Why does your blood turn red right when it hits the surface of your skin?
Because your inside blood is purple and it doesnt have enough air for it to be red so when it comes out the blood just gets air real fast and it turns red real fast.
What kind of wound occurs when skin scrapes against a hard surface and tiny blood vessel break the outer layer of skin?
Blood vessels supplying the capillaries at the surface of your skin dilate (widen) so more blood reaches the surface of your skin and more heat is lost by radiation. This is why you look red (flushed). Sweat glands in your skin release more sweat, this forms a layer on the surface of the skin which cools the body as it evaporates.
What kind of wound occurs when the skin scrapes against a hard surface and tiny blood vessels break into the outer layer of the skin?
This is a process known as vasodilation, which takes place if your core body temperature gets too high. The capillaries just below the epidermis dilate to allow more blood to reach the surface of the skin. The blood carries with it thermal energy, which is then lost by radiation upon reaching the surface.