Q. Tinfoil has a shiny side and a dull side. Why is this? My co-worker says you should put the shiny side down when covering something in the oven. This doesn't seem plausible to me. What are the facts?
A. First, a brief bit of history.
In the 19th century, Thomas Edison invented a phonograph machine, in which a sound-driven vibrating needle impressed grooves into a cylinder covered with a thin foil of the soft metal, tin. In the 20th century, tinfoil was being widely used as a wrapping material for foods and drugs. By the middle of the century, tinfoil had been replaced almost completely by thin foils of a different metal called aluminum. Yet many people persist in calling aluminum foil "tinfoil." We chemists get annoyed at things like that. Get with it, folks! This is the 21st century!
Now, about aluminum foil. Aluminum foil is made by rolling sheets of 98.5 percent pure aluminum metal between pairs of polished, lubricated steel rollers. Successive passes through the rollers squeeze the foil thinner.
Household aluminum foil is so thin (0.0005 of an inch) that the rollers can't handle it without tearing it. The final rolling is therefore done on a sandwich of two sheets, face to face. The outer surfaces emerge with a finish as smooth as the rollers, while the two face-to-face inner surfaces emerge with a matte finish. Hence, a shiny side and a duller side. When you use the foil, it makes no difference which side is up, down or sideways.
Q. I bought some Reynolds Wrap Release, a nonstick aluminum foil. It works great as an oven pan lining. Even dripping pizza cheese won't stick to it. What is the nonstick coating? Is it Teflon? Can it be used safely at high temperatures?
A. Reynolds (and its parent company, Alcoa) brought Release to the market in 2002. They will not say what the coating is, except that it is "effective as a nonstick surface and safe for food contact." Reynolds says it is safe at any temperature, including for grilling, and doesn't contain Teflon.
Q. I have heard that cooking in aluminum pots and pans can be dangerous. But what if they're made of hard-anodized aluminum?
A. Aluminum is the most abundant metal in the Earth's crust. Widely distributed in soil, plants and water, including our food and drinking water, it is impossible to avoid. According to Health Canada, that nation's public health agency, about 95 percent of an adult's daily intake of aluminum comes from food. And less than 1 percent of all ingested aluminum is absorbed by our bodies.
The suspicion of a relationship between aluminum and (take your choice) Alzheimer's, Lou Gehrig's or Parkinson's disease has been floating around for about 20 years. The brains of some Alzheimer's patients have been found to contain abnormally high concentrations of aluminum, but nobody knows whether that is a cause of the disease or a result of it.
Because Alzheimer's is a chronic disease that develops over a long time, the long-term ingestion of aluminum in drinking water, which is relatively easy to monitor, should be a logical way to search for a correlation. And yet, epidemiological attempts to link aluminum in drinking water with Alzheimer's disease have been either inconclusive or contradictory.
There is little doubt that whatever aluminum leaks into our foods from cookware is a small fraction of the aluminum we ingest through normal eating, drinking and breathing on our aluminum-pervaded planet.
As for hard-anodized aluminum, the surface has been subjected to a process that builds up its natural coating of oxide. Aluminum oxide is a very hard, nonreactive substance that forms an impenetrable coating. So the food never actually touches aluminum metal.
Q. I'm shopping for stainless steel cookware. Some brands brag that they're made of 18/10 stainless steel, while others say they're 18/8. What's the difference?
A. The numbers are the percentages of chromium and nickel, respectively, in the alloy, so the 18/10 contains 2 percentage points more nickel than the 18/8. More nickel gives the steel a brighter surface and greater corrosion resistance, but the difference is very small. Both are top-quality stainless steels. If the type of steel isn't specified, it might be 18/0, a lower quality containing no nickel at all. The surfaces will be comparatively dull.
FAQs
Most metals are good conductors of heat and electricity. Many metals are heavy or dense, although some metals, such as lithium, are light enough to float on water! Most metals are hard. Most metals are malleable or may be beaten into a thin sheet.
What should I know about metals? ›
Metals form positively charged ions called cations through loss of electrons. They react with most other elements, but especially nonmetals, such as oxygen and nitrogen. The most commonly used metals are iron, aluminum, copper, zinc, and lead. Metals are used for an enormous number of products and purposes.
What are the 7 properties of metals? ›
Physical properties
- high melting points.
- good conductors of electricity.
- good conductors of heat.
- high density.
- malleable.
- ductile.
Although there are various kinds of metals and metal alloys, most can fit into one of five basic categories. The top five fundamental categories arguably include ferrous, nonferrous, precious, base, and noble metals.
What is the most important metal? ›
Iron. Iron is the most useful metal of all. It is strong, abundant, and easy to work with, especially when refined into various types of steel.
What are 3 interesting facts about metals? ›
The word metal comes from the Ancient Greek word 'metallon' which means quarry or to mine or excavate. The most abundant metal in the universe is iron, followed by magnesium. The tallest free-standing structures in the world are made of metals, primarily the alloy steel.
