Simple Science Experiments

[jedamum]

kaydenbrown:

I hear there is this show called Brainaic.

yes, they do have it here in SG (i find their first season more entertaining and educational than the latter seasons). however, i find it not so suitable for kids and some of their experiments are a tad ridiculous and redundant.

[buds]

A tad?


A lot lah...
Especially the much
later episodes. :roll:
Some are funny too.

[RRMummy]

Hey, thanks jedamum. This is one of my fav topic. Here are some I found on the net which I think is interesting fun..



Egg in a Bottle Demonstration

The Power of Air Pressure

The egg in a bottle demonstration is an easy chemistry or physics demonstration you can do at home or in the lab. You set an egg on top of a bottle (as pictured). You change the temperature of the air inside the container either by dropping a piece of burning paper into the bottle or by directly heating/cooling the bottle. Air pushes the egg into the bottle.

Egg in a Bottle Materials
•\tpeeled hard-boiled egg (or soft-boiled, if a yolk mess interests you)
•\tflask or jar with opening slightly smaller than the diameter of the egg
•\tpaper/lighter or very hot water or very cold liquid
In a chemistry lab, this demonstration is most commonly performed using a 250-ml flask and a medium or large egg. If you are trying this demonstration at home, you can use a glass apple juice bottle. If you use too large of an egg, it will get sucked into the bottle, but stuck (resulting in a gooey mess if the egg was soft-boiled). I recommend a medium egg. An extra-large egg gets wedged in the bottle.

Perform the Demonstration
•\tMethod 1: Set a piece of paper on fire and drop it into the bottle. Set the egg on top of the bottle (small side pointed downward). When the flame goes out, the egg will get pushed into the bottle.
•\tMethod 2: Set the egg on the bottle. Run the bottle under very hot tap water. Warmed air will escape around the egg. Set the bottle on the counter. As it cools, the egg will be pushed into the bottle.
•\tMethod 3: Set the egg on the bottle. Immerse the bottle in a very cold liquid. I have heard of this being done using liquid nitrogen, but that sounds dangerous (could shatter the glass). I recommend trying ice water. The egg is pushed in as the air inside the bottle is chilled.

How It Works
If you just set the egg on the bottle, its diameter is too large for it to slip inside. The pressure of the air inside and outside of the bottle is the same, so the only force that would cause the egg to enter the bottle is gravity. Gravity isn't sufficient to pull the egg inside the bottle.
When you change the temperature of the air inside the bottle, you change the pressure of the air inside the bottle. If you have a constant volume of air and heat it, the pressure of the air increases. If you cool the air, the pressure decreases. If you can lower the pressure inside the bottle enough, the air pressure outside the bottle will push the egg into the container.
It's easy to see how the pressure changes when you chill the bottle, but why is the egg pushed into the bottle when heat is applied? When you drop burning paper into the bottle, the paper will burn until the oxygen is consumed (or the paper is consumed, whichever comes first). Combustion heats the air in the bottle, increasing the air pressure. The heated air pushes the egg out of the way, making it appear to jump on the mouth of the bottle. As the air cools, the egg settles down and seals the mouth of the bottle. Now there is less air in the bottle than when you started, so it exerts less pressure. When the temperature inside and outside the bottle is the same, there is enough positive pressure outside the bottle to push the egg inside.
Heating the bottle produces the same result (and may be easier to do if you can't keep the paper burning long enough to put the egg on the bottle). The bottle and the air are heated. Hot air escapes from the bottle until the pressure both inside and outside the bottle is the same. As the bottle and air inside continue to cool, a pressure gradient builds, so the egg is pushed into the bottle.

How to Get the Egg Out
You can get the egg out by increasing the pressure inside the bottle so that it is higher than the pressure of the air outside of the bottle. Roll the egg around so it is situated with the small end resting in the mouth of the bottle. Tilt the bottle just enough so you can blow air inside the bottle. Roll the egg over the opening before you take your mouth away. Hold the bottle upside down and watch the egg 'fall' out of the bottle. Alternatively, you can apply negative pressure to the bottle by sucking the air out, but then you risk choking on an egg, so that's not a good plan.

[RRMummy]

Rubber Eggs and Knotting a Bone!!


“A mad scientist can do much more with an egg than just eat it!”-Yasuhide Fumoto. A Mad Scientist can make a toy out of just about anything, including a boiled egg!

Children will be shown the Rubbery Egg and Knotted Bones which are prepared in advance. They will be told that these were made by soaking an egg in a common kitchen ingredient, vinegar, to dissolve its shell and make the egg rubbery enough that you can bounce it on the floor like a ball!

