9.53 am..

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still morning.. can’t test the boat right now.. need to wait until 11.00 a.m to test it..

our Boat ….

 

Propeller..?

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Bagaimanakah hendak menghasilkan propeller yang sesuai dengan bot yang telah direka cipta..? Propeller yang ada di pasaran mempunyai bentuk yang berbeza. Berikut adalah contoh propeller yang dikaji..

Parallel or Series.. ?

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Penyambungan litar dalam pemasangan solar panel sangat penting kerana ia mempengaruhi kuasa yang akan dibekalkan kepada motor. Dalam penyambungan litar, pemasangan secara bersiri atau selari  digunakan. Pemasangan litar secara selari memberikan jumlah kuasa yang lebih besar dibandingkan dengan jumlah kuasa yang diberikan oleh pemasangan litar secara bersiri.

Ekseperimen telah dijalankan untuk menguji litar yang memberikan kuasa yang lebih besar.

Hasil eksperimen, didapati litar selari memberikan kuasa yang lebih besar dibandingkan dengan kuasa yang dibekalkan oleh litar bersiri. Oleh itu, dalam pemasangan solar panel ini, perlu dilakukan pemasangan litar secara selari untuk memaksimumkan kuasa yang akan dibekalkan kepada motor.

Buoyancy Force

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Pengujian daya keapungan telah dijalankan. Tujuan eksperimen ini adalah untuk mengenalpasti bahan utama yang sesuai untuk dibuat boat.

Ekperimen dimulakan dengan menggunakan polisterine (recycle daripada kotak polisterine ink printer)

Polisterine

Seterusnya, menggunakan kertas foam

kertas foam

Seterusnya, menggunakan board foam (skate board)

skate board

Seterusnya, menggunakan tube getah, lidi, polisterine bekas makanan

lidi

paip getah

Semua bahan asas yang dipilih, mempunyai daya keapungan yang tinggi.

Perubahan Jadual

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Minggu peperiksaan pelajar tingkatan 4 telah bermula semalam (09 Mei 2011), oleh itu proses pembuatan boat akan ditunda ke minggu selepas peperiksaan (23 – 27 Mei 2011).

Perbincangan 1

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Tarikh : 04/05/2011

1. REKABENTUK DINAMIK

  • Aerodinamik : bentuk boat mestilah tirus supaya daya aerodinamik dapat dihasilkan. Ini akan menyebabkan boat yang dihasilkan bergerak membelah air dan angin dengan lebih mudah.

Bentuk tirus

  • Eksperimen akan dijalankan untuk mengesahkan ketepatan kenyataan ini.

2. PENYUSUNAN SOLAR PANEL

  • Bersiri : menyusun sel secara bersiri akan menyebabkan motor dapat mengumpulkan voltage yang tinggi.

Litar bersiri

  • Eksperimen akan dijalankan untuk mengesahkan kenyataan ini.

3. PENJANAAN ARUS ELEKTRIK

Penjanaan arus elektrik

PROSES :

  • Solar panel (photovoltaic) : 1 peralatan yang akan menukar sinar cahaya matahari terus kepada tenaga elektrik.
  • Pengumpulan tenaga cahaya oleh solar panel akan maksimum sekiranya solar panel diarahkan 90 darjah ke arah cahaya matahari
  • Tenaga elektrik yang terhasil akan ditukar kepada tenaga kinetik melalui motor yang digunakan. Tenaga kinetik akan menggerakkan motor tersebut dan menyebabkan kipas boat berfungsi. Ini akan menyebabkan boat bergerak
  • Pergerakan boat ke hadapan / belakang dipengaruhi oleh litar yang dihasilkan.

4. PEMILIHAN MATERIAL

  • Prinsip keapungan : bahan yang digunakan untuk menghasilkan boat mestilah bahan yang mempunyai daya keapungan yang tinggi
  • Ini akan menyebabkan boat yang direkacipta boleh terapung di permukaan air

Buoyancy

  • Eksperimen akan dijalankan untuk mengesahkan kenyataan ini.

5. PEMILIHAN KIPAS

  • Rekabentuk kipas (90 darjah) : sesuai untuk dipasang secara mengiring
  • Rekabentuk kipas (sudut belahan angin) : sesuai untuk dipasang secara bersudut

Wings & Flight

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references : MOTION, FORCES AND ENERGY (MC GRAW HILL) NATIONAL GEOGRAPHY

PRODUCING LIFT

Producing lift

According to the Newton’s third law of motion, for every action force there is an equal but opposite reaction force. The wing exerts a downward action force on the air. So the air must exert an upward reaction force on the wing. This reaction force is the lift that enables paper airplanes and jet airlines to fly.

AIRPLANE WINGS

Lift can be increased by increasing the size or surface area of the wing. A larger wing is able to deflect more air downward.

A glider flies at low speeds and uses long wings that have a large surface area to provide the lift it needs

A large cargo plane that carries heavy loads needs large wings to provide a great deal or lift

A plane designed to fly at high speeds, such as a jet fighter, can have small wings

 BIRDS’ WINGS

A bird’s wing provides lift in the same way that an airplane wings does.

