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3 Νοε 2013 (πριν από 3 χρόνια και 7 μήνες)

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Final Project

1. Problem Statement


How Do Clouds Form?


2. Background


The cloud means to stay in the atmosphere on the water droplets or ice crystals
colloidal

aggregates.

The cloud is the tangible result of the huge water cycle on Earth.

Th
e sun shines on the Earth's surface, the water evaporates the formation of water
vapor, water vapor over saturated, water molecules will gather dust in the air
(condensation nuclei) around, the resulting water droplets or ice crystals scatter
sunlight in a
ll directions, which on the appearance of the cloud. White cloud reflection
and scattering of electromagnetic waves of all bands, so clouds the color of gray color,
the clouds thin, but when they become too thick or dense that sunlight can not pass,
they c
an look gray or black the. Other planets in the cloud will not necessarily be
composed of water, such as sulfuric acid clouds of Venus.


Folk have long recognized that to predict weather changes by the concept of cloud. In
1802, English naturalist Luke How
ard proposed a classification of the famous cloud,
so that a more accurate view of the cloud measured weather. Howard will be divided
into three categories: cumulus, stratus and cirrus clouds. These three cloud coupled
to said high level of words and words

said rainfall, resulting in ten kinds of basic types
of clouds. According to these cloud phase, people grasp the experience of some of
the more reliable forecast the next 12 hours, changes in the weather. Fluffy cumulus
clouds, for example: if the distrib
ution is very dispersed, can be expressed as the
good weather, but if the clouds to expand or new development, it means that will

dump heavy rain.




3.

Hypothesis


Why i
s it that on a cold day we can see our breath? The answer is that the air we
breathe out contains moisture in the form of water vapor. When that warm, moist air
meets the cold, dry air outside, a cloud forms.


4.

Procedure


Materials :

·
large wide
-
mouthed j
ar

·
latex gloves

·
matches

·
water


Experimental :



First, you will need to learn how to make a cloud chamber using the jar, glove,

match, and water.



Barely cover the bottom of the jar with water.



Hang the glove inside the jar with
its fingers pointing down, and stretch the
glove's open end over the mouth of the jar to seal it.



Insert your hand into the glove and quickly pull it outward without disturbing the
jar's seal. Nothing will happen.



Next, remove the glove, drop a lit match i
nto the jar, and replace the glove. The
match will go out and create smoke particles in the jar which will become
nucleation sites.



Pull outward on the glove once more. Fog forms inside the jar when you pull the
glove outward and disappears when the glove
snaps back. The fog will form for 5
to 10 minutes before the smoke particles settle and have to be replenished.



Now that you know how to make a cloud in a jar, you can experiment with
different conditions that lead to cloud formation. You can change severa
l things in
your experiments, including:













5.

Results


Trial

Glove

Match

Water

Cloud (No, Yes)

1

Inside

No

Yes

No

2

Inside

Yes

No

No

3

Inside

Yes

Yes

Yes

4

Outside

No

Yes

No

5

Outside

Yes

No

No

6

Outside

Yes

Yes

Yes





6.

Conclusions


Variable

How to change it:

air pressure

to increase
-

start the glove on the outside and push it into the jar

to decrease
-

start the glove on the inside and pull it out of the jar

nucleation

more

nucleation
-

drop more lit matches into the jar

less nucleation
-

drop fewer lit matches into the jar

temperature

to increase
-

place the jar in a pot of hot water

to decrease
-

place the jar in a tray of ice

humidity

to increase
-

add more water
to the jar

to decrease
-

add less water to the jar

The
re must be three main ingredients present in order for clouds to form :


Moisture
-

There must be sufficient water vapor in the air to build a cloud.

Cooling air
-

The air temperature must decrease enough for water vapor to condense.

Condensation nuclei
-

Tiny particles, invisible to the human eye, such as dust, dirt,
and pollutants, provide surfaces on which water molecules can gather and condense
into water droplets.


If the conditions are right, then a cloud will form. Clouds often form where two weathe
r
fronts meet, like when a cold front meets a warm front.