Hi everyone! Today, I will be sharing about my Science ace - "Dancing Raisins"
Materials needed
Raisins
Clear, colorless carbonated drink
Method
1)Pour the clear carbonated drink (sprite, h-two-o etc.) into a tall glass/ or just use the bottle itself
2)Put the raisins into the glass and see what happens
Observation
Raisins “dance” up and down the glass
Explanation
The raisins dance up and down due to density
Density is defined as its mass per unit volume.
When you put the raisins into the glass, you would see them sinking to the bottom of the glass.
As the carbonated drink releases carbon dioxide, the carbon dioxide stick to the rough surface of a raisin.
Raisin is lifted because of the increase in buoyancy.
When the raisin reaches the surface, the bubbles pop, and the carbon dioxide gas escapes into the air.
Raisin loses buoyancy and sink.
This rising and sinking of the raisins continues until most of the carbon dioxide has escaped, and the carbonated drink becomes un-carbonated.
Also, as the experiment goes on, the raisin gets soggy and becomes too heavy to rise to the surface.
Conclusion
Really fun, yet simple experiment that everyone can do :D
Tips
Try not to shake the bottle/can of carbonated drink too much, or it would lose its gas, and it would get really messy when you open it.
When I first tried the experiment, I put in a raisin that was too big and it would not “dance”. I tried another raisin and saw it dance a little, but it stopped after a while. In the end, I used a small raisin and it danced perfectly. The video footage is not very clear, but it could still be seen :D
Wednesday, August 10, 2011
Monday, August 8, 2011
Science Ace (Non-Newtonian Fluid)
Hi there everyone! Today, I will be sharing on my science ACE - Non Newtonian Fluids.
Materials used in experiment- corn-starch and water (ratio 1:1)
Steps to make a Non-Newtonian fluid:
1)Mix corn starch and water together in a pot or container
2)Mix evenly till the corn-starch acts like a liquid when you stir it slowly.
3)When you tap on the liquid with your finger, it shouldn't splash, but rather will become hard.
Personally, I added too much water at first and I had to wait for the corn-starch to settle down, before I could pour away the excess liquid. In the end, my mixture was a little too thick, but it would still be considered a Non-Newtonian fluid because it exhibited the properties of one.
Properties of a Non-Newtonian fluid
•A fluid whose flow properties differ in any way from those of Newtonian fluids.
•For example, when you poke your finger into a Non-Newtonian fluid, there would be a finger hole left there. This does not happen in Newtonian fluid.
•Hard when you hit it
•Acts like a liquid when you gently touch it.
Properties of a Newtonian fluid
•A Newtonian fluid is a fluid whose stress versus strain rate curve is linear and passes through the origin
•Think of this example - You have to pull the trigger on a water pistol to get the water to squirt out. To make the water to come out faster, you have to pull the trigger harder. Fluids resist flow. This phenomenon is known as viscosity. Therefore these fluids are called Newtonian fluids.
•Viscosity depends on temperature, pressure etc.
So, why does corn-starch mixture happen like this?
An example - Think of a busy sidewalk. The easiest way to get through a crowd of people is to move slowly and find a path between people. If you just took a running start and headed straight for the crowd of people, you would quickly slam into someone and you wouldn't get very far. This is similar to what happens in the corn-starch mixture. The corn-starch mixture acts like a crowd of people. Pressing your finger slowly into the mixture allows the corn-starch to move out of the way, but tapping the mixture quickly doesn't allow the solid corn-starch particles to slide past each other and out of the way of your finger.
The Newtonian fluid theory developed by Isaac Newton tells us that a fluid when applied pressure on, would not have any effect on the viscosity of it. However, corn-starch mixture and a lot of other fluids also act like this. Therefore, they are known as Non-Newtonian fluid.
This therefore explains what is seen in the video, when I hit the mixture, roll the mixture and try to take a lump of it out.
Other examples of Non-Newtonian fluids
Silly Putty
Ketchup
Chilled Caramel Toppings
Materials used in experiment- corn-starch and water (ratio 1:1)
Steps to make a Non-Newtonian fluid:
1)Mix corn starch and water together in a pot or container
2)Mix evenly till the corn-starch acts like a liquid when you stir it slowly.
3)When you tap on the liquid with your finger, it shouldn't splash, but rather will become hard.
Personally, I added too much water at first and I had to wait for the corn-starch to settle down, before I could pour away the excess liquid. In the end, my mixture was a little too thick, but it would still be considered a Non-Newtonian fluid because it exhibited the properties of one.
