Friday, May 14, 2010

Forms of energy

Potential Energy...[Potential Energy is stored energy due to a body's position or condition]

Chemical potential energy is...

{stored in fuels like petrol and food}

{can be released through chemical reactions}

Gravitational potential energy is...

{the energy an object has as a result of its location or position}

*The object will have more gravitational potential energy when at a higher position with respect to the ground as compared to the energy it possesses at a lower position.

Elastic potential energy is...

{is the energy an object has when being compressed or stretched}

Kinetic Energy... [the energy a body has due to its motion]

*All moving objects have kinetic energy

*e.g. walking person, speeding car, flying bird, rolling ball

Heat Energy... [the energy that flows from a region of higher temperature to a lower one]

* Heat is transferred from a hot to a cold object

*Sun is an important source of heat energy

* e.g. cooking, ironing clothes, melting materials in factories, generating electricity

Light Energy... [the energy that enables us to see]

* Sun is an important source of light energy

* Without light, we would not be able to see a single thing in the world

Sound Energy... [the energy produced when objects vibrate]

* enables us to communicate

* allows us to enjoy music

* e.g. fire alarm, radio

Electrical Energy... [the energy that results from the flow of charged particles]

* almost all electrical appliances make use of electrical energy

* can be transformed into many other forms of energy

* e.g. television, computer

Solar Energy...

{solar panels capture sunlight in the day and the light is transformed into electricity}

Wind Energy...

{wind mills or wind turbines in wind farms make use of the kinetic energy from the wind for generating electricity}

Wave Energy...

{Wave farms use the kinetic energy of waves to generate electricity}

Moments

The principle of moments states that when a body is in equillibrium, the sum of clockwise moments about the pivot/fulcrum is equal to the sum of anti-clockwise moments about the same pivot/fulcrum.

Levers

Levers are basic tools probably used since prehistoric times. They were first described by Archimedes. A lever is a simple machine which makes work easier, which involves moving a load around the pivot or fulcrum using an effort.
Watch this video on levers:
http://www.youtube.com/watch?v=wV1pYkTtsxg


In a first class lever, the fulcrum/pivot is in the center of the load and effort. Some examples are the see-saw, scissors and pliers.




In a second class lever, the load is in the middle of the fulcrum/pivot and the effort. Some examples are staplers, wheelbarrows and nail clippers.


In a third class lever, the effort is between the load and the fulcrum/pivot. Some examples are fishing rods, thongs and tweezers.

Sources:
http://www.istockphoto.com/file_thumbview_approve/6952789/2/istockphoto_6952789-fishing-bear.jpg
http://www.sciencefairprojects-ideas.com/images/stories/seesaw.jpg

Conservation of energy

It is always important to conserve energy because most of the energy we use comes from non-renewable sources, like fossil fuels. They are limited and will run out one day. Some scientists estimated that they will all be used up by the next 200 years. Therefore, it is a must for everyone to conserve energy. The law of conservation of energy states that energy can change from one form to another but it cannot be destroyed or created.

What is Biomass?


Biomass refers to plant and animal material from which oil can be extracted, fermented into gas or burned. Oil palm, jatropha or jojoba are examples of which oil can be extracted to be used for lighting, heating and cosmetics. They can also be turned into biodiesel fuel for vehicles.
A video on Biomass: http://www.youtube.com/watch?v=79nW2o-kYa4
Picture Sources: http://www.infocoreonline.net/computerjunction.in/be1.jpg

Energy


Renewable energy is an energy that comes from natural sources that naturally replenishes, such as, sunlight(solar power), wind(wind farms, wind turbines), rain, tides and geothermal heat(heat stored in the Earth). Non-renewable energy is a natural source that cannot be re-grown, produced or generated and they are used up faster than the Earth can recreate them. It includes fossil fuels like coal, oil and natural gases which will be used up one day so the future generations will not have any of these sources left.

Biomass


Thursday, May 13, 2010

What I have learnt as a summary...
Through the airplane videos, I have learnt about the conservation of energy and why certain airplanes fail in mid-air. Some reasons could be fuel leaks, mistakes by the pilot, bad weather and many other causes.

Friday, May 7, 2010

Formula for...
Density: Mass/Volume
Pressure: Force/Area
Work done: Force(Newtons) x Distance(Metres)= Work done(Joules)
~1ooo Joules= 1kilojoule
~1000 kilojoules= 1 megajoule
~1 kilogram= 10 Newtons
~1 Newton metre= 1 Joule