The Week Junior - Science + Nature
HEADSCRATCHERS
Seeking answers to your science questions? Ask our resident expert, Peter Gallivan
Your toughest science questions are answered by our resident expert, plus find out why many animals of the same species look the same but humans don’t.
Hi, I’m Pete, and I love science and the natural world. I work at the Royal Institution (Ri) in London, where I organise exciting science events for young people. I’ve teamed up with The Week Junior Science+Nature to answer your burning science questions.
Why do some animals look the same but we humans look different?
Musfirah
Humans do show a huge variety in appearance. Faces in particular are very diverse and scientists think this these differences have evolved to make it easier to recognise individual people. From our origins as hunters on the plains of Africa almost 200,000 years ago, humans have always relied on each other for survival. Since vision is the main human sense, people distinguish each other by appearance.
Although other animals often seem very alike, they too can tell each other apart by appearance. Jane Goodall, a pioneering scientist who studied chimpanzee societies in the wild, learned with practice to recognise many different individual chimps based on their looks.
Not all animals use vision to tell each other apart, though. Dolphins use sounds and each dolphin has a unique whistling call. They use these a bit like a name to introduce themselves when they meet other dolphins. Belding’s ground squirrels use smells to work out who is who; family members smell more like themselves than strangers do. Relying on sound or smell means that visual differences are less important to these animals.
What are the horn-like things on a giraffe’s head called, and why do they have them?
Sophie
The bumps on a giraffe’s head are called ossicones and they are not technically horns. Horns like those on a reindeer are made of keratin – the same material that make up your hair and fingernails. A giraffe’s ossicones, in contrast, are actually made of solid bone. They are part of the skull and covered in skin and fur. A female giraffe’s ossicones are slightly smaller and more slender than a male’s and are topped with tufts of hair. Male okapis (the closest living relatives of giraffes) also have ossicones but females don’t.
Male giraffes use their ossicones when fighting. Making full use of their long neck, they swing their head around and thump it into the side of their competitor’s body in an unusual behaviour called “necking”. The blows are so powerful they can be heard 100 metres away.
How was the Earth created?
Ayush
Earth and the other planets formed from material that was left behind when the Sun itself was born. Around 4.6 billion years ago, a huge cloud of gas and dust floating in space began to collapse, thanks to gravity – the force that attracts objects to others packed with large amounts of matter. The Sun formed at the centre, surrounded by a thick disc of material. Within this disc, dust grains collided and stuck together, growing into larger rocky bodies with enough gravity of their own to draw in more material and grow like a rolling snowball. Gradually, these “protoplanets” became Earth and its neighbours.
Why do we hiccup and what are the best cures?
Chloe
Most people get hiccups every now and then and they are completely normal. They are caused by sudden movements of your diaphragm, a flat muscle under your lungs that helps you breathe. Most hiccups start for no clear reason but they can be caused by eating and drinking or by emotions like excitement or stress. Unfortunately, most so-called cures for hiccups are not very reliable. There’s no single solution that works for everyone but things you can try include sipping water, eating a lemon, breathing into a paper bag and holding your breath. Usually hiccups stop on their own – although one man had them for a recordbreaking 68 years.