The Elastic Modulus is a measure of a material's ability to deform under stress and return to its original shape when the stress is removed. It quantifies how stiff or flexible a material is. For example, materials like rubber have a low elastic modulus, meaning they can stretch easily, while metals like steel have a high elastic modulus, indicating they are much stiffer and resist deformation. This property is crucial in engineering and construction, as it helps determine how materials will behave under various loads. Understanding the elastic modulus of materials like concrete or wood ensures that structures can withstand forces without failing, making it essential for safe design practices.