Chemical Experiments I
Autor: Gilson Silva  Costa | Publicado: 2012-01-08T17:08:00-03:00

Alguns experimentos de quimica. Além de ser uma ótima atividade de leitura e interpretação de texto é uma ótima oportunidade para realizar um projeto interdisciplina com os docentes de quimica.

# 1 - Mixing Oil
and Water




Some things
just don't get along well with each other. Take oil and water as an example,
you can mix them together and shake as hard as you like but they'll never
become friends.....or will they? Take this fun experiment a step further and
find out how bringing oil and water together can help you do your dishes.



&nbsp;What you'll
need:


&nbsp;&nbsp;&nbsp;&nbsp; * Small soft drink bottle


&nbsp;&nbsp;&nbsp; * Water


&nbsp;&nbsp;&nbsp; * Food colouring


&nbsp;&nbsp;&nbsp; * 2 tablespoons of cooking oil


&nbsp;&nbsp;&nbsp; * Dish washing liquid or detergent


&nbsp;Instructions:

&nbsp;&nbsp; 1. Add a few drops of food colouring to the
water.




&nbsp;&nbsp; 2. Pour about 2 tablespoons of the coloured
water along with the 2 tablespoons of cooking oil into the small soft drink
bottle.


&nbsp;&nbsp; 3. Screw the lid on tight and shake the
bottle as hard as you can.


&nbsp;&nbsp; 4. Put the bottle back down and have a look,
it may have seemed as though the liquids were mixing together but the oil will
float back to the top.


&nbsp;What's
happening?


While water
often mixes with other liquids to form solutions, oil and water does not. Water
molecules are strongly attracted to each other, this is the same for oil,
because they are more attracted to their own molecules they just don't mix
together. They separate and the oil floats above the water because it has a lower
density.




If you
really think oil and water belong together then try adding some dish washing
liquid or detergent. Detergent is attracted to both water and oil helping them
all join together and form something called an emulsion. This is extra handy
when washing those greasy dishes, the detergent takes the oil and grime off the
plates and into the water, yay!





# 2 - &nbsp;Make an Egg
Float in Salt Water


&nbsp;An egg
sinks to the bottom if you drop it into a glass of ordinary drinking water but
what happens if you add salt? The results are very interesting and can teach
you some fun facts about density.


What you'll
need:


&nbsp;&nbsp;&nbsp;&nbsp; * One egg


&nbsp;&nbsp;&nbsp; * Water


&nbsp;&nbsp;&nbsp; * Salt


&nbsp;&nbsp;&nbsp; * A tall drinking glass




Instructions:


&nbsp;&nbsp;&nbsp; 1. Pour water into the glass until it is
about half full.


&nbsp;&nbsp; 2. Stir in lots of salt (about 6
tablespoons).


&nbsp;&nbsp; 3. Carefully pour in plain water until the
glass is nearly full (be careful to not disturb or mix the salty water with the
plain water).


&nbsp;&nbsp; 4. Gently lower the egg into the water and
watch what happens.



What's
happening?




&nbsp;Salt water
is denser than ordinary tap water, the denser the liquid the easier it is for
an object to float in it. When you lower the egg into the liquid it drops
through the normal tap water until it reaches the salty water, at this point
the water is dense enough for the egg to float. If you were careful when you
added the tap water to the salt water, they will not have mixed, enabling the
egg to amazingly float in the middle of the glass.&nbsp; 



# 3 - Baking Soda
&amp; Vinegar Volcano







Use baking
soda and vinegar to create an awesome chemical reaction! Watch as it rapidly
fizzes over the container and make sure you've got some towels ready to clean
up.





What you'll
need:


&nbsp;&nbsp;&nbsp; * Baking Soda (make sure it's not baking
powder)


&nbsp;&nbsp;&nbsp; * Vinegar


&nbsp;&nbsp;&nbsp; * A container to hold everything and avoid
a big mess!


&nbsp;&nbsp;&nbsp; * Paper towels or a cloth (just in case)




Instructions:





&nbsp;&nbsp; 1. Place some of the baking soda into your
container.


&nbsp;&nbsp; 2. Pour in some of the vinegar


&nbsp;&nbsp; 3. Watch as the reaction takes place!




What's
happening?


&nbsp;The baking
soda (sodium bicarbonate) is a base while the vinegar (acetic acid) is an acid.
When they react together they form carbonic acid which is very unstable, it
instantly breaks apart into water and carbon dioxide, which creates all the
fizzing as it escapes the solution.


For extra
effect you can make a realistic looking volcano. It takes some craft skills but
it will make your vinegar and baking soda eruptions will look even more
impressive!








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