How does variations between no gravity and normal gravity change every day life?

Question

Image a world that superficially appears to have Earth-like gravity. However, the moment you do not in any way touch the ground or something else that is touching the ground, there is no gravity for you. E.g.:

• You jump, you're floating.
• You run (definition= "to go quickly by moving the legs more rapidly than at a walk and in such a manner that for an instant in each step all or both feet are off the ground"), you float.
• You touch a wall or somebody standing/sitting/whatever and then jump, it will be like a jump on Earth.

This is true for everything (animals, stones, houses, water, etc.) except atmosphere (or no one would be able to breathe).

To go back to the ground, you'll have to touch something that is already touching the ground. (And depending on what hight your are, you could easily crash.)

I imagine that transportation could get easier. But behaviour like throwing would not be recommended.

How does this change every day life? (Imagine a 21st century development)
Would keeping the momentum make life more complicated? (E.g. when jumping up, you would keep your momentum - like in vacuum? - and float up)

Edit
I was thinking about movement in space with my question about the momentum: E.g. thrusters of an Earth space probe fire in direction A, they move the space probe in opposite direction B with low friction. Thus, a person jumping is like a space probe whose thrusters fired.

Answer 1

I am assuming one additional rule: dust or very small particles would be affected by the gravity just like the air. This will avoid the particularly grim scenario that Mołot offers.

I would assume this world would have creatures that fly around. And there is no reason to not have one. You don't even need to be light to fly. Also the wings would be different, they would be more like fins. Probably most life will never touch to the ground. In fact touching the ground will be like having a curse: the curse of gravity. Something that you would use to scare the children.

Answer 2

Keeping momentum won't work

Either your world is frictionless, and that's really hard to imagine and simply couldn't work anyway near our world does, or you break energy conservation. If the latter, rock floating in atmosphere (think close orbit) would constantly produce friction heat. It will make atmosphere hotter and hotter, without real limit. Oceans would boil out, atmosphere would turn to plasma etc.

No gravity without touching

So back to the main question. World like this could not develop. Sand raised by wind would never drop back to the ground. Raindrops wouldn't fall. Rocks and splinter created by lightning hitting ground? In the air. Forever. Volcanic ash? Same here.

You would have a LOT of abrasives up in the air. Erosion on unimaginable scale. Your world would be pretty flat, and air would be unsuitable for breathing, unless your creatures would have really, really good air filters. Or (as I believe) life would stay at single-cell level or only slightly higher. Or underwater, where things are pretty normal.