Frist theory: Ice,once it hits the right temp, can turn black , this "dark" ice is very dangerous, the ice will probally not be water, but more of a gas.
This weeks topic is......."A sword or some other item of your choice block a bullet form a gun of your choice and or some other projectile"
It can indeed split a bullet; however, you would need to be incredibly lucky, have insane forearm strength to hold the sword while it is happening, and an incredibly sharp blade in order to split it.
Mostly it will probably just smash into the blade and push it back into you because your edge isn't sharp enough.
Blocking isn't exactly a complex topic, you put a stationary object in front of a moving object, and the stationary object absorbs the momentum of the moving object, resulting in two stationary objects, with respect to each other.
The simplest possible demonstration is a moving object that is not connected to any other objects (like a bullet), and a stationary object connected to the Earth. Anything moving at the speed of the Earth will be considered to have 0 momentum.
One of four things will result
1. The joint between the stationary object and the Earth will break, resulting in two moving objects both moving at a slower velocity than the original moving object.
2. The momentum of the moving object will be absorbed by the stationary object and the Earth, and all objects will have 0 momentum.
3. The moving object will break through the stationary object.
4. The moving object will rebound off the stationary object.
So yes, if you take a sword made of a harder metal than the bullet, and of sufficient thickness, and lodge it deeply in the ground, then somehow shoot it with a bullet, the sword will block the bullet, and you will probably lose an eye to a ricochet.
Also, since you haven't tested these hypothesis yet, they are NOT theories.