To make a good product, choosing materials with the right properties is essential. A mobile phone, for example, should withstand high stress, be hard but not crack, and also be comfortable to hold. In this film, we will take a closer look at material properties. Elasticity and plasticity describe how materials behave under stress, while yield strength and tensile strength indicate a material's durability. Hardness measures resistance to damage, and thermal expansion describes how materials expand with temperature changes. By understanding these properties, we can create products that are both effective and durable.