A pheasant have short, rounded wings that enable them to take off quickly and make sharp turns

A seabird has long, narrow wings, like the wings of a glider, that help them glide long distances

Falcon, which can fly at high speeds, has small, narrow, tapered wings like those on a jet fighter


Why do objects float?

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references : MOTION, FORCES AND ENERGY (MC GRAW HILL) NATIONAL GEOGRAPHY

THE BUOYANT FORCE

Iceberg

The buoyancy force on egg

Think about the forces that are acting on you as you motionless on the surface of a pool or lake. You are not moving, so according to Newton’s second law of motion, the forces on you must be balanced. Earth’s gravity is pulling you downward, so an upward force must be balancing your weight.

WHAT CAUSES THE BUOYANT FORCE?

The buoyant force

The buoyant force is caused by the pressure that is exerted by a fluid on an object in the fluid. The water exerts pressure everywhere over the surface of the object. Recall that the pressure exerted by a fluid has two properties. One is that the direction of the pressure on a surface is always perpendicular to the surface. The other is that the pressure exerted by a  fluid increases as you go deeper into the fluid.

SINKING AND FLOATING

The fish floats because the buoyant force on it balances its weight. The rock sink because the buoyant force acting on them is not large enough to balance their weight.

The buoyant force pushes an object in a fluid upward, but gravity pulls the object downward. If the weight of the object is greater than the buoyant force, the net force on the object is downward and it sinks. If the buoyant force is equal to the object’s weight, the forces are balanced and the object floats.

CHANGING THE BUOYANT FORCE

When the aluminium is flattened into a thin, curved sheet, the buoyant force is large enough that the sheet floats.

Buoyant force does depend on the shape of the object. The fluid exerts upward pressure on the entire lower surface of the object that is in contact with the fluid. If this surface is made larger, then more upward pressure is exerted on the object and the buoyant force is great.

BOATS

Floats

According to Archimedes’ principle, increasing the weight of the water that is displaced increases the buoyant force.

A few info about the aerodynamic..

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1. SAILFISH (The fastest fish in the ocean)

Sailfish (speed : 110 kph / 68 mph)

The characteristics of the sailfish are as follows :

  • V-shaped prostrusions existing on the sailfish skin in the skin-friction reduction
  • The long bill : a device of reducing drag by separation delay through turbulence generation
  • Large dorsal fin : resembles a sail

2. GREAT BLUE SHARK (Unbony fish)

Great Blue Shark (Speed : 69 kph / 43 mph)

The characteristics of the great blue shark are as follows :

  • Pectoral fins : shark do not have gas-filled swim bladders for buoyancy, but it use the dynamic lift. As these fish swim, their pectoral fin are positioned to create lift which allows the fish to maintain a certain depth

Pectoral Fin for Great Blue Shark

3. FALCON (Fighter jets)

Falcon (Speed : 320 kph / 200 mph)

The characteristics of the falcon are as follows :

  • Long narrow wings : built for speed (pointed wings)
  • Long narrow tails : built for turning capability
  • Slim birds with a small head

4. SWALLOW (The birds of freedom)

Swallow (Swiftness of Flight)

The characteristics of the swallow are as follows :

  • Forked tail & slender body
  • Very short legs with small feet
  • Small bill
  • Long & pointed wings
  • Slender, streamlined bodies with short necks

5. CHEETAH (The fastest land mammal)

Cheetah (Speed : 80 - 100 kph)

The characteristics of the cheetah are as follows :

  • A slender body, a small head, long legs : ideal for speed
  • Without retractable claws : allows the claws to always be exposed (makes for better traction when running)
  • Tail : to help maintain balance at high speeds and during quick turns

Post Mortem Taklimat Solar Boat

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25 April 2011 – 30 April 2011 :

  1. Review 2010 :

BP SOLAR BOAT PRESENTATION :

  • Kurang memuaskan
  • Konsep inovasi dan penyampaian kurang berkesan
  • 2011 : mementingkan konsep pemasaran & inovasi

BP SOLAR BOAT:

  • Kurang inovasi
  • Tiada logo BP dan sekolah
  • Persiapan tidak lengkap
  • Ada kumpulan yg bt hovercraft
  1. Solar Boat Challenge 2011 :

SOLAR BOAT RACE:

  • Guna bahan kitar semula
  • Merupakan hasil reka cipta tersendiri
  • rekacipta yang kukuh, stabil dan sesuai
  • Mengintegrasikan konsep sains dan fungsi aerodinamik dalam rekacipta
  • Mempunyai logo BP, logo sekolah dan guide wire
  • Tidak mempunyai bateri
  • Solar panel boleh diubahsuai kedudukan
  • Propeller : use the recycle materials

PRESENTATION:

  • Masa : 10 minit (persediaan, penyampaian, cleaning)
  • Slide : Abstrak, Objektif, Teori Sains, Reka Bentuk Inovasi, Percubaan & Penambahbaikan)
  • Reka bentuk inovasi (yang telah dicipta)
  • Nilai komersial
  • Pemasaran & pembungkusan produk
  • Font : Universe 45 line / Arial
  • Size font : 12 / 14

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