Tutor profile: Harold J.
Subject: Earth Science
Why are the deepest parts of the ocean actually fairly close to land?
The deepest parts of the ocean are so close to land due to a phenomenon called subduction. The Earth's crust is divided up into segment called plates. These plates move around on the Mantle in a process known as plate tectonics. With these plates moving around, they can collide into each other with a whole lot of intensity. When they do collide, you sometimes get oceanic crust colliding with continental crust. When this occurs, oceanic crust is driven underneath the continental crust (because oceanic crust, composed of mostly iron and other heavy elements, is denser than continental crust, which is mostly silicon, is comparably less dense). The place where the oceanic crust "subducts" under the continental crust is where very deep oceanic trenches form.
Why does water expand when it freezes?
Water is a polar molecule, meaning that the shared electrons between the two hydrogen ions and one oxygen ion are unevenly distributed around the oxygen ion. Because of this uneven distribution, water can form very strong "hydrogen bonds" between more positive hydrogen ions and more negative oxygen ions of different water molecules. Due to the shape of a water molecule, water will expand when it becomes cold enough for molecular motion to slow and hydrogen bonds to become very strong (i.e. when water freezes).
A person is holding two baseballs, one in each hand. From the same height, the individual drops one straight down and throws the other horizontally. Which ball will hit the ground first? Neglect air resistance.
Both balls will actually hit the ground at the same time. Both balls are in free fall, meaning that the only force acting upon each ball is gravity. Since gravity affects only vertical velocity and not horizontal velocity, both balls will fall at the same rate and hit the ground at the same time.
needs and Harold will reply soon.