Popular, Science, Nature and Tech

Have you ever wondered…why leaves change colour in autumn?

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.

Science, Nature and Tech

What is the Orionid Meteor Shower?

This October Earth will be passing through the tail of Halley’s comet, which will mean a shower of meteors flashing across the night sky. Our science editor Sam Gouldson explains.

What is Halley’s Comet?

A comet is a lump of rocky particles, ice and dust all bound together like a dirty snowball. When the comet nears a star, its surface transforms from a solid to a gas. The star’s light shines through these gases and makes them visible to observers as a fuzzy cloud around the comet’s centre, and a tail streaming out behind.

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What is Juno?

There has been a lot of excitement about the Juno probe this week, but what is it and what is its mission?

What is Juno?

Juno is a spacecraft designed and operated by NASA, the US space agency. It was launched from Cape Canaveral on the 5th August 2011 and has taken almost 5 years to travel the 716 million kilometres to Jupiter, the largest planet in our solar system. Juno is 3.5 metres in height, and when its solar arrays are extended it’s more than 20 metres across. These arrays are covered in more than 18,500 solar cells, which allows Juno to operate even when it’s at such a great distance from the Sun.

(Image: NASA)

Why is it called Juno?

In Roman mythology Juno was the Queen of the gods. She was married to the king, Jupiter, who wasn’t always well-behaved. Juno had to peer through the clouds to discover what he was up to; the spacecraft is called Juno because it will be looking beneath the clouds that cover the surface of the planet Jupiter.

Aboard the Juno craft are 3 models of Lego minifigures: Jupiter, Juno and Galileo, who discovered in 1610 that Jupiter had moons.

From left to right: Galileo, Juno and Jupiter. (Image: NASA/JPL-Caltech/LEGO).

What is it looking for?

Jupiter is enormous; it’s two and a half times larger than all the other planets in our solar system combined. It’s made entirely of gases and is believed to have no solid surface. The planet rotates at an immense speed, completing one rotation every ten hours, and telescopes have shown us that it has a cloudy atmosphere with colourful spots and stripes. The largest of these, known as the Great Red Spot, is a storm that is several times the size of Earth and has been raging for more than 300 years.

Jupiter. The Great Red Spot is clearly visible. (Image: NASA).

This mission is the first time that humans will be able to glimpse what lies beneath Jupiter’s cloudy atmosphere. The main objective is to understand how the planet formed and evolved, which will give us more information about the formation of gas giants as well as the rest of the solar system. Juno will also measure the quantities of water and ammonia within the atmosphere, examine the magnetic field that surrounds the planet, observe any polar auroras and measure the gravity to see whether a solid core may exist after all.

For more information about the Juno mission you can watch this video from Nasa, and have a look at the Juno mission webpage.

Art & History, Science, Nature and Tech

The Clifton suspension bridge: designed by a woman, built by Brunel

One of the best known landmarks in Bristol, UK, the Clifton suspension bridge first opened in 1864. It was built by the famous British engineer Isambard Kingdom Brunel, but it has recently become public knowledge that it was designed by a woman. Our science editor Sam Gouldson explains who she was and why her work isn’t more widely known.

Who really designed the bridge?

The Clifton suspension bridge was designed by a woman called Sarah Guppy. She was born Sarah Beach in 1770, but when she married her husband Samuel Guppy she took his name. She was one of the great British inventors of her time and the bridge isn’t the only thing she came up with.

What else did she design?

The invention that earned Sarah the most money was her device to prevent barnacles forming on the hulls of ships. Without barnacles the ships would be able to cut better through water and travel more quickly, and the Royal Navy paid her £40,000 for it. That may not sound like much for such a valuable design, but today it would be more than £2.3 million. Her other inventions included a kettle that not only boiled water for tea but could cook an egg and keep toast warm, a candle holder that could keep candles alight for longer and a way of treating boats so that they were more watertight. She also came up with the idea of planting willow and poplar trees on the embankments of new railways, to hold the earth together and prevent landslides.

Why isn’t she more famous?

Sarah lived during the Georgian and Victorian eras. In those times married women weren’t allowed to own property in their own name, and intellectual property such as Sarah’s inventions were no different. Her husband had to file the patents on her behalf, as the property of the Guppy family. The patent for her method of piling bridge foundations in order to create a new kind of bridge was filed in 1811, but she refused to charge others to use the idea because she felt it was for the benefit of the public. Thomas Telford, a civil engineer, used her design to build the Menai bridge in 1826, and when the competition to design the Clifton bridge was announced Sarah gave her work to Brunel. When she wrote to him to suggest the use of willow and poplar trees to reinforce railway embankments, she explained that she didn’t want the credit for her idea because she felt that women “must not be boastful”.

Featured image: Sage Solar/Flikr

Science, Nature and Tech

Why do we get Hiccups?

Everybody gets hiccups (also sometimes spelt ‘hiccoughs’). Even when babies are still in the womb they hiccup, which can feel very odd to their mother! But why do we get them and how can you stop them?

What are Hiccups?

Hiccups are caused by the diaphragm (pronounced DYE-uh-fram). This is a large, dome-shaped muscle that sits at the bottom of your chest cavity, below your lungs. When we breathe in the diaphragm tightens, helping to pull air into the lungs, and when it relaxes it forces the air back out again. Sometimes the diaphragm becomes irritated and instead of tightening smoothly it does it in a jerky way, which makes air suddenly rush into your throat. This air is stopped when it hits the voice box and makes the opening between the vocal cords close very suddenly. This is what produces the sound of the hiccup.