Nov 16, 2011
Nov 11, 2011
Aug 26, 2011
Aug 15, 2011
Breath on a cold day
Your breath is warmer than the air outside on a cold day. When you breathe in, your lungs warm up the air because your body has a constant temperature of 37 Degrees Celsius. If the temperature of your breath suddenly decreases (like when you breathe out), condensation can occur, which is a bit like steam. This makes your breath turn to fog and dust in the air also helps you see it.
This is why you see your breath on a cold day.
Aug 12, 2011
Did you know?
Earth's human population is set to reach seven billion this year; twice as many people as there were in 1960. On current estimates, a global population of 10 billion is possible by the end of the century.
Jul 26, 2011
Glowing animal eyes and human red-eye in photos
Cats, dogs, and many nocturnal animals appear to have glowing eyes at night. This is because the back of their eyeballs include a special reflective layer. This helps animals (cats in this case) see better in low light by working like a mirror to reflect the light back through the eyes, giving them a second chance to absorb the light. These glowing colours are easier to see at night because the animal's pupils are wider.
Humans don't have this layer. That partially explains why when photos are taking using a flash, people's eyes have red spots in them. This is caused by the light from the flash traveling through the pupil and lighting up the blood-cell rich retina at the back of our eyes.
The secret behind so-called "red-eye-reducing cameras" is that they use two quick flashes instead of one. The theory being that the first flash will cause the subject's pupils to close up a little and let in less light, while the second will be used for the actual picture.
Humans don't have this layer. That partially explains why when photos are taking using a flash, people's eyes have red spots in them. This is caused by the light from the flash traveling through the pupil and lighting up the blood-cell rich retina at the back of our eyes.
The secret behind so-called "red-eye-reducing cameras" is that they use two quick flashes instead of one. The theory being that the first flash will cause the subject's pupils to close up a little and let in less light, while the second will be used for the actual picture.
Jul 1, 2011
The Top 10 most dangerous animals in the world...look out!
1. Box Jellyfish
The top prize for “The World Most Venomous Animal,” would go to the Box Jellyfish. It has caused at least 5,567 recorded deaths since 1954. Their venom is among the most deadly in the world. It’s toxins attack the heart, nervous system, and skin cells. And the worst part of it is that jelly box venom is so overpoweringly painful, that human victims go in shock, drown or die of heart failure before even reaching shore. Survivors experience pain weeks after the contact with box jellies.
You have virtually no chance to survive the venomous sting, unless treated immediately. After a sting, vinegar should be applied for a minimum of 30 seconds. Vinegar has acetic acid, which disables the box jelly’s nematocysts that have not yet discharged into the bloodstream (though it will not alleviate the pain). Wearing panty hose while swimming is also a good prevention measure since it can prevent jellies from being able to harm your legs.
Jelly box can be found in the waters around Asia and Australia.
2. King Cobra
The King Cobra (Ophiophagus hannah) is the world’s longest venomous snake – growing up to 5.6 m (18.5 ft) in length. Ophiophagus, literally means “snake-eater” as it eats other snakes. One single bite of this deadly snake can easily kill a human. This snake is even capable of killing a full-grown Asian Elephant within 3 hours if the larger animal is bitten in a vulnerable area such as the trunk.
It’s venom is not as toxic as other venomous snakes, but King Cobra is capable of injecting 5 times more venom than black mamba and can result in mortality up to 5 times faster than that of the black mamba. It is quite widespread, ranging across South and South-east Asia, living in dense highland forests.
3. Marbled Cone Snail
This little beautiful looking Marbled Cone snail can be as deadly as any other animal on this list. One drop of its venom is so powerful that it can kill more than 20 humans. If you ever happen to be in warm salt water environment (where these snails are often found) and see it, don’t even think of picking it up. Of course, the true purpose of its venom is to catch its prey.
Symptoms of a cone snail sting can start immediately or can be delayed in onset for days. It results in intense pain, swelling, numbness and tingling. Severe cases involve muscle paralysis, vision changes and breathing failure. There is no antivenom. However, only about 30 human deaths have been recorded from cone snail envenomation.
