Difference between the material properties: Hardness, Toughness and Strength.

These three are the major mechanical properties of a material. For a layman these three might be same but for a Mechanical Engineer they are different.

Hardness is the property of a material to resist indentation and scratching. While toughness refers to the resistance to failure. It is the property to withstand strain without tearing. Strength of a material means the maximum load which the material can withstand.