British Council-The helix
Transcript of the podcast
I’d like to turn now to the object which is the main point of this talk: the helix. This is a fascinating mathematical object which touches many parts of our lives. Movement, the natural world, the manufactured world and our genetic make-up are all connected to the shape of the helix
A helix is a type of three-dimensional curve that goes around a central cylindrical shape in the form of a spiral, like a corkscrew or a spiral staircase. The helix is a very popular shape in nature because it is very compact. In fact, helices are sometimes referred to as ‘nature’s space saver’. In architecture too, the helix shape of a spiral staircase is an attractive option in buildings where space is very restricted
The most renowned type of helix is probably the double helix of DNA, or deoxyribonucleic acid. DNA is made of two helices that curve around each other, a bit like a twisted ladder. DNA contains the genetic information or ‘code’ that determines the development and functioning of all known living things. The helix shape is a very efficient way to store a long molecule like DNA in the limited space of a cell
There are different types of helices. Helices can twist clockwise, right-handed, or anti-clockwise, left-handed. An interesting experiment is to hold a clockwise helix, such as a corkscrew, up to a mirror. The clockwise helix appears to become counterclockwise
We can perceive examples of helices in many areas of our world. Spiral staircases, cables, screws and ropes can be right-handed or left-handed helices. A helix that goes around a cone is called a conical helix. Examples of conical helices are screws or the famous spiral ramp designed by the architect Frank Lloyd Wright in the Guggenheim Museum in New York
Helices are also prevalent in the natural world. The horns of certain animals, viruses, seashells and the structure of plants, flowers and leaves can all contain helices. The human umbilical cord is in fact a triple helix
With the discovery that the helix is the shape of the DNA molecule, it is not surprising that the helix is found in so many areas. It’s one of the most natural shapes in nature
Let’s turn our attention now to the mathematical description of the helix. You’ll need a pen and paper for the next part of the talk as I am going to give you some variables to write down. Take your time to notice the different
:Exercises
?Are the sentences true or false
.N1. The speaker starts the talk with two examples of helices found in nature
True
False
.N2. A helix is a three-dimensional object
True
False
.N3. The main advantage of a spiral staircase is its strength
True
False
.N4. DNA contains the genetic information for most, but not all, living things
True
False
.N5. A mirror image of a helix can appear to change direction
True
False
.N6. The screw is an example of a conical helix
True
False
.N7. Helices are much more common in manufactured objects than in natural objects
True
False
.N8. It is a mystery why there are so many helices in the world
True
False
:Answers
N1. False
N2. True
N3. False
N4. False
N5. True
N6. True
N7. False
N8. False
