Form 2 Scientist : Water and Solution

Water and Solution Part 1

Physical Characteristic of Water

• Water is the only substance that can exist in three form: solid (ice), liquid (water) and gas (steam)

• Waters are odorless, colorless and tasteless
• Waters are neutral
• The presence of water can be detected when a blue cobalt chloride paper changes to pink
• The freezing point of water is 0' Celsius
• The boiling point of water is 100' Celsius

Composition of Water

• Water is a compound
• Water is made up of 2 hydrogen atom and 1 oxygen atom
• These atom bound to each other to form a 'V' shape 
• The formula of water is H2O
• Hydrogen and oxygen in the water can be separated through a process known as Electrolysis

• The diagram above shows the process of electrolysis
• Cathode and Anode is a pair of electrodes that are connected to batteries.
• Cathode is connected to negative terminal while Anode is connected to positive terminal of the battery
• Hydrogen gas is released at the cathode end while oxygen gas is released at the anode end
• The volume of hydrogen collected is twice the volume of oxygen gas
• The volume ratio of hydrogen to oxygen is 2:1

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What Is Science 

Science is the systematic study of nature to understand the natural phenomenon and how it affects our lives and the environment. Science is a knowledge that is important to improve human life. With the growth of science, we can communicate with people in different continent via the internet. Many diseases can be cured and surgery can be done by the surgeon. All the progresses are the results of exploration of science by the scientist.

The exploration of science by the scientist is done in order to solve problems, to invent and discover new things to help people. As human, we always have questions of our environment and we tend to find the answer to the questions. Science is continuously expanding. But, science still has its limits. That is why there are still some diseases that are not curable yet. Hurricanes or tsunami still do happen and they are unpreventable.

Use And Benefits of Science

Science is important for us in order to understand ourselves and our surrounding. In human lives, science is important to make our lives more comfortable. With science, we have improved our standard of living continuously. All these things happen because science contributes to new discoveries, inventions and knowledge.

The new discoveries and the knowledge gained, are applied as technology. Technology is the practical use of science to satisfy human needs. Science is important to help us to:

• solve problems.
  • Science has helped us to get electrical energy from energy of sunlight by the creation of solar panels.
• speed things up.
  • Transports are created in order to transport people and goods. Transport can help us to travel through water, land and space.
• ease our work.
  • Machine are created to make things easier. For example, tractor is built to help the farmer to harvest paddy faster.
• enjoy our leisure.
  • The example of contribution that help us to enjoy our leisure are the invention of television and computers.
• ease of communication.
• Telephones, computers, and satellites are invented to help us communicate easier and faster.

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Segi Tiga Bermuda (Bermuda Triangle)

1. Merujuk sempadan berbentuk tiga segi di barat laut Lautan Atlantik meliputi Kepulauan Bermuda, Selat Florida dan Laut Caribbean.
2. Kedudukannya lebih kurang di latitud 20 hingga 40 darjah utara serta longtitud 55 hingga 85 darjah barat merangkumi kawasan seluas empat juta kilometer persegi.
3. Mengikut laporan pihak marin Amerika pada tahun 1973, sejak 100 tahun ini telah berlaku lebih kurang 8000 kes kemalangan termasuk kehilangan 50 kapal serta 20 kapal terbang di kawasan ini.

Teori di Sebalik Segi Tiga Bermuda 

1.  Hidrat Mentana : Hidrat mentana yang keras di bawah laut akan pecah apabila berlaku gempa bumi dan mengeluarkan banyak banyak gas mentana. Apabila ini berlaku, banyak buih akan terbentuk. Buih ini boleh mempengaruhi ketumpatan air serta melemahkan daya apung kapal. Kapal akan ditarik ke bawah lalu tenggelam. Hidrat mentana juga mengubah keadaan atmosfera lalu mengakibatkan kerosakan teruk kepada kapal tebang.
2. Perubahan medan magnetik bumi : Secara umumnya, penuruan medan magnetik bumi berlaku setiap 200 ke 250 ribu tahun semasa ia mengubah haluan. Perubahan medan magnetik yang berlaku secara tiba-tiba boleh mengakibatkan kerosakan pada kapal dan kapal terbang. Segi tiga bermuda terletak di atas medan magnetik kurang stabil lalu mengakibatkan berlakunya pelbagai fenomena. Selain itu, ada pelbagai tanggapan seperti kemunculan makhluk asing dan kewujudan dimensi lain. 

