Podcasts

If someone is brave enough to bite into a lemon, then you can instantly tell from their expression that it wasn't exactly a pleasant experience. There's a reason why we can perceive the taste of sour. If something is too acidic, then it sends a signal to the brain.

Just like animals and human beings, plants can get sick. In many cases, the cause is a fungus. Not a mushroom like you see poking up out of the ground in the woods, but a network of branching, filamentary cells that botanists call hyphae.

If you glance at yourself in a looking glass and notice that you are beginning to look a little dull around the edges - or have maybe even developed black spots - there is a scientific reason for the phenomenon. A mirror can be robbed of its reflective power by the chemical reaction known as oxidation.

Frozen water can be lots of fun. For example, if you have a pair of skates, you can perform elegant moves on the surface of solid-phase H2O. Or you can roll together the fluffy ice crystals that fall from the sky into a snowman. But drivers like it less. They much prefer water in its liquid phase. An internal combustion motor contains coolant - the liquid that carries excess warmth away from the engine when it's burning fuel. And if the coolant freezes when the temperature drops below zero degrees Celsius, then you have a serious problem.

There have been plenty of attempts all over the world to influence the weather with chemical tricks. In Thailand, for example, what is called the 'fon luang', or 'king's rain', is aimed at preventing drought, while what are known as 'hail planes' regularly take to the skies in Germany to subdue potential hailstorms.

In the history of our attempts to master chemistry, explorations of fire are certainly among the most ancient experiments ever performed. And although we have controlled it for thousands of years, the magic of fire remains spellbinding. Take sparklers, for example. There’s little in life quite as satisfying as watching one of these gray rods spark and sputter to life when you light it.

Beer has a long history. Experts say humanity has known the alcoholic beverage for more than 5,000 years. When you think about it that adds up to a lot of hangovers, which is why it's a good thing that modern breweries have also figured out how to make beer that doesn't contain alcohol. There are basically two ways to brew low-alcohol beer. Either you lower the percentage of alcohol in the beverage during the brewing process, or afterwards.

Hard water - sounds like white and flaky showerheads, encrusted water cookers, or stopped-up pipes. Although the clear water that comes jetting out of the faucet might look soft and innocent, it contains substances that can turn pretty hard. Just let a little water from your sink evaporate in a glass. It leaves a thin, chalky white film behind that chemists call calcium carbonate and is commonly known as lime.

Sugar and sweetener - both taste sweet, which is just another way of saying that both interact with the 'sweetness' taste receptors on your tongue. But that's about all they have in common. Otherwise, sugar and sweetener don’t chemically resemble each other in the least. In fact, they belong to completely different classes of substances.

When the first non-stick cookware arrived on the market back in the mid-1950s, it was an instant hit. The images of fried eggs or pancakes sliding straight out of the pan onto the plate proved irresistible to consumers. As with so many other products, however, the discovery that made it all possible involved a series of lucky coincidences.

The key to understanding lies in the molecular structure of hair. A single hair is made up of a bundle of fibers. The individual fibers are in turn made up of even smaller threadlike components known as fibrils. And in their turn, fibrils are made up of chains of protein molecules - mostly the tough structural protein keratin - that are twisted together and attached to one another with chemical bridges made of sulfur or hydrogen atoms. If you want to change it, then you first have to dissolve the bonds.

Your chewing apparatus has to be pretty stable to be able to cope with all the sustenance we shove into it every day. The outermost layer of a tooth, the enamel, is actually the hardest substance that the human body produces. It consists of a mineral called hydroxylapatite.

It’s strange, isn’t it? In both cases you’re dropping something you want to eat into a pot of boiling water, but what happens to the spud is the exact opposite of what happens to the egg. The secret involves the chemical make-up of the potato. It consists largely of starch. It’s a different story entirely with eggs. They’re composed mostly of proteins.

Alcohols are a group of diverse organic compounds, among them ethanol, methanol, propanol and butanol. All alcoholic beverages sold legally must be clearly marked with the percentage of alcohol the drink contains. That number is a measure of how strong the beverage is.

Carbon dioxide is a naturally-occurring chemical compound containing carbon and oxygen which makes up a minute but significant portion of the earth’s atmosphere. It is created when you burn substances that contain carbon - for example, fossil fuels or coal - but is also an end product of respiration in animals. When you breathe, carbon in your body reacts with oxygen from the air, combining to form carbon dioxide.

All organisms – plants, animals, human beings – need carbon to survive. In the air, the element can be found in the commonly occurring compound carbon dioxide (CO₂ ). Plants absorb CO₂ and turn it into carbohydrates. We in turn absorb these carbohydrates when we eat the plants. And when we breathe out, we then release carbon dioxide back into the air. All of these steps together make up the ‘carbon cycle’. The moment an organism dies, this cycle is broken. And even thousands of years later, that moment can be dated using the radiocarbon dating method.

