Thank you very much!

[@dartplayer170]

The correct explanation of why to use the g-ball is that it is more consistent and eliminates human systematic errors in reaction time of manually using a stopwatch. The measurement error is virtually the same. This technique can give about 0.3m/s2 error on 1 measurement which is confirmed by the example here 0f 9.6m/s2. Better results could be attained with a millisecond timer giving 3 significant figures as the error in height is not really contributing to the total error with a 1/100s clock.

[@vg6761]

The y-axis variable can even be 2s, that way the gradient will = g without later multiplying it by 2.

[@nishikantprasad7825]

Incline plane method could also be a way to extract g

[@mukongtangwa2984]

So cool. I had a lot of fun watching that

[@SkyDarmos]

The freefall acceleration depends on the chemical composition. So they can do real research if they measure precise enough and use different materials.

[@Ethanjg]

This is an awesome video. When will another video be released?

[@JonathanSanderson]

We've recently recorded three more films in this series, but it's hard to say when they'll appear; they need to be edited, then signed off by everyone involved. So: a few weeks.

[@Ethanjg]

+Jonathan Sanderson Awesome, that's good to hear :)

[@beigeboi_7714]

Thank you, Alom

[@gkpgeo]

Can we use for measuring for accuracy of 10 micro gals resolution?

[@MohammadSalman-zq2rv]

sir i dont know how u decide the y axis the x axis and the gradient by rearranging equations like the one u did where s was on y axis and t^2 on the x axis and then gradient aswell.Plz make a video teaching how we can do this.

[@asifmahmoud126]

I have the same problem

[@arrushc7029]

If you re-arrange the equation s = ut + 1/2 at^2 to find for a or you can say g, the x-axis and y-axis would produce the same output: s = ut + 1/2 at^2 s - ut = 1/2 at^2 2s - 2ut = at^2 2s = at^2 + 2ut 2s = t (at + 2u) 2s / t = at + 2u Hope this helps :)

[@arrushc7029]

Furthermore, this has to be graphically similar to the equation of a line: y= mx + c. In this case it does hence the equation in the video is correct

[@MyNameIsShobzy]

Why isn't there this for bio + chem :(

[@NUSTEM]

We (Alom and I) have made a series of films in this style over the last few years. Most of them are physics, but a few were biology and chemistry. The ones which are publicly-available are here: nustem.uk/activity/a-level-physics-required-practicals/, and we continue to push for the remaining films to be published on KZbin - they're currently trapped at the National STEM Centre website and a few other place. Unfortunately, we don't have complete control over all the films.

[@SkyDarmos]

A robotic release mechanism should be the best choice. I hope I can find that somewhere.

[@gowridharshini7010]

May I please know why where the heights not considered as negative values? since the drop is a negative direction?

[@carultch]

It is arbitrary what direction we consider to be positive vs negative. Since g is positive unless context and coordinate system requires otherwise, then if it is my choice, I would assign downward as positive, and y-position final as zero, and each of the initial positions as y0 in y = y0 + v0*t + 1/2*g*t^2.

[@saketpanigrahi]

You cn measure g by the help of formula T=2(PI) (L÷g)^1÷2. You need a thread and a (mass) object. In zero budget. I get 9.9 by this techmique but you can measure it more precisely

[@NUSTEM]

Ah, I remember doing that as my first practical lab at university…. :-) More importantly, we have a film about this, too: kzbin.info/www/bejne/h3azZIqDobZ5o80

[@carultch]

@@NUSTEM Would Atwood's machine qualify for teaching an experimental way to determine g, for the A-level program? That was a historical method, where he used pulleys and counterweights to slow down the kinematics, to reduce the impact of reaction time.

[@elliotguest6765]

Who else is here because of Hazel

[@gideonboulton]

At 5.16, it would have been great to see some error bars, and look at the range of values of g you could get - but I suppose you have have a limited amount of time really. Great initiative though.

[@carultch]

I was able to get g=9.77m/s^2 with the g-ball, when the accepted value at my location is 9.803 m/s^2, using half meter intervals up to 4 meters. My closest data point to the accepted value came with a drop height of 2 meters. To high, and air drag becomes significant. Too low, and the resolution of the timer can't get enough precision.

[@MohammadSalman-zq2rv]

the best video ever

[@NNY-q6i]

very good video thank you

[@SkyDarmos]

The problem with a magnetic release mechanism is that it only works for balls that are magnetic. Iron and steel are magnetic, but most metals are not magnetic.

[@ibraheembaloch9772]

what is that ball called ?/???//

[@JonathanSanderson]

Notes to go with the film are posted here: nustem.uk/activity/measuring-g/ …which I hope will answer your question.

[@ibraheembaloch9772]

can you tell me about an experiment to calculate young modulus

[@ch.usmanzafar3648]

best video

[@mr.ahmedjama2589]

Pushin P my guy

[@markkeown9532]

More data dose not mean that you will get closer to the correct value. Attention to detail will. Now is the height value that you are using - the ruler value less the diameter of the ball? And 0, 0 is a good data point why not use it.

[@lucabarnes9844]

yo

[@SkyDarmos]

Taking the average is a completely wrong approach for this type of experiment.

[@robertserram9219]

3:58 BETA male