4. Blue-Ringed Octopus
The Blue-Ringed Octopus is very small, only the size of a golf ball, but its venom is so powerful that can kill a human. Actually it carries enough poison to kill 26 adult humans within minutes, and there is no antidote. They are currently recognized as one of the world’s most venomous animals.
Its painless bite may seem harmless, but the deadly neurotoxins begin working immediately resulting in muscular weakness, numbness, followed by a cessation and breathing and ultimately death.They can be found in tide pools in the Pacific Ocean, from Japan to Australia.
5. Death Stalker Scorpion
Contrarily to the popular belief most of the scorpions are relatively harmless to humans as stings produce only local effects (pain, numbness or swelling). However, the Death Starker Scorpion is highly dangerous species because its venom is a powerful cocktail of neurotoxins which causes an intense and unbearable pain, then fever, followed by coma, convulsions, paralysis and death. Fortunately, while a sting from this scorpion is extremely painful, it would be unlikely to kill a healthy, adult human. Young children, the old, or infirm (with a heart condition) are at the biggest risk.Death stalker scorpions are spread in North Africa and Middle East.
6. Stonefish
Maybe Stonefish would never win a beauty contest, but it would definitely win the top prize for being “The World's Most Venomous Fish”. Its venom causes such a severe pain that the victims of its sting want the affected limb to be amputated. It is described as the worst pain known to man. It is accompanied with possible shock, paralysis, and tissue death. If not given medical attention within a couple of hours it can be fatal to humans.
Stonefish stores its toxins in gruesome-looking spines that are designed to hurt would-be predators.Stonefish mostly live above the tropic of Capricorn, often found in the shallow tropical marine waters of the Pacific and Indian oceans, ranging from the Red Sea to the Queensland Great Barrier Reef.
7. The Brazilian wandering spider
The Brazilian Wandering Spider (Phoneutria) or banana spider appears in the Guinness Book of World Records 2007 for the most venomous spider and is the spider responsible for most human deaths.
This spider is believed to have the most potent neurotoxic venom of any living spider. Only 0.006mg is sufficient to kill a mouse. They are also so dangerous because of their wandering nature. They often hide during daytime in highly populated areas inside houses, clothes, boots, and cars.
8. Inland Taipan
The prize for “The World’s Most Venomous Snake” goes to the Inland Taipan of Australia. Just a single bite from this snake contains enough venom to kill 100 human adults or an army of 250,000 mice. Its venom is at least 200 – 400 times more toxic than a common cobra. The Inland Taiwan’s extremely neurotoxic venom can kill an adult human in as little as 45 minutes. Fortunately this snake is very shy and there have been no documented human fatalities (all known bites were treated with antivenin).
9. Poison Dart Frog
If you ever happen to be running through the rain forests somewhere in Central or South America, do not ever pick up beautiful and colorful frogs – it can be the Poison Dart Frog. This frog is probably the most poisonous animal on earth.The 2 inch long (5cm) golden poison dart frog has enough venom to kill 10 adult humans or 20,000 mice. Only 2 micrograms of this lethal toxin (the amount that fits on the head of a pin) is capable of killing a human or other large mammal. They are called “dart frogs” because indigenous Amerindians’ use of their toxic secretions to poison the tips of their blow-darts. Poison dart frogs keep their poison in their skins and will sicken or kill anybody who touches or eats it.
10. Puffer Fish
Puffer Fish are the second most poisonous vertebrate on earth (the first one is golden dart Frog). The meat of some species is a delicacy in both Japan (as fugu) and Korea (as bok-uh) but the problem is that the skin and certain organs of many puffer fish are very poisonous to humans.
This puffy fish produce rapid and violent death..Puffer’s poisoning causes deadening of the tongue and lips, dizziness, vomiting, rapid heart rate, difficulty breathing, and muscle paralysis. Most of the victims die after four to 24 hours. There is no known antidote, most deaths from fugu happen when untrained people catch and prepare the fish.