Lots of products out there capitalize on the antibacterial effects of silver. Everything from cleaning cloths and insoles to washing powder and bandages – they all seem to employ the element in some way. Unfortunately, silver can’t really perform miracles. But it can be used quite effectively to control bacteria.

In the old days, sponges only came from the sea. For millennia, brave divers risked life and limb to bring them back to the surface. In the age of plastic, however, you don’t have to expose yourself to danger to acquire one. As a matter of fact, most modern artificial sponges improve on the design from nature in several ways.

If you don’t keep shaking a container of unhomogenized milk, then the thicker, fatty portions of it separate and float to the top. This is liquid cream, which can be ladled off and beaten to produce a stiff foam - whipped cream. Cream is mostly made up of lipids, water and milk proteins.

It doesn’t take long after you’ve polished off a plateful of the delicious vegetable before you are forcefully reminded of it in the restroom. Some people are surprised by the strange odor rising from the bowl after urinating. The unmistakable olfactory experience is caused by organic sulfur-containing compounds.

The whole point of the skin of a cherry is to keep that from bursting. The smooth, slippery envelope protects the fruit from falling prey to funguses or microbes, and water usually just slides right off of one. But the rainstorms feared by fruit-growers are a different matter.

The very first thing many people do when they stumble out of bed in the morning is pour themselves a cup of coffee. The substance in the hot brew that helps wake you up is well-known all over the world: caffeine. Caffeine doesn't only come from coffee beans. Most of the caffeine is synthetically manufactured by the chemical industry.

As far back as the Middle Ages in Europe, blue has always been a color worn by the nobility. Some kings wore blue cloaks to their crowning ceremonies. The dye was made from a substance that had to be brought all the way from far-off India - indigo, which was made from an extract of the indigo plant. In 1897 BASF became the first company to hit the market with a synthetically-produced version of indigo.

Ketchup can be a stubborn condiment. Just when you're ready to bite into a burger, it often refuses to flow. Only when you give the bottle a serious shake or two does it start to move. And there's a reason why. Ketchup isn't your normal, everyday liquid.

All over the world cows, goats, sheep and other mammals are industriously milked every day to provide us with a whole range of dairy products. Children love it, and lots of grown-ups also enjoy a glass of creamy milk every now and again. But you can’t let the milk get too hot. Otherwise it destroys the vitamins, and something forms on top that isn’t tasty in the least - a skin.

The lead of a pencil is made out of the mineral graphite, which is one of the forms - or 'allotropes' - of the element carbon. Diamond is another. It’s also made up of pure elemental carbon. But even though both materials are made of only carbon atoms, they have strikingly different physical properties. Graphite is soft, while diamond is the hardest naturally-occurring mineral. How can one and the same element take on such different forms?

If you stretch a rubber band and then release it, it snaps back into its original shape. As you probably know, rubber has elastic properties, which is why its also called an elastomer. However, the natural state of caoutchouc, or raw rubber, is exactly the opposite of elastic. It’s plastic, which means that it can be shaped and formed like putty.

The discovery of fire opened up whole new worlds of taste for stone-age humans. They could start turning those chunks of raw mammoth meat into beautifully browned roast leg of mammoth and were benefiting from an interesting chemical reaction. In 1912, did French chemist Louis Camille Maillard begin to shed light on the chemical interactions that take place when you roast or grill meat.

Over millions of years of evolution, spiders have developed the perfect material for constructing a net: spider silk. Material researchers can get pretty worked up just talking about its properties. It has five times the tensile strength that a steel thread of the same diameter has, and is at the same time more ductile - stretchable - than most plastic fibers.

When a shirt gets dirty, you usually just have to chuck it in the washing machine, add a little laundry detergent, and let the combination of water and soap do the rest. But some pieces of clothing are too delicate to put in there. As the name implies, dry-cleaning doesn't use any water - or any soap, for that matter.

Every winter it's the same old problem: Ice and snow wreak havoc with traffic. To battle the slick roads, the winter services people are out there day and night spreading salt on the streets.

In simple terms, behind the glass on the front of a plasma screen you’ll find a whole lot of tiny cells that are filled with one of the 'noble' gases, generally neon or xenon. Each of these cells represents a single point - a pixel. If a voltage is applied to the gas, then it converts into what is known as a plasma - and the pixel begins to glow.

If you want your leather shoes to continue to look clean and snazzy, then there's no way around it: you have to polish them occasionally. The polish that you apply contains both fats - lipids - and wax. The lipids make the leather soft and smooth, while the wax protects it from moisture and dirt and gives it a beautiful sheen.

Although the way glow sticks work at first seems almost magical, it's actually pretty simple. They provide a purely chemical source of light. A glow stick is a sealed, see-through plastic pipe containing a fluorescent dye and two different liquids.

