Decreases, when you move upward and increases moving in due to various forces like gravity
Explanation:
The speed of seismic waves is affected by the density of the underlying rock.
Seismic waves are elastic waves that transmits elastic energy from one point to the other.
These waves generally produced during an earthquake.
- The higher the density of rock bodies, the faster the wave travels.
- Rocks that are well packed with little to no void have a higher seismic velocity.
- Where density of rock is low, the speed is also low
Answer: Chemical change
Explanation:
Physical change is a change in which there is no rearrangement of atoms and thus no new substance is formed. There is only change in physical state of the substance. The change can be reversed using physical methods.
Chemical change is a change in which there is rearrangement of atoms and thus new substance is formed. There may or may not be a change in physical state. The change can only be reversed using chemical methods.
Thus when iron and sulfur are heated in a test tube, the chemical change occurs and thus lead to formation of new substances which could not be separated using magnet.
