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Why do we sleep?

Science
How do noise cancelling headphones work?
Just by covering your ears, headphones help block the sounds around you. But active noise cancellation takes a little bit more work. Different sounds have different waveforms. And a microphone on noise cancelling headphones registers the waveforms coming from the sounds aro...
Just by covering your ears, headphones help block the sounds around you. But active noise cancellation takes a little bit more work. Different sounds have different waveforms. And a microphone on noise cancelling headphones registers the waveforms coming from the sounds aro...
Just by covering your ears, headphones help block the sounds around you. But active noise cancellation takes a little...
- Posted on June 13, 2014
Why are lakes freshwater and oceans saltwater?
It has something to do with this leaky faucet. You see, rain falls on the land as fresh water. As this water flows downward, it ever so slightly erodes the rocks and soil. This causes an ever so slight amount of salt and minerals to dissolve in the water and continue downstream. Ev...
It has something to do with this leaky faucet. You see, rain falls on the land as fresh water. As this water flows downward, it ever so slightly erodes the rocks and soil. This causes an ever so slight amount of salt and minerals to dissolve in the water and continue downstream. Ev...
It has something to do with this leaky faucet. You see, rain falls on the land as fresh water. As this water flows do...
- Posted on June 2, 2014
Is fire a solid, a liquid or a gas?
The answer is none of the above. Contrary to what the ancient Greeks thought, not only is fire not one of four basic elements that make up everything in the universe, fire isn’t even a substance. It’s a process. As any good Boy Scout knows, to light a fire, you need thre...
The answer is none of the above. Contrary to what the ancient Greeks thought, not only is fire not one of four basic elements that make up everything in the universe, fire isn’t even a substance. It’s a process. As any good Boy Scout knows, to light a fire, you need thre...
The answer is none of the above. Contrary to what the ancient Greeks thought, not only is fire not one of four basic ...
- Posted on May 29, 2014
What happens to you in space without a space suit?
Bad things happen, my friends. Lots of bad things. Our bodies depend on Earth's atmosphere to survive. Not just for oxygen. The atmosphere protects us from ultraviolet radiation. It regulates temperatures. And it wraps us in a cocoon of lovely, lovely air pressure. In the v...
Bad things happen, my friends. Lots of bad things. Our bodies depend on Earth's atmosphere to survive. Not just for oxygen. The atmosphere protects us from ultraviolet radiation. It regulates temperatures. And it wraps us in a cocoon of lovely, lovely air pressure. In the v...
Bad things happen, my friends. Lots of bad things. Our bodies depend on Earth's atmosphere to survive. Not ju...
- Posted on May 22, 2014
New frogs found. And they “dance.”
Fourteen new species of dancing frogs have been found in the jungle mountains of southern India. The tiny amphibians earned their name with the unusual kicks they use to attract mates. One problem, though. The species declined in number during the 12 years in which Indian sc...
Fourteen new species of dancing frogs have been found in the jungle mountains of southern India. The tiny amphibians earned their name with the unusual kicks they use to attract mates. One problem, though. The species declined in number during the 12 years in which Indian sc...
Fourteen new species of dancing frogs have been found in the jungle mountains of southern India. The tiny amphi...
- Posted on May 22, 2014
Can you make a man out of a monkey?
Humans share ninety eight percent of their DNA with chimpanzees, so could you genetically engineer the rest to make it into a human? Settle down, we’re not making any human-animal hybrids around here. Even if we wanted to, it doesn’t mean we can. See, the important thin...
Humans share ninety eight percent of their DNA with chimpanzees, so could you genetically engineer the rest to make it into a human? Settle down, we’re not making any human-animal hybrids around here. Even if we wanted to, it doesn’t mean we can. See, the important thin...
Humans share ninety eight percent of their DNA with chimpanzees, so could you genetically engineer the rest to make i...
- Posted on May 19, 2014
Does the 5-second rule really work?
The 5-second rule states that food dropped on the floor for less than 5 seconds is still safe to eat. But to really answer the question, we need to ask another – how lucky do you feel? It can take less than 5 seconds for 150 to 8,000 bacteria like Salmonella to hop a ride...
The 5-second rule states that food dropped on the floor for less than 5 seconds is still safe to eat. But to really answer the question, we need to ask another – how lucky do you feel? It can take less than 5 seconds for 150 to 8,000 bacteria like Salmonella to hop a ride...
The 5-second rule states that food dropped on the floor for less than 5 seconds is still safe to eat. But to really a...
- Posted on May 16, 2014
Which animal lives longest?
Sticking with recorded history, the answer might surprise you. It’s not elephants, which live for about 30 or 40 years. It’s not giant tortoises either, even though they often ripen to be well over 100 years old. It’s not even that record-breaking, 507-year-old Arctic clam na...
Sticking with recorded history, the answer might surprise you. It’s not elephants, which live for about 30 or 40 years. It’s not giant tortoises either, even though they often ripen to be well over 100 years old. It’s not even that record-breaking, 507-year-old Arctic clam na...
Sticking with recorded history, the answer might surprise you. It’s not elephants, which live for about 30 or 40 ye...
- Posted on May 15, 2014
How do microwave ovens cook food?
Here's a hint – it's in the name of the machine, and it's not the word “oven.” Microwave ovens use microwaves. This spectrum ranges from radio waves and microwaves, to infra-red, visible light, ultraviolet, and x-rays. Now when you press start on your microwave oven, i...
Here's a hint – it's in the name of the machine, and it's not the word “oven.” Microwave ovens use microwaves. This spectrum ranges from radio waves and microwaves, to infra-red, visible light, ultraviolet, and x-rays. Now when you press start on your microwave oven, i...
Here's a hint – it's in the name of the machine, and it's not the word “oven.” Microwave ovens use microwaves. ...
- Posted on May 14, 2014
Why do we sleep?
That's a good question. But we don't have a good answer. We know that sleep is important. Without it, we get tired and irritable. We get headaches and suffer from lack of concentration. Our immune system suffers. After a number of days without sleep, we can hallucinate or ev...
That's a good question. But we don't have a good answer. We know that sleep is important. Without it, we get tired and irritable. We get headaches and suffer from lack of concentration. Our immune system suffers. After a number of days without sleep, we can hallucinate or ev...
That's a good question. But we don't have a good answer. We know that sleep is important. Without it, we get t...
- Posted on May 13, 2014