Kitchen utensil the turn of the 20th century, Maria Parloa noted that kitchen utensils were made of (tinned or enamelled) iron and steel, copper, nickel, silver, tin, clay, earthenware, and aluminium. The latter, aluminium, became a popular material for kitchen utensils in the 20th century. Copper has good thermal conductivity and copper utensils are both durable and attractive in appearance. However, they are also comparatively heavier than utensils made of other materials, require scrupulous cleaning to remove poisonous tarnish compounds, and are not suitable for acidic foods. Copper pots are lined with tin to prevent discoloration or altering the taste of food.
Foil (fluid mechanics) Foil (fluid mechanics) A foil is a solid object with a shape such that when placed in a moving fluid at a suitable angle of attack the lift (force generated perpendicular to the fluid flow) is substantially larger than the drag (force generated parallel to the fluid flow). If the fluid is a gas, the foil is called an airfoil or aerofoil, and if the fluid is water the foil is called a hydrofoil. A foil generates lift primarily as a result of its shape and angle of attack. When oriented at a suitable angle, the foil deflects the oncoming