http://www.youtube.com/watch?v=YOjD6bs7BXk

Heat energy

Heat energy is in volcanoes and ice

Most of us use the word ‘heat’ to mean something that feels warm, but science defines heat as the flow of energy from a warm object to a cooler object.
Actually, heat energy is all around us – in volcanoes, in icebergs and in your body. All matter contains heat energy.
Heat energy is the result of the movement of tiny particles called atoms, molecules or ions in solids, liquids and gases. Heat energy can be transferred from one object to another, and the transfer or flow due to the difference in temperature between the two objects is called heat.
For example, an ice cube has heat energy and so does a glass of lemonade. If you put the ice in the lemonade, the lemonade (which is warmer) will transfer some of its heat energy to the ice. In other words, it will heat up the ice. Eventually, the ice will melt and the lemonade and water from the ice will be the same temperature. This is known as reaching a state of thermal equilibrium.

Moving particles

Matter is all around you. It is everything in the universe – anything that has both mass and volume and takes up space is matter. Matter exists in different physical forms – solids, liquids and gases.
All matter is made of tiny particles called atoms, molecules and ions. These tiny particles are always in motion – either bumping into each other or vibrating back and forth. It is the motion of particles that creates a form of energy called heat (or thermal) energy that is present in all matter.

Particles in collision

The particles in solids are tightly packed and can only vibrate. The particles in liquids also vibrate but are able to move around by rolling over each other and sliding around. In gases, the particles move freely with rapid, random motion.

Transferring heat energy – particles in collision

At higher temperatures, particles have more energy. Some of this energy can be transmitted to other particles that are at a lower temperature. For example, in the gas state, when a fast moving particle collides with a slower moving particle, it transfers some of its energy to the slower moving particle, increasing the speed of that particle.
With billions of moving particles colliding into each other, an area of high energy will slowly transfer across the material until thermal equilibrium is reached (the temperature is the same across the material).

Changing states by heat transfer

Faster moving particles ‘excite’ nearby particles. If heated sufficiently, the movement of particles in a solid increases and overcomes the bonds that hold the particles together. The substance changes its state from a solid to a liquid. If the movement of the particles increases further in the liquid, then a stage is reached where the substance changes into a gas.

Three ways of transferring heat energy

All heat energy, including heat generated by fire, is transferred in different ways:	Convection Conduction Radiation
Convection transfers heat energy through the air (and liquids). As the air heats up, the particles move further apart and become less dense, which causes the air to rise. Cooler air below moves in and heats up, creating a circular motion. The warm air circles and heats the room.
Conduction transfers heat energy through one substance to another when they are in direct contact. The moving molecules of a warm material can increase the energy of the molecules in a cooler material. Since particles are closer together, solids conduct heat better than liquids or gases.
Radiation is the heat that we feel coming from a hot object. It warms the air using heat waves (infrared waves) that radiate out from the hot object in all directions until it is absorbed by other objects. Transfer of heat by radiation travels at the speed of light and goes great distances. With a log fire, the air in the room above the fire is heated and rises to create convection currents. The heat felt directly from the fire is transmitted to us through radiation. Conduction helps to keep a fire going by transferring heat energy directly from the wood to neighbouring wood in the fire

An effect of heat – expansion

When gases, liquids and solids are heated, they expand. As they cool, they contract or get smaller. The expansion of the gases and liquids is because the particles are moving around very fast when they are heated and are able to move further apart so they take up more room. If the gas or liquid is heated in a closed container, the particles collide with the sides of the container, and this causes pressure. The greater the number of collisions, the greater the pressure.
Sometimes when a house is on fire, the windows will explode outwards. This is because the air in the house has been heated and the excited molecules are moving at high speed around the room. They are pushing against the walls, ceiling, floor and windows. Because the windows are the weakest part of the house structure, they break and burst open, releasing the increased pressure.

Posted by  Noraidah@Idah Selimin(CT10210531)

WHAT IS HEAT ?

The Universe is made up of matter and energy. Matter is made up of atoms and molecules (groupings of atoms) and energy causes the atoms and molecules to always be in motion - either bumping into each other or vibrating back and forth. The motion of atoms and molecules creates a form of energy called heat or thermal energy which is present in all matter. Even in the coldest voids of space, matter still has a very small but still measurable amount of heat energy.

