 Sulfur is the 16th element of the periodic table and is a non-metal. In its elemental form it is a bright yellow crystalline solid at room temperature. In this video we are going to look at the basic physical and chemical properties of sulfur. We will also discover some real life applications of sulfur-containing compounds including how it is found in fuels and what happens when it is combusted and consequently reacts with oxygen. The most common allotrope of sulfur is octosulfur, where eight sulfur atoms join together to form this ring structure and its very prevalent nature. It is commonly found around volcanoes. Yellow elemental sulfur burns with a blue flame and melts into a deep red liquid. Its many compounds can be found in everyday life. Does cutting onions reduce you to tears? The sulfur-containing compound responsible for this is a known substance that makes your eyes produce tears. Stinky feet and bad breath blame those on sulfur-containing compounds too. Overcooked those boiled eggs? That blue-gray lining around the yolk is due to the reaction of the iron in the yolk and hydrogen sulfide created in the whites, forming iron sulfide. Ever smelled a natural gas leak? That is actually the smell of a spiking agent, which is a class of sulfur-containing compound called thiols or mercaptans, such as methane thiol. Methane is the gas. The thiol is the sulfur-smelling part. The sulfur smell is strong enough so that you can detect a potentially dangerous leak. In fact, fuel for cars and other vehicles also contain these sulfur compounds. The combustion of these fuels also means the combustion of these sulfur-containing compounds. This results in the production of sulfur dioxide, which reacts with the oxygen in the air, to create sulfur trioxide. Sulfur trioxide then reacts with water vapor in the atmosphere to produce sulfuric acid. Sulfuric acid then dissociates into its respective ions, meaning there is a higher concentration of hydrogen in our rainwater, and so the pH is lower. This means that it is acidic. Bicycle and car tyres would not exist without sulfur. White latex is tapped from rubber trees. In this natural state, it is not very useful, so it is vulcanized or cooked with sulfur to make it harder, stronger, and longer lasting. In its natural state, the rubber molecules are long chains that are tangled up and only weakly linked. When it is vulcanized, the sulfur helps form extra bonds, which are known as crosslinks. This makes it harder. Did you know that curly hair has a connection to sulfur? Keratin, the main protein component of hair, also has lots of disulfide bridges. The more bridges present, the curlier your hair. In fact, straightening curly hair involves breaking these bridges, either using heat or chemicals. Do you love the smell of the seaside? That distinct smell is actually from sulfur-containing compounds released by algae and decomposing seaweed, which is very toxic, but present in low enough concentrations so that it is safe for you to enjoy your time at the beach. And finally, and maybe most importantly, sulfur is an essential element to life. It is present in one of the 22 amino acids that make up proteins. So when living things die and get buried underground to form fossil fuels, the sulfur remains there, only to be released as an OSO when the fuels are burnt, again leading us back to acid rain. So there you have it, sulfur, not as dull as you might have imagined. Just remember volcanoes, onions, smelly feet and eggs, gas, fuel, acid rain, curly hair, the seaside, and amino acids.