What is the difference between "Strong" and "Stiff"?

[kenny1999]

Sometimes I see people saying that a material is strong and stiff and ...

What is the difference between strong and stiff in the chemistry sense?

Could it be strong but not stiff or stiff but not strong?

 

[etotheipi]

I'll let someone else give a more formal/chemical assessment, however the stiffness of a material relates to how much deformation occurs given an applied stress, whilst strength refers to the value of stress at certain reference points: i.e. ultimate tensile strength being the stress at which failure occurs, yield strength being the stress above which permanent deformation occurs, etc.

The Young's modulus of a material is a measure of stiffness, specifically it is a ratio of stress against strain.

Could it be strong but not stiff or stiff but not strong?

Yes, I believe so.

 

[DaveC426913]

Could it be strong but not stiff or stiff but not strong?

Concrete has incredibly high compressive strength, but it is relatively easy to torque off a chunk.

You could stand on concrete just a couple of inches thick, but that same thickness, if you picked it up, would easily crumble in your hands.

(Actually, I don't think that's what constitutes "stiffness").

 

[PeroK]

When I saw the title of the thread I thought it would be about alcohol. As in a strong drink against a stiff drink.

 

[BillTre]

As in a strong drink against a stiff drink.

strong: straight liquor
stiff drink: a smoothie (more resistant to flow)

 

[Borek]

I am afraid it is apples and oranges.

 

[DaveC426913]

I am afraid it is apples and oranges.

Welllll, a screwdriver can be made both strong and stiff, but an Appletini is neither.