Despite only a single-digit change in weight, the phones are noticeably less weighty. Dr. Drang says there are two reasons behind that. Firstly, even though your brain may perceive an 8 to 9 percent reduction in weight as negligible, the drop is significant enough to create a lighter sensation in your hands.
Apple has used titanium for the iPhone 15 Pro‘s frame instead of stainless steel, so the weight reduction is not evenly spread, rather it’s concentrated on the sides. That’s why the moment of inertia has reduced more than it would have if the weight decrease were distributed uniformly.
The moment of inertia has reduced by 14 to 15 percent on the longer side, making it easier to turn the iPhone 15 Pro. This gives you the impression that the phone is a lot lighter than the iPhone 14 Pro than it actually is.
In short, the shift from stainless steel to titanium has reduced mass at the perimeter, reducing the ‘moment of inertia more than a uniform reduction in mass would have.’ This makes it easier to handle the iPhone 15 Pro.
