What Is The Best Design For A Cannon?

A cannon is a piece of artillery that will use an explosive-based propellant or gunpowder to launch a projectile. Each cannon is different in range, mobility, rate of fire, angle of fire, and fire power. The original definition of the word cannon can be translated as tube, cane, or reed. (1)

The first cannon was used in China, and was considered to be unsafe and was smaller in size.  Quality was problematic and the cannon would burst with great frequency.

The cannon began to improve around mid-century. The casting was made of a mixture of tin and bronze. However, bronze was so much more expensive than iron and the problem of safety remained. (2)

Over time, the price tended to fall as technology and experience improved. The cannon got much better and soon after, gunpowder was produced.

The cannon transformed naval warfare in the early modern period. As rifling became more common, the accuracy and destructive power of the cannon was significantly increased, and they became deadlier than ever. (2)

The modern day cannon is similar to those used in the Second World War, although the importance of larger machinery has declined with the development of the missile. (1) However, at the same time, it is more commonly used now since it is attached to the army tank.

A cannonball has to be spherical. Otherwise, they would tumble uncontrollably due to air resistance, and tend to arrange the long axis of the projectile perpendicular to the direction of projection, giving maximum drag. (1)

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Projectile motion is when an object is fired at some initial velocity or dropped and is moved under the influence of gravity.

The most important thing to remember about projectile motion is that the effect of gravity is independent on the horizontal motion of the object. (3)

The best angle to have in order to get a large horizontal distance is 45. It's only the best trajectory if you have a launcher that has a fixed launch velocity regardless of launch angle and your projectile has no lift and you are interested in getting the maximum horizontal displacement on a level plane. (3)

(1) Cannon. (n.d.). Retrieved from http://www.hyw.com/books/history/cannon.htm

(2) Calvert, J. B. (2009, September 04). Cannon. Retrieved from http://mysite.du.edu/~jcalvert/tech/cannon.htm

(3) Projectile motion. (n.d.). Retrieved from http://www.splung.com/content/sid/2/page/projectiles

Gizmos: Golf Range - Assessment Results

Early History Of Flight

1485 - Leonardo Da Vinci: The Ornithopter And The Study Of Flight

Leonardo Da Vinci was probably the first person that conducted a true study of flight in the 1480's. (1) He explained his theory on the relationship between mechanical flight and a bird by illustrating the wing and the tail of a bird and the possibility that man could fly.

He designed a mechanical device called the ornithopter that closely resembled the structure of the bird. The ornithopter flying machine was never actually created. (1) It was a design that Leonardo Da Vinci created to show how man could fly. The modern day helicopter is based on this concept.

1783: The Montgolfier Hot Air Balloon

 The Montgolfier hot air balloon was the first balloon to be made and fly in the air. They used the smoke from a fire to blow hot air into a silk bag. The silk bag was attached to a basket. The hot air then rose and allowed the balloon to be lighter than air. (2)

In 1783, they put a sheep, rooster, and a duck in a colourful balloon and it climbed to a height of about six thousand feet and travelled more than one mile.

1799 - 1850's: George Cayley – Glider

Sir George Cayley experimented with wing design, distinguished between lift and drag, formulated the concept on the vertical tail surface, the steering rudder, the rear elevator, and the air screw. Cayley worked to discover a way that man could fly. Cayley designed how a glider can be used to control the movement of the body. (3)

For a long period of time, Cayley tried to improve his glider. He changed the shape of the wing so that the air would flow over them correctly. He also designed a tail to help with the stability. He tried a biplane design to add strength to the glider. (3) Cayley recognized that there would be a need for machine power if the flight was to be in the air for a long time.

He concluded that a fixed wing aircraft with a power system for propulsion and a tail to assist in the control of the airplane, would be the best way to allow man to fly.

1903 - First Flight

Orville and Wilbur Wright spent much of their life learning about each and every inventor that contributed to flight. They learned about how the wind would help with the flight and how it would affect the mechanical device once up in the air. They designed and used a wind tunnel to test the shape of a glider's wing and tail. After finding a shape that consistently would fly, they turned their attention to how to create a propulsion system that would create the lift needed to fly.