MATERIALS
•\tHard-boiled eggs
•\t1 raw egg
•\tThin chicken bones
•\tglass or jar, big enough to hold the egg
•\tvinegar

METHOD
1.\tPlace the egg in the glass or jar.
2.\tAdd enough vinegar to completely cover the egg.
3.\tWatch the egg. What do you see? Little bubbles may come off the egg as the acetic acid in the vinegar attacks the calcium carbonate of the eggshell. Over time the color of the eggs may change as well.
4.\tAfter 1 day, remove the egg and gently rinse the shell off of the egg with tap water.
5.\tAfter 3 – 4 days, how does the boiled egg feel? Try bouncing the egg on a hard surface. How high can you bounce your egg?
6.\tSoak raw eggs in vinegar for 1 day and compare the results. The eggs shell will become soft and flexible. You can gently squeeze these eggs, but it's not a great plan to try to bounce them on the floor.
7.\tImmerse the softened raw egg in water and observe. It'll absorb and expand via osmosis until the shell finally bursts.
8.\tSoak the thin bones in vinegar and observe the next day.

HOW IT WORKS?
Eggs contain something called \"calcium carbonate\". This is what makes them hard. Vinegar is an acid known as acetic acid. When calcium carbonate (the egg) and acetic acid (the vinegar) combine, a chemical reaction takes place and carbon dioxide (a gas) is released. This is what the bubbles are made of.
The chemical reaction keeps happening until all of the carbon in the egg is used up -- it takes about a day. When you take the egg out of the vinegar it's soft because all of the carbon floated out of the egg in those little bubbles.
Leave the same egg sitting out on the table for another day. Now feel it again. It's hard! The calcium left in the egg shell stole the carbon back from the carbon dioxide that's in the air we breathe.
What makes our bones hard? That's right! Calcium carbonate -- the same thing that made the egg shells hard. Take some thin chicken bones and drop them in vinegar for a day. Soaking chicken bones in vinegar will soften them so that they will become rubbery and flexible. Take them out and they'll be soft just like the egg shells were. Now you can tie them in a knot, just like a piece of string. Leave them sitting out on the table and they'll get hard again!
Encourage children to bring home their specimen to stump mom and dad!

EXTRA EGG FACTS

Q:\tWhat chemical reaction causes an egg to become hard-boiled?
A:\tThe chemical reaction is caused by the conflict of the sulphur from the yolk and the chemicals in the albumen in the white. This is why hard-boiled eggs get that very unappetizing green ring between the white and yolk.

[RRMummy]

HOMEMADE LAVA-SPEWING VOLCANO


MATERIALS
•\tEmpty 2-liter bottle /jar
•\tSalt dough or soil
•\tTray
•\tBaking soda
•\tLiquid dish soap
•\tWhite vinegar
•\tRed food coloring

METHOD
1.\tUse a large tray to make the base, to prevent the lava from staining surfaces during eruptions.
2.\tUse salt dough or soil to form a mountain around an empty 2-liter bottle placed upright at the center of the tray. Be sure to leave the lid off.
3.\tForm the model volcano's open top tightly around the mouth of the bottle.
4.\tMix 1 tbsp. liquid dish washing soap, 1 tbsp. baking soda and a few drops of red food coloring in a cup.
5.\tPour the mixture carefully into the bottle.
6.\tSet the volcano in an open area, preferably outside.
7.\tPour 1/4 c. white vinegar into the bottle and stand back to watch their volcano erupt!

p/s can also skip step 1-3.

The chemical reaction

NaHCO3 + CH3COOH --> Na+ + H2O + CO2 + CH3COO-
Carbon dioxide is released creating the fizz.
(Also actually released from Volcanos)

I would like the children to enter this virtual simulation website together to create and explore their own volcanic eruptions by varying the conditions (viscosity and gas) of a volcano.
http://kids.discovery.com/games/pompeii/pompeii.html

For additional information, this very informative website will be provided to children for exploring the topic – VOLCANO at their own time.
http://www.volcanolive.com/index.html

[RRMummy]

Enjoy!! When I have time I load up some more of my collections.. stay tuned..

[kaydenbrown]

buds:

A tad?


A lot lah...
Especially the much
later episodes. :roll:
Some are funny too.

Oh really..haha.. i thought kids here would learn a lot from it.

[Gund]

Hi All


With regards to the experiment on surface tension of water, might be good to teach your child to apply that concept instead of just learning it. In Science exam nowadays, application of concepts is v important.

For e.g., how does spraying insecticide on water kill the mosquito larva and pupa? It's a common misconception among kids that the breathing tubes are blocked so the larva and pupa died because they cannot take in air, but in actual fact, it's because insecticide lowers the surface tension and cause the larva and pupa to drown.
Plus you can also introduce the idea of how some insects seem to be able to float or walk on water surface like the water skater. Hope this information is helpful to you.

[krazy]

Thanks for the ideas! i will try out some of them during the hols!


Some months ago, I did some simple experiments with my girl too. of course, the classic volcano, crystal formation and density.

Growing crystals
http://preciouscheryl.blogspot.com/2009/10/growing-crystals.html

Density
http://preciouscheryl.blogspot.com/2009/10/does-egg-float.html

Volcano
http://preciouscheryl.blogspot.com/2009/09/volcano.html

[Fongg]

Sounded really cool.

Since its holiday, I will give it a try with my kids.

Thanks for the info