What are 10 things made from metal? ›
Some of the objects made from metal are : Jewellery Wires Utensils Foil paper Statues Gates Nails
- Jewellery.
- Wires.
- Utensils.
- Foil paper.
- Statues.
- Gates.
- Nails.
Common Methods Used To Identify Metals
- Eye Test. Sometimes you really don't need more than what you carry with you every day. ...
- Hardness Test. A hardness test is most useful for indicating the presence of lead, a relatively soft metal and notorious neurotoxin. ...
- Spark Test. ...
- Magnet Test.
- Iron or steel is used to construct the house and bridges.
- Aluminium wires are used.
- the liquid metal mercury is used in making a thermometer.
- Zinc is used to protect the iron from rusting.
- Gold and silver are used for making jewellery.
Chemically, gold is a transition metal and a group 11 element. It is one of the least reactive chemical elements and is solid under standard conditions. Gold often occurs in free elemental (native state), as nuggets or grains, in rocks, veins, and alluvial deposits.
What Are Metals Made up of? Metals are made up of atomic materials such as electrons, neutrons, and protons. Atoms of different elements can be distinguished from one another by the number of protons they contain. Metals comprise about 25% of the earth's crust.
What are the 20 properties of metals? ›
Properties of Metals
- Metals can be hammered into thin sheets. It means they possess the property of malleability.
- Metals are ductile. ...
- Metals are a good conductor of heat and electricity.
- Metals are lustrous which means they have a shiny appearance.
- Metals have high tensile strength. ...
- Metals are sonorous. ...
- Metals are hard.
Diamond is not a metal in anyway its just an allotrope of carbon. It does not show any physical properties or chemical properties of metals like electrical conductivity, malleability, ductility, reaction with acids or salts etc.
What is the least precious metal? ›
Silver: The least costly of the precious-metal group, silver is also very malleable, ductile, and corrosion resistant. Because it is not attacked by alkaline solutions, it is used to contain caustic soda and potash in all concentrations.
Which metal is used in daily life? ›
Nickel, cobalt, and chromium are often found in everyday consumer objects, such as jewelry, clothing, leather, technological devices, household items, and other daily-use objects [1]. Gold, palladium, mercury, copper, aluminum, titanium, iron, platinum, tin, zinc are also occasionally found in these items.
What is hardest metal on earth? ›
- While there are several parameters for categorizing metals in terms of hardness, chromium (687-6500 MPa) is the hardest known metal on the planet.
- It should not be confused with Tungsten, which has the highest tensile strength of any metal.
- Tungsten in its pure form is typically brittle and can shatter on impact.
Tungsten
2 to 3 times harder than titanium and cobalt, tungsten won't bend and keeps its finish forever.
What is the number 1 strongest metal? ›
Who invented metals? ›
Ancient man first found and began using Native Metals approximately 5000 years BC. Over the next 2000 years, leading up to the Bronze age, man mastered how to find, manipulate and use these native metals in better ways and in a range of applications.
Why is metal important in life? ›
Metals are usually ductile, malleable, shiny, and can form alloys with other metals. Metals are tremendously important to a high energy society: they transport electricity in the electrical grid, and provide many services. Various manufacturing processes around the world uses more than 3 gigatonnes of metal every year.
Today's coins are made from metals such as nickel, copper, and zinc. Instead of using one metal to make a coin, multiple kinds of metal are pressed together into layers. This is called a “clad” coin. The layers of a clad coin are like a sandwich.
What causes metal to rust? ›
Metal corrosion, also known as oxidation, occurs when an ionic chemical reaction meets the presence of oxygen on a metal's surface. The oxidation process takes place in the air while metal is simultaneously exposed to water or to acids.
Is steel a metal? ›
As steel is an alloy, it is not a pure element and is, as a direct result, not actually a metal. Instead, it is actually a variant of a metal. Although steel is composed of iron – which is a metal – the non-metal carbon within its chemical make-up means that it is not a pure metal, so it cannot be classed as one.
What metal is not magnetic? ›
Many common metals such as aluminum, copper, brass, gold, silver, titanium, tungsten, and lead are not ferromagnetic. They cannot be made into magnets and will not be attracted to magnetic fields.
Can all metals rust? ›
Only iron can rust. That means other metals that do not contain iron are not susceptible to rusting. This makes them ideal for outdoor placement, as they'll last much longer in natural conditions.
Are all metals magnetic? ›
Not all metals are magnetic. Actually, it depends on what you mean by the word "magnetic". There are four basic types of magnetism that a material can have: superconducting, diamagnetic, paramagnetic, and lastly ferromagnetic. Superconducting materials are strongly repelled from permanent magnets.
How was metal first made? ›
People first began making things from metal over 9000 years ago, when they discovered how to get copper from its ore. They then learned how to make a harder alloy, bronze, by adding tin to the copper. About 3000 years ago, they discovered iron.
How many metals are there? ›
There are about 70 metals out of 92 natural elements in the periodic table.