Statistics show that there were 20 to 44 incidents of fugu poisoning per year between 1996 and 2006 in all of Japan and up to six incidents per year led to death. Since Fugu’s poison can cause near instantaneous death, only licensed chefs are allowed to prepare it.
The top prize for “The World Most Venomous Animal,” would go to the Box Jellyfish. It has caused at least 5,567 recorded deaths since 1954. Their venom is among the most deadly in the world. It’s toxins attack the heart, nervous system, and skin cells. And the worst part of it is that jelly box venom is so overpoweringly painful, that human victims go in shock, drown or die of heart failure before even reaching shore. Survivors experience pain weeks after the contact with box jellies.
You have virtually no chance to survive the venomous sting, unless treated immediately. After a sting, vinegar should be applied for a minimum of 30 seconds. Vinegar has acetic acid, which disables the box jelly’s nematocysts that have not yet discharged into the bloodstream (though it will not alleviate the pain). Wearing panty hose while swimming is also a good prevention measure since it can prevent jellies from being able to harm your legs.
Jelly box can be found in the waters around Asia and Australia.
2. King Cobra
The King Cobra (Ophiophagus hannah) is the world’s longest venomous snake – growing up to 5.6 m (18.5 ft) in length. Ophiophagus, literally means “snake-eater” as it eats other snakes. One single bite of this deadly snake can easily kill a human. This snake is even capable of killing a full-grown Asian Elephant within 3 hours if the larger animal is bitten in a vulnerable area such as the trunk.
It’s venom is not as toxic as other venomous snakes, but King Cobra is capable of injecting 5 times more venom than black mamba and can result in mortality up to 5 times faster than that of the black mamba. It is quite widespread, ranging across South and South-east Asia, living in dense highland forests.
3. Marbled Cone Snail
This little beautiful looking Marbled Cone snail can be as deadly as any other animal on this list. One drop of its venom is so powerful that it can kill more than 20 humans. If you ever happen to be in warm salt water environment (where these snails are often found) and see it, don’t even think of picking it up. Of course, the true purpose of its venom is to catch its prey.
Symptoms of a cone snail sting can start immediately or can be delayed in onset for days. It results in intense pain, swelling, numbness and tingling. Severe cases involve muscle paralysis, vision changes and breathing failure. There is no antivenom. However, only about 30 human deaths have been recorded from cone snail envenomation.
4. Blue-Ringed Octopus
The Blue-Ringed Octopus is very small, only the size of a golf ball, but its venom is so powerful that can kill a human. Actually it carries enough poison to kill 26 adult humans within minutes, and there is no antidote. They are currently recognized as one of the world’s most venomous animals.
Its painless bite may seem harmless, but the deadly neurotoxins begin working immediately resulting in muscular weakness, numbness, followed by a cessation and breathing and ultimately death.They can be found in tide pools in the Pacific Ocean, from Japan to Australia.
5. Death Stalker Scorpion
Contrarily to the popular belief most of the scorpions are relatively harmless to humans as stings produce only local effects (pain, numbness or swelling). However, the Death Starker Scorpion is highly dangerous species because its venom is a powerful cocktail of neurotoxins which causes an intense and unbearable pain, then fever, followed by coma, convulsions, paralysis and death. Fortunately, while a sting from this scorpion is extremely painful, it would be unlikely to kill a healthy, adult human. Young children, the old, or infirm (with a heart condition) are at the biggest risk.Death stalker scorpions are spread in North Africa and Middle East.
6. Stonefish
Maybe Stonefish would never win a beauty contest, but it would definitely win the top prize for being “The World's Most Venomous Fish”. Its venom causes such a severe pain that the victims of its sting want the affected limb to be amputated. It is described as the worst pain known to man. It is accompanied with possible shock, paralysis, and tissue death. If not given medical attention within a couple of hours it can be fatal to humans.
