a piece of silver cut in half,density stays the same.Why?

2 answers

because the mass and volume lowered. It was not squished to make density increase.

Density= m/v
Density is the mass per unit volume OR
d = m/v.
When you cut a piece of silver in half, the mass decreases by half and the volume decreases by half so the RATIO (m/v) stays exactly the same.