Question

Does density vary with temperature?How?

Answer 1

Density changes with temperaturebecause volume changes with temperature. As you heat something up, the volume usually increases because the faster moving molecules are further apart. Since volume is in the denominator, increasing the volume decreases the density.

Answer 2

Yes, This can be explained both with the formula and Conceptual Understanding,

First, I am explaining this with the help of a formula,
We know that PV = NRT (Here P is pressure, V is volume, T is Temperature, R is constant , N is no. of moles )

If we keep everything constant, Except Volume and Temperature , we can get a Relation that ,

Volume is Directly Proportional to Temperature, i.e If temperature is Increased then Volume is Increased,

We also knew that, Density = Mass / Volume,
Density is Inversely Proportional to Volume, i.e If volume Increases then, Density decreases,

So, By all these Statements, We can say that, If temperature increases, Then Volume Increases, and eventually Density Decreases,

So, Temperature is inversely Proportional to Density, 

Now, Here is Conceptual Understanding,

We already learnt in Physics about Thermal Expansion, Cubical Expansion, and Lateral Expansion, 

These all tell that, If there is a increase in temperature in a body or material, Then the Volume of the body or material Increases irrespective of material , i.e Even Iron rod expands in Summer ! , So, Increase in Volume,

So this tells us that, If change in Temperature is Positive , Then Volume Increases, And eventually again, The Density Decreases,

So, If the change in temperature is negative then, The volume decreases and eventually the density Increases,

Therefore , Yes, Density Vary with Temperature, Here is the reason for it,
And also remember that, Density is Inversely Proportional to Temperature,

Hope you understand, Have a Great Day,
Thanking you , Bunti 360 !