Energy can take on many forms and can change from one form to another. Many different types of energy can be converted into heat energy. Light, electrical, mechanical, chemical, nuclear, sound and thermal energy itself can each cause a substance to heat up by increasing the speed of its molecules. So, put energy into a system and it heats up, take energy away and it cools. For example, when we are cold, we can jump up and down to get warmer.

Here are just a few examples of various types of energy being converted into thermal energy (heat).

(1) Mechanical energy is converted into thermal energy whenever you bounce a ball. Each time the ball hits the ground, some of the energy of the ball's motion is converted into heating up the ball, causing it to slow down at each bounce.

A thermal infrared image of a ball before (left) and after (right) being bounced.

(2) Thermal energy can be transfered to other objects causing them to heat up. When you heat up a pan of water, the heat from the stove causes the molecules in the pan to vibrate faster causing the pan to heat up. The heat from the pan causes water molecules to move faster and heat up. So, when you heat something up, you are just making its molecules move faster.

(3) Electrical energy is converted into thermal energy when you use objects such as heating pads, electrical stove elements, toasters, hair dryers, or light bulbs.

A thermal infrared image of a hair dryer and a flourescent light bulb.

(4) Chemical energy from the foods we eat is converted into heating our bodies.

(5) Light from the sun is converted to heat as the sun's rays warm the earth's surface.

(6) Energy from friction creates heat. For example when you rub your hands, sharpen a pencil, make a skid mark with your bike, or use the brakes on your car, friction generates heat.

A thermal infrared image of a pencil after being sharpened (left) and of hot brakes in a car (right). Notice the hot tip of the pencil.

There are many other examples. Can you think of some more?

The more energy that goes into a system, the more active its molecules are. The faster molecules move, the more heat or thermal energy they create. So, the amount of heat a substance has is determined by how fast its molecules are moving, which in turn depends on how much energy is put into it.

ACTIVITY: Let students pretend to be molecules. First have them stand still and close together. Then have the students wiggle and then walk and move around to demonstrate more energy entering the system. Have them move faster and jump up and down as even more energy enters the system. Then have the students stop and notice where they are. They should be much farther apart and should feel much warmer than they were originally.

Although molecules are too small to see, we can detect and measure their movement.

EXPERIMENT: To do this experiment you will need 2 clear bowls and food color. Fill one clear bowl with hot water and another with the same amount of cold water. When the water is still, put a drop of food color into the center of each bowl. As the water molecules bump into the food color molecules, the food color will move around. Since the hot water molecules are moving faster, they will bump into the food color harder and more frequently causing it to spread more quickly than the food color in the cold water.

Summary: Heat is the energy an object has because of the movement of its atoms and molecules which are continuously jiggling and moving around, hitting each other and other objects. When we add energy to an object, its atoms and molecules move faster increasing its energy of motion or heat. Even objects which are very cold have some heat energy because their atoms are still moving. 

 Posted by Ling Pick Ha (CT10210397)