Properties of a Non-Newtonian fluid
•A fluid whose flow properties differ in any way from those of Newtonian fluids.
•For example, when you poke your finger into a Non-Newtonian fluid, there would be a finger hole left there. This does not happen in Newtonian fluid.
•Hard when you hit it
•Acts like a liquid when you gently touch it.
Properties of a Newtonian fluid
•A Newtonian fluid is a fluid whose stress versus strain rate curve is linear and passes through the origin
•Think of this example - You have to pull the trigger on a water pistol to get the water to squirt out. To make the water to come out faster, you have to pull the trigger harder. Fluids resist flow. This phenomenon is known as viscosity. Therefore these fluids are called Newtonian fluids.
•Viscosity depends on temperature, pressure etc.
So, why does corn-starch mixture happen like this?
An example - Think of a busy sidewalk. The easiest way to get through a crowd of people is to move slowly and find a path between people. If you just took a running start and headed straight for the crowd of people, you would quickly slam into someone and you wouldn't get very far. This is similar to what happens in the corn-starch mixture. The corn-starch mixture acts like a crowd of people. Pressing your finger slowly into the mixture allows the corn-starch to move out of the way, but tapping the mixture quickly doesn't allow the solid corn-starch particles to slide past each other and out of the way of your finger.
The Newtonian fluid theory developed by Isaac Newton tells us that a fluid when applied pressure on, would not have any effect on the viscosity of it. However, corn-starch mixture and a lot of other fluids also act like this. Therefore, they are known as Non-Newtonian fluid.
This therefore explains what is seen in the video, when I hit the mixture, roll the mixture and try to take a lump of it out.
Other examples of Non-Newtonian fluids
Silly Putty
Ketchup
Chilled Caramel Toppings
Homo floresiensis
Hi everyone! Today, I will be talking about the Homo floresiensis.
On the left is the skull of the Homo Floresiensis. On the right is the skull of the modern human.
The Homo floresiensis is a possible species of the genus "Homo". It was discovered in 2003 on the Indonesian Island of Flores. It was discovered in the "Liang Bua Cave". There were also 7 additional skeletons found in the cave and besides the skeletons, there were also stone tools recovered from the area.
What is so special about the Homo floresiensis is that is could be a possible species of the genus "homus" that was still surviving a short 12,000 years ago, making it the longest surviving non-modern human species besides the Neanderthals.
The anatomy of the skeleton extracted from the site is easily identifiable through its small body and small brain size. The specie was estimated to be at most 1.06m tall and it's range was far shorter than normal humans.
The findings could have numerous effects on modern understandings of the genus "Homus", though not very profound effects. However, it could tell us that the human species is more vulnerable than ever to the evolutionary forces than we think it could.
The Homo floresiensis was alive until 12,000 years ago and it is a very short time as compared to the whole life-span of the planet. Just imagine, 12,000 years from now and there is a whole new completely different species of humans! Humans are already probably starting to evolve now!
The only way we would know is to wait....
Here is the URL of the News article http://www.sciencenews.org/view/generic/id/333112/description/Taking_the_measure_of_a_hobbit
On the left is the skull of the Homo Floresiensis. On the right is the skull of the modern human.
The Homo floresiensis is a possible species of the genus "Homo". It was discovered in 2003 on the Indonesian Island of Flores. It was discovered in the "Liang Bua Cave". There were also 7 additional skeletons found in the cave and besides the skeletons, there were also stone tools recovered from the area.
What is so special about the Homo floresiensis is that is could be a possible species of the genus "homus" that was still surviving a short 12,000 years ago, making it the longest surviving non-modern human species besides the Neanderthals.
The anatomy of the skeleton extracted from the site is easily identifiable through its small body and small brain size. The specie was estimated to be at most 1.06m tall and it's range was far shorter than normal humans.
The findings could have numerous effects on modern understandings of the genus "Homus", though not very profound effects. However, it could tell us that the human species is more vulnerable than ever to the evolutionary forces than we think it could.
The Homo floresiensis was alive until 12,000 years ago and it is a very short time as compared to the whole life-span of the planet. Just imagine, 12,000 years from now and there is a whole new completely different species of humans! Humans are already probably starting to evolve now!
The only way we would know is to wait....
Here is the URL of the News article http://www.sciencenews.org/view/generic/id/333112/description/Taking_the_measure_of_a_hobbit
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