Friday, March 1, 2013

Science Fact 4-Thermal Expansion

Thermal Expansion is the increase of the objects size by heating.
According to the particle theory, thermal expansion happens because particles have weaker attractive forces when heated so that the expansion occurs.
In daily life, thermal expansion happens because the object is heated until it expands a little bit.
From the 3 states (solid, liquid and gas), gas is the fastest to expand since its particles have very weak attractive forces.
There are 3 types of thermal expansion:(solid)
1.Linear Expansion
2.Area Expansion 
3. Volumetric Expansion

1.Linear Expansion:

-Occurs on 1D (one dimensional) objects such as wires and cables.
-Pattern:
Lt=Lo[1+α*(T-To)]
desc:
Lt= final length of the object  (cm/m)
Lo=initial length of the object (cm/m)
α=coefficient of linear expansion (°c/°k)
T=final temperature (°c/k)    l
To=initial temperature(°c/k) l --- Can be written as  ΔT (delta T)

2.Area Expansion:

-Occurs on 2D objects such as plates
-Pattern:
At=Ao[1+β*(T-To)]
desc:
At=final area of the object (cm2/m2 )     
Ao=initial area of the object(cm2/m2 ) 
β=Coefficient of area expansion (2α)
T=final temperature
To=initial temperature

3.Volumetric Expansion:

-Occurs on 3D objects such as cubes and cuboids
-Pattern:
Vt=Vo[1+ɣ*(T-To)]
Desc:
Vt=final volume of the object (cm/m3)
Vo=initial volume of the object  (cm/m3)
  
ɣ=coefficient of volumetric expansion(3α)
T=final temperature
To=initial temperature

Thermal expansion of liquids:

 -One example is water anomaly
-Water anomaly is the unusual water behavior that first contracts to 0°C, then it expands below to 4°C again. 
-Only happens to water.

The graph of water anomaly.



this is why fish can live in water during winter.


Thermal expansion in gas:


-When you blow a balloon, the gas expands so that the balloon can be big.

Thermal Expansion in daily life:

1.Bimetallic Strip:
From the image, there are 2 metals with different coefficients.
After being heated, they both expand. The one with bigger coefficient will expand faster than the other one.
The bimetallic strip will bend towards the metal with smaller coefficient.

2.Electric Wires:




The electric wires will expand during the day and contract at night. 

This is why we should never set the electric wires too tightly so that they won't break when contracting 
at night.

3.Train Railways:


The train railway is given some gaps so that it won't bend when expanding during the day.



4.Thermometer:
It does regular expansion because of the temperature change. 
We can tell the exact temperature with the thermometer.

Thursday, February 28, 2013

Science Fact 3-Classification

Classification is the grouping of organisms based on their similarity.
Taxonomy is the study of classification.
Taxonomists are people who study classification.

Carlos Linnaeus is called "father of taxonomy" since he classified organisms based on their structure.

There are 7 taxon levels:
Domain
Kingdom
Phyllum (for animal) Divisio (for plants)
Class
Ordo
Family
Genus
Species

1.Domain is divided into eukaryotic and prokaryotic.
Prokaryotic is the organisms that doesn't have nucleus membrane.
(monera kingdom)
Eukaryotic is the organisms that has nucleus membrane.
(fungi, protozoa, animalia & plantae kingdoms)

(a) Monera Kingdom:
-Are unicelluar organisms that doesn't have nucleus membrane.
-Divided into archeabacteria, eubacteria and cyanobacteria.

(b) Protosista/Protozoa Kingdom:
-Most are unicelluar
-Some multicelluar
-Some autotrophic and some heterotrophic
-Aquatic

(c) Fungi:
-Multicelluar, except one, yeast
-Absorptive heterotrophs
-Cell walls made of chitin

(d) Plantae:
-Multicelluar
-Autotrophic
-Absorb sunlight
-Do photosynthesis

(e) Animalia:
-Multicelluar
-Heterotrophs
-Feed on animals and plants




Science Fact 2 - Changes of State

There are 3 types of states of matter: Solid, Liquid and Gas.
Things can change its state because of the temperature change.
The process of changing of state are in this picture below:
The processes melting, evaporation and sublimation gains heat or needs heat
The processes freezing, condensation and resublimation/deposition releases heat

1.Melting:
Process from solid to liquid.
example:
ice melting, chocolate melting, butter melting.
2.Freezing:
Process from liquid to solid
example:
ice in the freezer, making ice cream.
3.Evaporation:
Process from liquid to gas.
example:
drying clothes, opened methanol bottle.
4.Condensation:
Process from gas to liquid.
example:
steam of boiling water, water on the cold glass's surface, morning dew on the leaf.
5.Sublimation:
Process from solid directly to gas.
example:
camper in the wardrobe, dried ice.
6.Resublimation/Deposition:
Process from gas directly to solid.
example:
dried ice, snow.


Wednesday, February 27, 2013

Science Fact 1- Energy

Energy is something that can't be destroyed or created. It comes from the sun (solar energy).
or from radioactive atoms in Earth's interior. Through this, we are able to produce different kinds of energy and this allows machines and even living things to move and to do things. 
Sun is the main source of energy on Earth. 
Without even knowing, we use a lot of energy to do our activities such as washing the clothes, flying the kites, cooking food, playing video games, etc. The sun produces many kinds of energy : Heat energy, so the earth will be warm; Light energy, so the earth will be bright; solar energy, through solar cells, so there will be electricity.
On Earth, there is called "alternative energy" which means that energy which will never finish when we waste it. These are alternative energies:
Sun, water, air and biofuel energy.
Others are like heat energy, light energy, potential energy, kinetic energy, water energy, magnetic energy, muscle energy, etc.
Blog viewers, energy is everywhere around you. You need energy to do your activities, even though it's only a bit.
Question of the fact 1:
What happens without energy on Earth?

Leave your answers in comments!



Science

Hey, blog readers! Science can be the nature or social. But I would like to decide this blog website is the information of nature one. This can have physics, biology and even chemistry.
You'll be able to become a professor later if you read this and understand it. Nature Science is all about what you can learn about the things around you like animals, energy, plants, human anatomy, etc. Feel free to ask in comments! Enjoy reading ;D