TAJUK: TENAGA HABA

KONSEP FIZIK	KEMAHIRAN SAINTIFIK	AKTIVITI SAINTIFIK	MASA (MINGGU)
1. TERMOMETRI 1.1 Haba 1.2 Suhu 1.3 Keseimbangan terma 1.4 Termometer	Menakrifkan termometri. Membeza antara haba dan suhu. Menakrif keseimbangan terma dan contoh sistem. Menerangkan struktur binaan dan prinsip kerja beberapa jenis termometer utama.	·  Mengaitkan keseimbangan terma dengan prinsip kerja termometer merkuri. ·  Demonstrasi kaedah penentukuran skala termometer merkuri. ·  Menyelesaikan masalah melibatkan penentukuran skala termometer.	1
2. MUATAN HABA TENTU 2.1 H = mcq 2.2 H = Pt 2.3 H = Vit	Menakrif muatan haba tentu dan unitnya.. Menakrif tenaga elektrik. Menentukan andaian bagi perubahan tenaga elektrik kepada tenaga haba	·  AMALI menentukan muatan haba tentu pepejal (Aluminium). ·  AMALI menentukan muatan haba tentu cecair (air). ·  Menyelesaikan masalah melibatkan pengiraan muatan haba tentu. ·  Mengkaji kepentingan muatan haba tentu dalam kehidupan.	1.5
3. HABA PENDAM TENTU 3.1 H = mL 3.2 H = Pt 3.3 H = Vit	Menakrif haba pendam tentu dan unit nya. Membeza antara muatan haba tentu dan haba pendam tentu. Membeza antara haba pendam tentu pelakuran dan haba pendam tentu pengewapan.	·  AMALI menentukan haba pendam tentu pelakuran ais. ·  AMALI menentukan haba pendam tentu pengewapan air. ·  Menyelesaikan masalah melibatkan pengiraan haba pendam tentu. ·  Menyelesaikan masalah menentukan jumlah kuantiti haba diperlukan untuk menukar ais menjadi wap. ·  Melukis graf penyejukan atau pemanasan	1.5
4. PENDIDIHAN DAN SEJATAN 4.1 Pendidihan 4.2 Penyejatan 4.3 Penyejukan oleh sejatan.	Membeza antara pendidihan dan sejatan. Menyatakan faktor-faktor mempengaruhi kadar didihan dan kadar sejatan. Mengaplikasi pendidihan dan penyejatan dalam kehidupan. Menerangkan konsep penyejukan oleh sejatan.	·  AMALI mengkaji faktor-faktor mempengaruhi kadar sejatan dan pendidihan. ·  Demonstrasi menunjukkan kesan penyejukan oleh penyejatan. ·  Menulis esei struktur binaandan prinsip kerja penyaman udara dan peti sejuk. ·  Menyelesaikan masalah berkaitan sejatan dan pendidihan dan kaitannya dengan teori kinetik jirim.	1.5
5. ENJIN HABA 5.1 Enjin empat lejang jenis petrol 5.2 Enjin empat lejang jenis diesel	Menakrif enjin empat lejang. Membeza antara enjin petrol dan enjin diesel.	·  Menghurai secara ringkas struktur binaan dan prisip kerja enjin empat lejang petrol dan diesel. ·  Menjadualkan perbezaan antara enjin petrol dan enjin diesel.	1

Posted by Jomilin Sibin   (CT10210320)

Haba Tahun 5

http://www.tutor.com.my/tutor/arkib2002.asp?e=UPSR&s=SCI&b=OKT&m=3&r=m&i=NOTA

PERUBAHAN BENTUK – BENTUK TENAGA (‘Transformation of Energy’)

Tenaga tidak boleh dicipta atau dimusnahkan.
(‘Energy Is Neither Created Nor Destroyed.’)

Apabila kita menggunakan tenaga, ia tidak hilang. Kita menukarkan ia dari satu bentuk ke bentuk yang lain.
(‘When we use energy, it doesn't disappear. We change it from one form of energy into another.’)

Tenaga bertukar bentuk atau mengalami transformasi bentuk, tetapi jumlah tenaga di dalam alam semesta tidak berubah.
(‘Energy changes form or we can say energy can be transformed, but the total amount of energy in the universe stays the same.’)

Dalam aktiviti harian, pertukaran tenaga dari satu bentuk ke bentuk yang lain akan melibatkan kehilangan tenaga. Sebahagian daripada tenaga hilang sebagai tenaga haba.
(‘In reality, converting one form of energy into another form always involves a loss of useable energy. The rest of the energy is lost as heat.’)

Perubahan tenaga ini melibatkan satu hukum fizik yang dikenali sebagai Hukum Termodinamik. Untuk maklumat lanjut sila klik di sini.
(‘The transformation of energy involves a law of physics that we called the Law of Thermodynamics. Click here for more informations.’)

Contoh – contoh perubahan tenaga.
(‘Examples of Transformation of Energy’)

Dalam setiap contoh yang diberi, tenaga bermula dengan satu bentuk dan bertukar kepada bentuk yang lain. Namun terdapat juga tenaga bertukar kepada lebih daripada satu bentuk sebelum terhasil bentuk tenaga paling akhir.
(‘In each example energy starts as one form and changes into another form. In some cases the energy might actually change into more than one form before the final energy out.’)

Aktiviti – aktiviti yang terlibat dengan perubahan tenaga.
(‘Activities involve of transformation of energy.’)

a) Menghidupkan lampu : Tenaga elektrik → tenaga cahaya
(‘Switching on the lights : Electrical energy → light energy.’)

Posted by  Yea Lea Nah(CT10210827)

Heat energy

Berikut adalah video tentang pengaliran haba.

Posted by Saimen lutas  (CT10210686)