Stonefish stores its toxins in gruesome-looking spines that are designed to hurt would-be predators.Stonefish mostly live above the tropic of Capricorn, often found in the shallow tropical marine waters of the Pacific and Indian oceans, ranging from the Red Sea to the Queensland Great Barrier Reef.
7. The Brazilian wandering spider
The Brazilian Wandering Spider (Phoneutria) or banana spider appears in the Guinness Book of World Records 2007 for the most venomous spider and is the spider responsible for most human deaths.
This spider is believed to have the most potent neurotoxic venom of any living spider. Only 0.006mg is sufficient to kill a mouse. They are also so dangerous because of their wandering nature. They often hide during daytime in highly populated areas inside houses, clothes, boots, and cars.
8. Inland Taipan
The prize for “The World’s Most Venomous Snake” goes to the Inland Taipan of Australia. Just a single bite from this snake contains enough venom to kill 100 human adults or an army of 250,000 mice. Its venom is at least 200 – 400 times more toxic than a common cobra. The Inland Taiwan’s extremely neurotoxic venom can kill an adult human in as little as 45 minutes. Fortunately this snake is very shy and there have been no documented human fatalities (all known bites were treated with antivenin).
9. Poison Dart Frog
If you ever happen to be running through the rain forests somewhere in Central or South America, do not ever pick up beautiful and colorful frogs – it can be the Poison Dart Frog. This frog is probably the most poisonous animal on earth.The 2 inch long (5cm) golden poison dart frog has enough venom to kill 10 adult humans or 20,000 mice. Only 2 micrograms of this lethal toxin (the amount that fits on the head of a pin) is capable of killing a human or other large mammal. They are called “dart frogs” because indigenous Amerindians’ use of their toxic secretions to poison the tips of their blow-darts. Poison dart frogs keep their poison in their skins and will sicken or kill anybody who touches or eats it.
10. Puffer Fish
Puffer Fish are the second most poisonous vertebrate on earth (the first one is golden dart Frog). The meat of some species is a delicacy in both Japan (as fugu) and Korea (as bok-uh) but the problem is that the skin and certain organs of many puffer fish are very poisonous to humans.
This puffy fish produce rapid and violent death..Puffer’s poisoning causes deadening of the tongue and lips, dizziness, vomiting, rapid heart rate, difficulty breathing, and muscle paralysis. Most of the victims die after four to 24 hours. There is no known antidote, most deaths from fugu happen when untrained people catch and prepare the fish.
Statistics show that there were 20 to 44 incidents of fugu poisoning per year between 1996 and 2006 in all of Japan and up to six incidents per year led to death. Since Fugu’s poison can cause near instantaneous death, only licensed chefs are allowed to prepare it.
Jun 29, 2011
What are scabs?
What are scabs for, and is it OK to pick them?
Scabs put a lid on your cuts and scrapes, keeping blood in and nasty bacteria out. And, although it is fun, picking your scabs is dangerous, as it does the exact opposite.
So why is it dangerous to pick them?
Because scabs are like temporary plasters that cover your cuts until the skin has a chance to grow back underneath. They fall off on their own when the repairs are complete. Pick them off any sooner, and you risk opening up the wound again. At best, this will mean you just form another scab, so the wound takes longer to heal than it would have. But the second scab may be even bigger than the first, and is more likely to leave a permanent scar on your skin when it finally comes off.At worst, the wound could become infected, and lead to much bigger problems.
Like what? What’s the big deal about a little cut?
Ordinarily, nothing. This is because your body has a strong immune system and a clever system of blood clotting to prevent too much blood loss from the cut. When you get cut, the cells nearby release signals that start two major chain reactions. One chain reaction brings immune cells to the area to fight off any bacteria trying to get in through the cut. These are white blood cells that drift around in your bloodstream waiting for an attack. Some of them, called macrophages, can punch holes in the bacteria or eat them whole and digest them with acids. Others, called B-Cells, make special proteins called antibodies, which surround the bacteria with white helper cells and summon killer cells to destroy them.So why do we get scabs?