Form 2 Scientist : Sensory Organs Part 3

The Sense of Hearing

Structure of the Human Ear

1. The ear is the sensory organs of hearing and balance.
2. The sense of hearing is sensitive to sound stimuli.
3. The human ear can be divided into three main parts : the outer ear, the middle ear and the inner ear.
4. The figure below shows the cross section of the human ear.

• Pinna - collects and directs sound waves (vibrating air) into the auditory canal.
• Auditory canal - directs sound waves to the eardrum
• Eardrum - vibrates at the same frequency as the sound waves that hit it and transfer the vibrations to the ossicles
• Ossicles - amplify the vibrations and transfer them from the eardrum to the oval window
• Oval Window - transfer the vibrations from the ossicles to the inner ear
• Round Window - vibrates in opposition to the oval window lying above it
• Semicircular canals - help the body maintains its balance (not involved in the mechanism of hearing)
• Eustachian tube - helps the balance the air pressure on both sides of the eardrum (not involved in the hearing mechanism).

The hearing mechanism 

The pinna gathers sound waves and directs them to the auditory canal

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The sound waves travel along the auditory canal and reach the eardrum. It vibrates at the same 

frequency as the sound waves.

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The vibrations are transferred to the ossicles. The ossicles amplify the vibrations 20 times

in magnitude before passing them to the oval window.

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Vibrations of the oval window cause the fluid in the cochlea to vibrate.

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The movement of the fluid stimulates the receptors in the cochlea.

Nerve impulse are generated.

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The auditory nerve sends the nerve impulse to the brain.

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The brain interprets the messages as sounds. 

Form 2 Scientist : Sensory Organs Part 2

1.3 The Sense of Smell

Structure of The Nose

1. The nose is the sensory organs for smell.
2. The upper part of the nasal cavity  of the nose has many sensory cells or receptors to detect smell.
3. These smell receptors are sensitive to all kinds of smells.

Detection of Smells

1. Certain chemicals particles present in the air circulate the smells in the air. For example flowers, food and perfume release chemicals into the air.
2. When these chemicals particles enter the nasal cavity, they dissolves in the mucus lining that coats the smell receptors in the nasal cavity.
3. The dissolved chemicals particles stimulate the smell receptors.
4. The smell receptors then send out nerve impulse to the brain. The brain identities the smell.
5. When a person has a cold, he is unable to detect smells well. This is because too much mucus is being produced. The mucus prevents the chemicals from stimulating the smell receptors. 
6. Structural adaptions of the nose to detect smells:           

• Smell receptors are located at the roof of the nasal cavity. This enables the receptors to have maximum exposure to the air that enter the nasal cavity. 
• The smell receptors are always covered in moist mucus which is secreted by the glands in the nasal cavity.
• Figure 1.6 shows how smell are detectedChemicals in the air.

(a) Chemicals enter the nasal cavity and are dissolved in the mucus lining. Upon dissolving, they stimulate the smell receptors.
(b) Messages are sent to the brain along the nerves.
(c) The brain interprets the messages.
(d) Smells are identified.

Figure 1.7 Structure of the nose

1.4 The Sense of Taste 

1. The tongue is the sensory organs that gives us the sense of taste. It is sensitive to sweet, salty,sour, and bitter taste.
2. The upper surface of the tongue is rough. This is because it is covered with taste buds.
3. Taste receptors can be found in the taste buds. They responds to various chemicals in food. Each type of taste receptors is sensitive to a certain type of taste.
4. The tongue has four types of taste receptors.
5. These are ; sweet receptors, sour receptors, salty receptors and bitter receptors.
6. Each receptor is located in a particular area of the tongue. Thus, each area of the tongue able to detect a certain type of taste.
7. Figure 1.8 shows the location of the various taste receptors.

Sense of Taste and Smell

1. Both the sense of taste and smell are needed to detect the flavors of food accurately.
2. The nasal cavity and the mouth are connected.
3. Chemicals from food that stimulated the taste receptors also move into our nasal passages. These chemicals stimulated the sensory cells in the nose.
4. If a person has a cold or closes his nose, the air passages in the nose are blocked. This reduces the sensitivity of the smell receptors. Food becomes less tasty or different from its original taste. This is because the sense of taste and smell are closely related