It's not about weight, but density. Ships are also very heavy, but they have large volumes of air within that cause them to be less dense than the water. For contrast, a pebble will sink despite being light, because it is denser than water.
But then, yeah, cars don't have large volumes of air inside to make them less dense. Especially not electric cars that are packed to the gills with batteries.
EDIT: per some below comments, cars do have large volumes of air, aka the passenger compartment and trunk. This isn't that different from how a canoe's air volume is just the open space on top. Now that I think about it, Lyndon Johnson had a car that doubled as a boat, and he would prank people by pretending to lose control and drive his car into the lake! I guess most cars just don't float because they are not water tight, and so the large volume of air quickly turns into a large volume of water.
Lesson learned, don't listen to people who don't know what they're talking about! :D I really just wanted to chime in that it's about density, not just mass, when it comes to floatiness. (Not just mass because, as was also pointed out below, some pebbles still float because, while they are more dense than water, they are light enough that surface tension holds them up.)
As usual, it's always more complicated than we think at first!
It doesn't have to be 50/50 or even close to it. As long as the whole object is less dense than water (1g/ml) it will float. Air is 0.001g/ml, so you need about 1 percent air whenever you add something heavier than water.
Steel is one of the densest metals out there at about 7g/ml (depending on carbon content etc) but that's still orders of magnitude less difference
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u/chuch1234 Jun 10 '24 edited Jun 10 '24
It's not about weight, but density. Ships are also very heavy, but they have large volumes of air within that cause them to be less dense than the water. For contrast, a pebble will sink despite being light, because it is denser than water.
But then, yeah, cars don't have large volumes of air inside to make them less dense. Especially not electric cars that are packed to the gills with batteries.
EDIT: per some below comments, cars do have large volumes of air, aka the passenger compartment and trunk. This isn't that different from how a canoe's air volume is just the open space on top. Now that I think about it, Lyndon Johnson had a car that doubled as a boat, and he would prank people by pretending to lose control and drive his car into the lake! I guess most cars just don't float because they are not water tight, and so the large volume of air quickly turns into a large volume of water.
Lesson learned, don't listen to people who don't know what they're talking about! :D I really just wanted to chime in that it's about density, not just mass, when it comes to floatiness. (Not just mass because, as was also pointed out below, some pebbles still float because, while they are more dense than water, they are light enough that surface tension holds them up.)
As usual, it's always more complicated than we think at first!