Plastic is any of a wide range of synthetic or semi-synthetic materials that are mouldable. There are two main types of plastics: thermoplastics, which soften when heated and harden when cooled, and can be remoulded, and thermosets, which set into a rigid or non-melting shape after heating and cannot be remoulded. Common plastics include polyethylene, polyvinyl chloride, polystyrene, nylon, and polycarbonate. Plastics are formed into objects using various moulding processes like injection moulding, blow moulding, and rotational moulding. Injection moulding is the most common method and involves melting plastic and