Taste is an incredible but varied thing. In fact, taste changes depending on the habitat of creatures. For example animals who live in rain-forests may not be as sensitive to sucrose or glucose containing compounds as the animals who live in the savanna (because the rain-forest species eats glucose enriched fruit on a daily basis whilst the savanna species doesn’t). This can be true of humans too and it turns out that we are particularly sensitive to “monellin” which is a protein present in the berries of an African shrub. “Monellin” is incredibly more sweet than glucose therefore can be used as an artificial sweetener.
In the book “Molecular Gastronomy” by Herve This, I read that the “Colobus” monkey varies its diet by eating soil and old leaves–> this is not just monkey gone mad but an example of how animals can change their diet to suit their bodily needs. This mud and dry leaves diet contains polyphenol molecules and also “Tannins” which inhibit the digestion of proteins!
Did the “screaming jelly baby” experiment the other day in class- can’t believe there is that much energy inside just one of them!
Like most elements on the periodic table, selenium is an element that no one ever looks at in A level. Of course everyone knows the standard carbon, nitrogen, oxygen, sometimes if we’re lucky we’ll get a chromium or even a krypton!
like everything else on the periodic table, you can work out what an element is like by where it is placed- just as silicon is like carbon (as seen earlier), so selenium is like sulfur as they are both in column 6, so have the same number of electrons in their outer shell and so react in the same way. When we think of sulfur we think of sulfuric acid and the very smelly H2S that makes us gag and shrink inside our lab coats when doing practicals. Selenium also makes Hydrogen selenide in the same way which is equally as smelly but not one to do practicals with as it is even more acidic than the nasty H2S.
Se is an interesting element which is “photo conductive” meanings it can conduct electricity better when under bright light. this makes it good for “semiconductors” or light meters however Selenium’s ability to turn light energy to electrical energy means it is often used in solar cells. Apart from that I wouldn’t say that Se is used for anything spectacular in life- the usual paints and pigments as well as being used to color glass.
Selenium was discovered by a Swedish chemist J. Berzelius and is named after the Greek word for moon “selene”. A pretty name for perhaps what he thought was a pretty element- Se can form red black and gray allotropes 🙂 however i think that he named it “selenium” because of its solid silvery gray allotrope that to a 19th century chemist does look very “moon-like”/
George Bernard Shaw: “science is always wrong. it never solves a problem without creating 10 more”
Nearly wrote my critical essay on this quote. Think it is interesting how people make all sorts of claims on behalf of science thinking that science has everything sorted out, when actually we work by creating more problems to solve the problems we already have.
Thinking about the heart and dissection check out http://www.ted.com/talks/quyen_nguyen_color_coded_surgery.html
-awe inspiring video about how green Fluorescent proteins can be used in the treatment of cancer!
Whats even better is that Quyen Nguyen worked with Roger Y. Tsien who won the Nobel prize for Chemistry in 2008! 😀
Not quite chemistry but still great to see how the body works by examining a pigs heart!
From Teflon to PVC polymers are all around us. Plastic bags, windows, cooking utensils, clothes; all are made with certain types of polymers.
Probably one of the most incredible uses of polymers is in our air crafts and space ships. Without polymers we may not have the capacity or the resources to send the numerous crafts we do into space- nor fly around the world in quick and easy travel. One of the most fascinating of materials is fibre glass- which is a composite material.
Fibre glass is made up of the thermosetting polymer “polyester” and is re-enforced by added tiny strands of glass to the polymer. This makes it ideal for aircrafts as it is very strong but has an incredibly low mass. However, due to its composite nature fibreglass is an expensive material to manufacture.
Perhaps if we could make these desirable composite polymers easier and cheaper to produce, we would see more and more used for other consumer goods….
Kevlar. Its chemistry and it saves lives.
No its not anything to do with pharmaceuticals, nor is it anything to do with Agriculture.
When you think of chemistry that saves lives you tend to think of drug production, of cures for HIV, medical research, fertilizers, food programs for the meal-nourished. That is why i was surprised to learn that “Kevlar” was not one of these but a polymer with just an incredible amount of hydrogen bonds.
The key to Kevlar’s success in the usage of bullet proof vests is its strength- unlike the flimsy plastic that come to mind when we picture polymers Kevlar is actually 5 times stronger than steel, doesn’t corrode and can withstand extremely high temperatures.
The main reason for its strength is down to the large amount of hydrogen bonds in its structure which occur between the Hydrogen on the N-H and the highly electronegative oxygen attached to the carbon chain.
These bonds form all the way along the structure so giving it its intense strength. As well as this Kevlar is also strong due to “aromatic stacking” which is due to the Benzene rings in its polyamide chains.