Autumn is a season of change; the weather gets colder, there’s less daylight and leaves change colour and fall from plants. But why does this happen?
Why Do Plants Have Leaves?
Leaves contain a chemical called chlorophyll (pronounced KLO-ro-fil), which as well as giving them their lovely green colour also helps create food for the plant. The leaves act like tiny solar panels, and use the sun’s energy to convert water (from the ground) and a gas called carbon dioxide (from the air) into sugar and oxygen. This process is called photosynthesis (pronounced foto-SIN-theh-sis), and the sugar is what the plant lives on.
The voting system in the US election often confuses people. What is an Electoral College, and what is the difference between the ‘popular vote’ and the ‘electoral college vote’? Who are the people who work in Congress, and what is the difference between the Senate and the House of Representatives? We take a closer look and answer these and other questions, in a kid-friendly way.
Dengue (pronounced den-gee) fever affects between 50-100 million people each year, with around 25,000 people dying from the disease. It’s most common in south America and parts of Africa, and is also known as breakbone fever because it causes such intense pain in the bones. Dengue fever is a virus that’s spread by mosquitoes, and there is no vaccine or effective drug treatment to prevent or cure it.
Spaghettieis (as they call it in Germany) belongs to German summers like sunshine and open-air swimming pools! In almost every town in the country, you will find an ice cream parlour that sells this delicacy. But what is Spaghetti Ice?
You may think that combining spaghetti and ice [cream], that it must have been invented in Italy, and you are almost right. It was invented by a man called Dario Fontanella, the son of Italian immigrants in Germany.
When we talk about electric batteries, we often talk about voltage. But did you know that this word is named after the person who invented the first electric battery? First, let’s take a look at what a volt is, and then we’ll find out more about the guy who gave the ‘volt’ its name.
What is a Volt?
A volt is defined as a unit of electric potential and electromotive force, and voltage refers to the number of those units. That sounds a lot more complicated than it is! If you think of the water in a tap being like the electricity running through a wire, the voltage means the amount of pressure. This video is quite long but explains it very well.
Why are Volts Called Volts?
Alessandro Volta
The term actually comes from a name. It was coined in honour of Italian physicist Alessandro Volta, who is recognised as the inventor of the first electric battery. During the 1790s, Volta worked on the theories of electricity of the day.
Volta disagreed with the theory proposed by fellow Italian scientist Galvani that electricity was generated by animal tissue. Instead of experimenting on frogs or other animals, Volta did experiment after experiment with metals.
His persistence paid off, and in 1800, he invented the world’s first battery, known as the ‘voltaic pile’.
The Voltaic Pile
This voltaic pile was simple but ingenious. It consisted of a pile of zinc and silver discs. But alternating between them was a piece of cardboard, or a piece of cloth, that had been soaked in saltwater.
There was a wire that connected the zinc disc on the bottom to the silver disc on the top, and this wire was capable of producing sparks.
What else Did Volta Invent?
The invention of the first electric battery brought Volta the most fame and recognition, but he also made other discoveries. He invented the electrophorus, a device that could transfer an electrical charge to other objects, as well as an electrical condensor, and the voltaic cell.
He is also known for having discovered and isolated methane gas. After his death, the volt and voltage were named in his memory.
What about Galvani?
Luigi Galvani
Yet there is one more twist to the tale. Volta’s longstanding colleague Galvani of the animal electricity theory also left his name in our language. When we say ‘galvanise’ or ‘galvanism’, that is where it comes from.
Despite their differing theories, there was no rivalry between the two scientists. They were both more concerned with the pursuit of knowledge than with whose theory would prove to be right, and it was Volta who first coined the word ‘galvanismo’ in Italian.