How is metal formed? ›
The Origins of Metal
All of Earth's metals originated billions of years ago when the universe first appeared. Inside the ultra-hot environment of the stars, simple hydrogen and helium atoms fused to create heavier elements.
Is gold toxic to skin? ›
Many human problems arise through the ability of metallic gold to induce allergic contact hypersensitivity. While gold in jewelry can evoke allergic reactions, other metals such as nickel, chromium and copper present in white gold or alloys exhibit more serious clinical problems.
Pure gold is a noble precious metal, and the least reactive of all metals. Gold does not rust, nor will it tarnish.
What metal will replace gold? ›
"Oxidation-resistant Cu (copper) could potentially replace gold in semiconductor devices, which would help bring down their costs. Oxidation-resistant Cu could also reduce electrical consumption, as well as increase the lifespan of devices with nanocircuitry," according to the professor in a statement.
Will we run out of metal? ›
The Earth's crust is approximately 21 miles deep, and even that is less than 1% of the planet's overall volume. It is safe to assume then that we will never exhaust the Earth's metal resources in their entirety.
What is gold made of? ›
100% of gold found naturally is isotope Au-197. 28 other isotopes can be produced artificially and are all radioactive. Gold along with silver and copper, form a column in the periodic table. They are found naturally and were the first three elements known to man.
Where do metals occur? ›
The vast majority of metals are found in ores (mineral-bearing substances), but a few such as copper, gold, platinum, and silver frequently occur in the free state because they do not readily react with other elements.
Are all metals shiny? ›
All metals have a shiny appearance (at least when freshly polished); are good conductors of heat and electricity; form alloys with other metals; and have at least one basic oxide.
What 4 features define a metal? ›
Metals are elements that lose electrons easily, that are lustrous (reflective), malleable (can be molded into other shapes), and are good conductors of heat and electricity.
What is the nature of metal? ›
Metal oxides are basic nature. Some are amphoteric.
Is glass a metal? ›
Glass is made of silicon dioxide or quartz. Therefore, it is not at all a metal, it is an amorphous non-metal.
Is coal a metal? ›
Coal is a non-metal.
Yes, black diamonds are real and natural diamonds. They come naturally from the earth with the same chemical composition as traditional colorless diamonds. The main difference between white and black diamonds are the number of inclusion and spots, which are responsible for giving black diamond their color.
What metal is the most unbreakable? ›
Tungsten. Tungsten is an impressive mineral. As a pure metal that is not mixed with other metals to increase hardness, it has the highest tensile strength of any metal. Tensile strength refers to how much force the metal can handle before it begins to change shape or give in to the pressure.
What is the heaviest metal? ›
Osmium is the most dense metal! Many people are familiar with lead (11.3 kg/L), but osmium is twice as dense (22.6 kg/L)! Each liter (about 1/4 gallon) of osmium weighs 22.6 kg (50 lbs). For comparison, each liter of water weighs only 1 kg (~2.2 lbs).
What is the prettiest metal? ›
Vanadium may be the most beautiful metal of all – once extracted and dissolved in water, various forms of vanadium turn into bright, bold colors.
What is a common metal? ›
Aluminum, cadmium, chromium, copper, iron, lead, nickel, tin, zinc, or any combination of these elements are considered common metals.
What is the most common metal in human society? ›
1. Iron. Accounting for around 5% of the Earth's crust and the 6th most common element in the universe, iron is a highly abundant and one of the most frequently used metals. In the modern periodical table of elements, iron is denoted by the symbol Fe and has an atomic number 26.
What are 5 things made of metal? ›
Some of the objects made from metal are : Jewellery Wires Utensils Foil paper Statues Gates Nails
- Jewellery.
- Wires.
- Utensils.
- Foil paper.
- Statues.
- Gates.
- Nails.
- Iron or steel is used to construct the house and bridges.
- Aluminium wires are used.
- the liquid metal mercury is used in making a thermometer.
- Zinc is used to protect the iron from rusting.
- Gold and silver are used for making jewellery.
Uses of metals:
- Jewellery and ornaments are made of gold, platinum, and silver.
- Construction materials include iron and steel.
- Utensils made of aluminium and steel are used.
- In thermometers, mercury is used to verify the temperature.
- Insulation wires are made of aluminium.
The first step in metal alloy manufacturing is extracting the raw ore from the ground. The ore is then processed to remove non-metal material, such as rock and debris. Metal alloys are then created by melting different metal substances and mixing them.
In modern society iron is the most important of all metals, as it is used to craft different types of steel which is used in a diverse array of applications. Steel is used to make paperclips, skyscrapers, and everything in between. Iron is also an important element in plant and animal life.
Where do metals come from? ›
Most pure metals come from the earth's crust. They are found in ores, which is a solid material that minerals and metals can be taken from. Nearly a third of the planet's mass is the element iron and most of that can be found in the planet's core.
What are 10 common metals? ›
Aluminum, cadmium, chromium, copper, iron, lead, nickel, tin, zinc, or any combination of these elements are considered common metals.
