Question of the day: Why does the egg float when it is put into salt water but when it is put into pure water, it will sink?
To solve this problem, we must understand how to derive at the density of an object. The formula is:
To solve this problem, we must understand how to derive at the density of an object. The formula is:
With this formula, we can solve the problem.
When the egg is placed into the pure water, the egg is more dense than the water, agree? As you all know, the object that is more dense will sink, which in this case, is the egg!
Then, why does the egg float when placed in SALT water? Simple: when the salt dissolves into the pure water, it adds mass. However, the volume of the water is still the same as the salt dissolved into the solvent ( water ). With added mass and no added volume, the density of salt water is now greater than the density of water.
Which is heavier, 1kg of styrofoam or 1kg of gold?
Ans: NONE! It is the same mass
Now, this: Which is less dense?
Ans: GOLD! Why?
Because gold has a smaller volume than the styrofoam although they have the same mass. So, gold is less dense.
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Cool Science Experiment
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The Vibration-power Floor Panel in Tokyo - Walk on it to Generate Electricity
Four panels of the vibration-power generator are laid onto the busy streets of Tokyo. Whoever steps on any of the panels will generate electicity.
This invention is by Kouhei Hayamizu. His goal is to generate electricity from vibration and sounds and to harness it for commercial use.
What he has done is he used the vibrations caused by passing vehicles on the Goshiki Zakura Ohashi Ohashi bridge to generate electricity to light up the bridge.
What an amazing discovery !
Source : The Young Scientists, Issue 91
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Cool Science Experiment
Ever thought of these question? Are egg shells fragile? Or do they have super strength? Most of the people would say, " Egg shells are definitely fragile!" They have just violated one rule in science: most of the time, nothing is definite. So, here I am, telling you exactly how to make a fragile egg shell to an egg shell with extraordinary strength.
Step 1: Wrap a strip of masking tape around the middle of 4 egg shell halves. Leave a small gap between the ends of the masking tape.
Step 2: Carefully, make a hole in the eggshell between the gap in the tape.
Step 3: Empty the insides into a cup. Keep the empty eggshells.
Step 4: Put the nail scissors into the hole.
Step 5: Cut around the middle of the eggshell covered with the masking tape.
Step 6: Seperate the halves.
Step 7: Trim off any jagged pieces of eggshell. Each one needs a straight edged bottom.
Step 8: Lay the eggshells, dome side up, so they make a sqaure.
Step 9: Place a piece of cardboard box on top.
Step 10: Stand a can on top of the cardboard.
What happens?
The eggshell won't crack, that is, after a few cans. The record is 11 cans! Can you beat that?
WHY?
Step 1: Wrap a strip of masking tape around the middle of 4 egg shell halves. Leave a small gap between the ends of the masking tape.
Step 2: Carefully, make a hole in the eggshell between the gap in the tape.
Step 3: Empty the insides into a cup. Keep the empty eggshells.
Step 4: Put the nail scissors into the hole.
Step 5: Cut around the middle of the eggshell covered with the masking tape.
Step 6: Seperate the halves.
Step 7: Trim off any jagged pieces of eggshell. Each one needs a straight edged bottom.
Step 8: Lay the eggshells, dome side up, so they make a sqaure.
Step 9: Place a piece of cardboard box on top.
Step 10: Stand a can on top of the cardboard.
What happens?
The eggshell won't crack, that is, after a few cans. The record is 11 cans! Can you beat that?
WHY?
- The strength of the egg is in its dome shape
- No single point in the dome supports the whole weight of the cans on top of it.
- The weight spreads along the curved walls to the wide base, allowing the egg shells to hold more weight.
I find this very interesting. It shows many things about Science itself. Science exists such that nothing is definite. You do not know what can happen without trying at all. That is why Scientists need to be open to new ideas, and take the time to try it out and prove it. Another example is holding up a pencil case full of stationery in it with a piece of paper. Most of us would be limited to just folding a piece of paper, or just simply say it is impossible. But it can be solved easily. The first mental block of people is to rely on their assumptions.
Thats the end. I hope you find this interesting too.
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Why leaves are green?
In primary school, we were told that leaves were green because of chlorophyll. Now that I am in secondary school, I found a better explanation of why leaves are green.
Chlorophyll absorbs the red and blue light from the sunlight that contacts the leaf. Light reflected from or transmitted through the leaf is deficient in red and blue light, so it appears green to our eyes. Green is the type of light used the least by chlorophyll. When a leaf has a high concentration of chlorophyll relative to the other pigments, the leaf appears green.
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The Vibration-power Floor Panel in Tokyo - Walk on it to Generate Electricity
Four panels of the vibration-power generator are laid onto the busy streets of Tokyo. Whoever steps on any of the panels will generate electicity.
This invention is by Kouhei Hayamizu. His goal is to generate electricity from vibration and sounds and to harness it for commercial use.
What he has done is he used the vibrations caused by passing vehicles on the Goshiki Zakura Ohashi Ohashi bridge to generate electricity to light up the bridge. What an amazing discovery !
Source : The Young Scientists, Issue 91
