Watch gravity pull two metal balls together

EDIT: I want to address the comments that say gravity isn't a force, it's the curvature of space time. There's an interesting philosophical point here. The way I think of it is this (I'm not the first to say this but I can't remember who was): physics just gives us models for how the univers works. None of them are "true" but some of them are useful. Newton's model of gravity that describes it as a force is really useful. It doesn't work in certain circumstances. Einstein's model, that describes gravity not as a force, works in more circumstances but is more cumbersome. You pick the mode that best suits what you're doing. In this vide Newton's model is the most appropriate in my opinion. So talking about gravity as a force is perfectly reasonable. Like, imagine being in a physics lab with some springs and pulley or whatever, and you're trying to balance the forces, and every time you mention the force of gravity, someone pipes us and says "I think you'll find gravity isn't a force". That person is unhelpful. Other commenters are saying gravity isn't a force for another reason, which I believe is related to a non spherical model of the earth that they believe in. We can safely ignore those comments. Here's a fun fact: if you scaled down the earth and moon system until the earth was the size of a bowling ball (keeping the density the same), it would still take the moon 27 days to orbit the earth. This is true in general. Like if you scaled down the ISS as well, that would take the same 90 minutes to orbit as it does now. It's true at any scale, not just bowling ball scale! The sponsor is Brilliant: Visit www.brilliant.org/stevemould for 30 days free access. The first 200 people will get 20% off an annual premium subscription.

I’m glad you showed your homemade experiment even though it didn’t work. That took balls.

Great job, Steve! 10% error is typical for what physics majors get when they do this lab experiment using the 2nd apparatus you used.

Remember folks, an experiment with a failed result is still an successful experiment! It's very important in science to not hide the mistakes, but to document them throughly and try to understand the failure. Great video

In my first year at university physics, we did the exact same Cavendish experiment you did to measure G, laser pointer and all. By sheer statistical wonder, despite the extreme finickyness of the experiment, me and my lab partner somehow got the value nigh-bang-on at 6.68*10^-11. The professor simply didn't believe we were that close until he looked at our measurements directly. He said it was the first time he'd seen that anyone measured it to within 0.02*10^-11 accuracy. But then when we calculated the error margin on our measurements, it turned out we had a margin of error of nearly 10x that...

A spring “oioioing” is the technical term

"Other commenters are saying gravity isn't a force for another reason, which I believe is related to a non spherical model of the earth that they believe in. We can safely ignore those comments." So elegant:)

Concerning Mr Lund's experiment : I looked up for common impurities in crude, unrefined lead. I found it typically contains measurable amounts of 6-7 other metals, including up to 1% of nickel. Nickel is ferromagnetic. Could there be some magnetic interaction from that?

We did this experiment in a physics lab many years ago using a small mirror attached to the center of the horizontal bar so we could use a light beam to more accurately observe the deflection, noting the angle every minute or so to make a graph. It took several hours. When it was finished we found it was a damped oscillation as expected, but there was a moment when the amplitude increased instead of continually decreasing. We later found out that a small earthquake had occurred during the experiment.

Mould's Law: a stiffer spring boyoyoings faster

The experiment brought me here…and the haircut at time stamp 6:15 that happened in under 7 seconds blew me away. Great video and smooth editing for sure!

"Watch gravy pull two meatballs together". I'm being totally honest, that was what I read and now I am a bit dissappointed it wasn't that. Dissappointed and hungry, apparently.

I did this experiment for my 8th grade science fair and had the same issue with sensitivity. I replaced the wire with fishing string, used 2 pound lead weighs on my bar, and 15 pound lead weights on the floor. I used a small paddle hanging from the bar into a dish of water to dampen the noise from air currents. My setup meant I couldn’t use the torsional rigidity of the string, which was now almost zero, but using a time lapse I could measure the position of the bar as the bar swung from ~80 degrees off, to the lead weights touching. Position -> velocity -> acceleration. I think I was quite off, but within 2 orders of magnitude. Basically just confirming gravity’s pull was measurable, but very weak. That was pushing my limit of understanding of physics at the age. I remember being really awed at being able to see gravity behave in a way I’d never seen before

The Cavendish experiment and Millikan's oil drop experiment were the two historical experiments that really struck me when I was studying physics. Being able to see gravity directly, or being able to see the influence of a single electron's charge - it's just mind blowing. I love Von Jolly's version of the thing as well.

I love how this is the easiest way to disprove flat-earthers but none of them have the patience to do the experiment

Flat earthers are gonna say it's fake ☠️

“the boi-oi-oing” 😂😂😂 Well said! Efficiently and effectively conveyed what you were talking about. Honestly brilliant. 👏👏👏

I vote for a sister series to Matt's calculating pi by hand series in which you calculate g in more and more elaborate ways

Flat Earthers be like: That is static electricity, not gravity

I helped set this experiment up and I can tell you that Steve has the patience of a saint! He very much downplays just how tricky and finickity this experiment was to set up! I had to leave as I thought I was losing my mind and it reminded me why I am not an experimentalist! Frankly, I am blown away with how well this came out!