After the advent of liquid crystal displays, or LCDs, everybody nowadays has at least heard the term 'liquid crystal'. The high-tech screens are everywhere: in computer monitors, cell phones, digital cameras, and calculators.

Cling film - also called plastic wrap - has to be pretty versatile. It should stretch a lot without tearing, it should keep out the germs, and it has to seal in moisture and aroma to keep those cold cuts from drying out and that chunk of French cheese from smelling up the refrigerator. On top of that, the wrap has to stick to the edge of the plate or the bowl. For many years, one plastic in particular has been performing all of those chores perfectly - polyethylene, or PE for short.

If you put the oil and water together in a single glass, then they act like a couple of suspicious neighbors. Each quickly finds its own level - the oil on top and the water below - and has as little interaction with the other as possible. There's a kind of fence between them that each is unable to overcome on its own: this barrier is called 'surface tension'. But with the help of emulsifiers the oil and water are able to come to terms.

While taking a walk along the beach, you might have noticed shells that have inner surfaces that shimmer in colorful patterns when they reflect the sunlight. The iridescent substance responsible for it is called nacre, or more commonly: mother-of-pearl. The name says it all, because the shell comes from one of the species of mollusk that can also produce pearls.

Hair isn't exactly lying still all the time. It's constantly in motion - we brush it, run our fingers through it, and style it in all kinds of tortuous ways. When we tax it and strain it, the shingles on the outside of a strand of hair can stand up - or even break off. But with the help of conditioner, the hair’s protective outer layer is able to repair itself.

Bioplastics might look artificial, but they sure act like they're organic. When you toss them on a compost heap, for example, they simply disappear. There's no magic involved, though. Compostable bioplastics disintegrate in nature without leaving a trace.

A lot of stuff disappears down the drain that never comes out the other end. If you can’t get to the blockage in the pipe to clean it mechanically, then your only choice to get the water flowing again is a drain cleaner.

In campfire stories, you often hear that someones' hair turns grey or white overnight because of a stressful or frightening experience. That's pretty obviously an exaggeration - but what ARE the factors involved when hair loses its young and vibrant tones and assumes that silvery sheen?

Sugar's ability to adhere to a surface pretty impressive. Back in the 1950s, women even used sugar water to hold extravagant hairdos in place - and it made them pretty indestructible. But how does the sugar do it?

Everyone knows that oil and water just don’t mix. But how come?

A little fabric softener is a big comfort in a tough world. But what chemical trick is behind the feel of clothes freshly-rinsed with fabric softener?

Fat tomatoes, enormous pumpkins, sunflowers that stretch up into the sky - for some home gardeners, what starts out as a hobby turns into a quest for the colossal. There are even competitions. And to have a chance, an ambitious gardener has to do a lot more than just talk to his little green charges. If you want quick growth and sturdy plants, there's just no getting around it – you have to fertilize them.

To protect themselves from the swords and arrows of their enemies, soldiers throughout the ages have used armor made of different types of material: leather, bronze or iron. Nowadays there are more comfortable ways to keep yourself protected.

Few spices are as treasured and avoided! A clove of garlic is both tasty and healthy, but after you eat it, don't be surprised if even your friends start to give you a wide berth. Quite a few people find the smell of garlic disgusting, and will probably keep their distance.

A motor oil's primary function in an engine is to lubricate its moving parts. A thin film of oil keeps the parts from rubbing directly against one another, preventing wear and ensuring smooth motion. To fulfill that function, the oil can’t be too thick or too thin either. But calibrating a motor oil is a lot harder than it sounds.

A leather jacket has been through an astonishing transformation. You can’t even tell that it was once on the back of a cow. How do you make an elegant piece of leather from rough cattlehide?

Nowadays, most of us have a digital camera. In this case you wouldn't even ask such a question. You just print out the pictures. Developing pictures through classic photography is a bit more complicated.

You should be able to chew gum for some time without it dissolving. A determining factor is its chewable base. Nowadays, modern chewing gum consists mainly of a polymer mixture.

Dry ice cannot be found in nature. It is just not cold enough here on earth. In outer space, on the planet Mars for example, carbon dioxide hardens and turns into ice. But who is going to fly to Mars just to get dry ice?

We usually think of a light bulb when thinking of light. Yet, a light bulb has very little in common with a fluorescent tube. In a light bulb, the light is generated by a filament. On the other hand, a gas is stimulated, causing the fluorescent lamp to illuminate.

One can't imagine modern life without glues. They are used everywhere: for wallpaper paste, for handicrafts, for repairs. But why does glue stick? Follow our Chemical Reporter.

Non-iron textiles can make life more convenient. Follow our Chemical Reporter, how fabrics can be tamed and how clothes can become wrinkle-free.