A lot of people have spent a very long time wondering what causes cancer – and scientists still can’t say for certain why an individual person might have it.
Marina del Castell/Flickr
I have worked on this problem for many years, and to be honest it still blows my mind to really think about just how complex it is.
Generations of giraffes.
It can actually be very tricky to define a species, but in the 1900s, scientists found a pretty good way.
If you went to Mars, you’d need to be able to survive an extremely punishing environment. This picture, taken by NASA’s Mars Exploration Rover Opportunity, gives you an idea.
NASA/JPL-Caltech/Cornell Univ./Arizona State Univ.
I've worked with NASA’s Mars Exploration Rover Project for 16 years. If you got yourself a ticket to Mars, here's how I'd advise you to prepare. And by the way, any mistake could kill you.
In fact, it’s not even the moths eating your clothes.
If you see moths and their larvae near your clothes, it's a sign that it's time to wash all your clothes and air them out in the sun.
How many times have you heard “get out of the way!” when someone is trying to change the channel?
Even the Voyager spacecraft are controlled remotely, 20 billion kilometres away. It takes 20 hours for instructions to travel from Earth to the spacecraft but we can do it -- using a remote.
As water vapour (gas) cools, it slows down. The small parts, the molecules, start to gather together, especially on cold things like a cool leaf.
When water turns from a gas into a liquid, it forms droplets. Whether those droplets are dew or rain depends on where the droplet forms.
Every magnet has two sides: a north pole and a south pole.
The energy needed to pull magnets apart comes from you, and you get it from the food you eat. And the plants or animals you eat get their energy from other plants and animals, or from the Sun. All energy comes from somewhere.
Nobody knows for sure - but it’s possible.
There are probably more than a million planets in the universe for every single grain of sand on Earth. That's a lot of planets. My guess is that there probably is life elsewhere in the Universe.
The sense of smell helps us know what and where things are, like yummy food. R. Suarez.
The parts of the brain that get 'smell signals' from the nose also do other things, such as storing memories or provoking emotions. That is why some smells can bring back old memories.
Children grow up to look somewhat like their parents.
Every human carries an instruction booklet with a very special code, called DNA. Our eyes cannot read the code, but our bodies can. The code tells our body what to do and how to look.
The Sun is a star – but it’s not the only one.
NASA/GSFC/Solar Dynamics Observatory
There are lots of places where it's much, much hotter than the Sun. And the amazing thing is that this heat also makes new atoms - tiny particles that have made their way long ago from stars to us.
Dropping leaves might seem like a waste, but plants are actually saving nutrients.
The composition of black and white in a magpie’s poo differs between species. Some splatter more of the uric acid (white), some have more black (indigestible solids). It depends on their diet.
Like reptiles, birds do not have two separate exits from the body. They have one, called the cloaca. It is quite similar to the human anus but the cloaca expels both indigestible bits and toxins.
When a fly’s feeling hungry, it will land on its food and vomit out a mix of saliva and stomach acids.
Bush flies and blowflies all vomit on their food, but other flies are a little more polite at the dinner table and don’t vomit at all.
Food helps recharge your batteries.
Just like a mobile phone, your body needs to be recharged every day. You need to eat food and drink water every day to keep your body going. Some foods are better than others at helping you stay well.
Don't try this at home, kids.
Dog skin is exactly the same as yours - depending on how much sun it’s exposed to, it can get darker and lighter.
Dog skin is exactly the same as yours and mine! It changes colour depending on how much light it's exposed to.
Perth air traffic control tower. As a pilot flies towards the destination, the air traffic control tower sends an interrogation signal. The aircraft automatically responds with a series of short pulses that let air traffic control know the identity of the plane and its altitude.
© Copyright Airservices Australia
Secondary radar is an important tool in the control of aircraft traffic, and helps make air travel safe. It was developed during dangerous times.
Running around like a…
There was once a chicken called Miracle Mike who lived for 18 months without a head: it's all to do with nerves.
More spelling problems came in when French scribes introduced new spelling conventions — their own of course, and not always helpful.
It was a rocky beginning for English spelling. Then things got worse.