/sci/ - Science & Math

>Why is the sky black?
because it's night
>How do you know if the surface of Earth is convex or concave?
pee on the ground

not OP, but pic related

>>11313461
>How do you know if the surface of Earth is convex or concave?
Go to the beach and watch some ships coming in close to shore. You will see the top first. Since you can see the top before the bottom, that means there is a convex surface in between you and the ship (the ocean). If the ocean was concave, you'd be able to see the ship from a top view from a distance, and gradually see less of it as it got closer until it was a side view.

>>11313533

>>11313533
>this bullshit again

>>11313461
>Why is the sky black?
Because most of it is empty space, so there's not much to see.

>How do you know if the surface of Earth is convex or concave?
There's many reasons as to why, but here's a simple reason to how we know. See picture.

>>11313737
And this.

>>11313499
now put the light very far away

>>11313740
And this.