Scabs are made of the bits left over from this battle – the dead bacteria and immune cells – plus a special protein called fibrin. Fibrin is the end result of the other chain reaction – the one that leads to a blood clot. Again, when the wound occurs, special blood cells (this time called platelets) stick together and react with other proteins called clotting factors to build a clot. This clot is made from fibrin, a stringy protein that stretches across the wound, pulls the edges together and plugs the gap between them. This helps to stop any more blood from escaping, but also stops bacteria getting in.What happens if they do?
It depends on what type of bacteria. Some of them we can fight off easily enough, and the wound heals over normally. Others, like the clostridium bacteria that cause gas gangrene, can dodge the immune system long enough to do serious damage. So you could end up losing an entire leg or arm from one infected cut! Worse still, if bacteria makes it into the bloodstream, it can travel around the body to other organs like your liver, heart or brain, doing damage there instead. And you really don’t want that to happen.Yikes! I’m never picking a scab again!
If you’re healthy, and you keep the cut clean, none of this should be a problem. But the scab is there for a reason, and it’ll fall off on its own when it’s ready. Until then, just enjoy it. Admire the colours, impress your friends... but leave it alone!From: http://www.sciencemuseum.org.uk/onlinestuff/snot/what_are_scabs_for_and_is_it_OK_to_pick_them.aspx
Jun 22, 2011
Penicillin Research
Hi Year 5 girls,
Here are some links to help you research the scientists that helped to discover penicillin:
Howard Florey
http://www.abc.net.au/science/slab/florey/story.htm
http://encyclopedia.kids.net.au/page/ho/Howard_Walter_Florey
http://www.asap.unimelb.edu.au/bsparcs/exhib/nobel/florey.htm
Ernst Chain
http://www.scienceheroes.com/index.php?option=com_content&view=article&id=150&Itemid=149
http://www.discoveriesinmedicine.com/General-Information-and-Biographies/Chain-Ernst-Boris.html
http://www.pbs.org/wgbh/aso/databank/entries/bmchai.html
Alexander Fleming
http://www.bbc.co.uk/history/historic_figures/fleming_alexander.shtml
http://www.pbs.org/wgbh/aso/databank/entries/bmflem.html
http://www.myhero.com/go/hero.asp?hero=a_fleming
Here are some links to help you research the scientists that helped to discover penicillin:
Howard Florey
http://www.abc.net.au/science/slab/florey/story.htm
http://encyclopedia.kids.net.au/page/ho/Howard_Walter_Florey
http://www.asap.unimelb.edu.au/bsparcs/exhib/nobel/florey.htm
Ernst Chain
http://www.scienceheroes.com/index.php?option=com_content&view=article&id=150&Itemid=149
http://www.discoveriesinmedicine.com/General-Information-and-Biographies/Chain-Ernst-Boris.html
http://www.pbs.org/wgbh/aso/databank/entries/bmchai.html
Alexander Fleming
http://www.bbc.co.uk/history/historic_figures/fleming_alexander.shtml
http://www.pbs.org/wgbh/aso/databank/entries/bmflem.html
http://www.myhero.com/go/hero.asp?hero=a_fleming
Jun 21, 2011
Why do you appear up-side-down in a spoon?
Now think for a minute about a curved reflective surface, like a silver doorknob or one of those mirrors in a Fun House. Because these surfaces are curved and bent, the light of an image that is reflected by them gets curved and bent too! That’s why when you look into them, you end up with a silly balloon head or a big round belly!
The image reflected by a spoon works the same way! Because a spoon is bowl-shaped and curved, it doesn’t reflect your image straight back at you like a mirror. The reason you end up looking upside-down on the front of a spoon is that the metal bends inwards so much that bottom of the spoon ends up pointed towards your forehead and the top of the spoon ends up pointed towards your chin or your neck! This means the image you see reflected is bent and unusual too – your chin or neck is reflected at the bottom and your forehead is reflected at the top: You’re upside down!
Jun 20, 2011
Jun 17, 2011
What does yeast look like?
This is what one yeast cell looks like:
And thousands together under a microscope:
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