While taking a journey through the center of the Earth you will experience many different things. You will encounter different layers, differences in chemical composition, and there will be unusual properties.
While traveling you will go through four different layers: the crust, mantle, outer core, and the inner core. These four layers all have distinct qualities that make them up. The chemicals that make them up and the physical properties they have are both things that make each layer the way it is.
The chemical compositions of the layers are unique. The less dense compounds make up the core and mantle, the denser compounds make up the inner and outer core. The crust is made up of mostly oxygen, silicon, and aluminum. After you go through the crust you go to the mantle which is made up magnesium, but less aluminum and silicon than the crust. The outer core is believed to be mostly iron and nickel. The inner core is a solid ball of iron and nickel. Those are the different chemicals throughout the Earth during a trip to the center of the Earth.
The four layers also consist of different physical properties you would travel through. The first layer, crust, is about 10 miles of rock and loose materials. Underneath the continents, the crust can be three times thicker than as it is under oceans. The next thing you encounter is the mantle. It is approximately 1,800 miles deep and is made of a thick solid rocky substance that is 85% of the Earth's total mass. Next, is the outer crust which reaches 3,000 miles beneath the surface. It is made up of super-heated molten lava. The inner crust is another 900 miles deeper into the Earth and is solid iron and nickel.
These are the changes you would see if you were to got o the center of the Earth. The layers, chemical compositions, and the physical properties are all important to how the Earth is made.