The "Flyer" lifted from level ground to the north of Big Kill Devil Hill on December 17, 1903. The first heavier than air flight traveled one hundred and twenty feet. (4)

Humankind was now able to fly. During the next century, each and every mechanical device we use today was developed to carry anything up in the air.

Bibliography

(1) Bellis, M. (n.d.). Leonardo Da Vinci The Artist And Leonardo Da Vinci The Inventor. Retrieved from http://inventors.about.com/od/italianinventors/a/LeonardoDaVinci.htm

(2) Bellis, M. (n.d.). History Of Balloons - Montgolfier Balloon. Retrieved from http://inventors.about.com/od/astartinventions/ss/airship_2.htm

(3) Early History Of Flight - Kites - Hot Air Balloons - Early Gliders. (n.d.). Retrieved from http://inventors.about.com/library/inventors/blearlyflight.htm

(4) Bellis, M. (n.d.). The Wright Brothers - First Flight Of An Airplane. Retrieved from http://inventors.about.com/od/wstartinventors/a/TheWrightBrother.htm

Right Hand Rule Number 2

Here Is A Summary Of Right Hand Rule Number 2 For Conventional Current Flow:

- Grasp the coiled conductor with the right hand such that curved fingers point in the direction of conventional, or positive, current flow.
- The thumb points in the direction of the magnetic field within the coil.
- Outside the coil, the thumb represents the north end of the electromagnet produced by the coil.

The second right hand rule predicts the relationship between the direction of conventional current flow in a coil and the direction of the magnetic field at the end of the electromagnet.

Creation Of Magnetic Fields Around Current-Carrying Conductors

(Difference Between Right Hand Rule Number One And Right Hand Rule Number Two)

Right Hand Rule Number One

Current Forced Through Conductor -> Straight Line Conductor -> Straight Thumb Along Conductor -> Fingers Show Circular (Curved) Magnetic Field Lines

Right Hand Rule Number Two

Current Forced Through Conductor -> Coiled Conductor -> Curved Fingers Around Conductor -> Thumb Shows Straight Magnetic Field Lines (At Coil Ends)

EARTH AS A MAGNET

For my whole life I assumed that the north pole was called the north pole because when looking at the map, the needle pointing north is facing in the direction of the north pole. I never questioned if this was the truth or not, I just went along with it like a foolish young child. However, on Thursday, February 23, 2012, the truth was exposed to my innocent mind.

First, let's think of the earth as being a magnet or having a magnet buried inside. (1) In the centre, the core is made out of iron, and as it moves, it creates an electric current that causes a magnetic field around the earth. A compass needle is actually a tiny magnet, with the north end painted red. In order for the north end of the compass to point to the North Pole, you have to assume that the "magnet" in earth has to have the south end at the North Pole. So in actuality, the North Pole is the South Pole! It is called the North Pole because it is near the top of the earth, or geographic north, however, it is really a magnetic "south" pole. This is why a compass needle's north end points to it. 

This is due to the fact that opposite charges attract each other. Therefore, that would cause the north end of the compass needle to point toward the south end of the buried magnet. So the compass would point towards the North Pole. However, these poles are not quite lined up with the geographic North Pole and South Pole shown on a map, because the moving inner core's poles are constantly wandering around. 

In reality, the bar magnet does not run exactly the earth's rotational axis. It is slightly bent to the side. Using a compass in the north can give you problems. The needle is actually pointing at the magnetic pole, which is not directly at the geographic pole. Now, in general most people use a GPS to determine their desired location, which does not rely on the position of "true north" but rather on satellites.

It is only at the equator that the field is parallel to the earth's surface. The angle between the earth's surface and the magnetic field is called the angle of inclination. 

Earth's magnetic field lines also attract particles from outer space. As particles stream down through the atmosphere towards the magnetic poles, they cause the northern lights. (3) 

(1) Earth's Magnetic Field. (n.d.). Retrieved from http://adventure.howstuffworks.com/outdoor-activities/hiking/compass1.htm

(2) Earth's Inconstant Magnetic Field. (2003, December 29). Retrieved from http://science.nasa.gov/science-news/science-at-nasa/2003/29dec_magneticfield/

(3) How Does The Aurora Borealis (The Northern Lights) Work?. (n.d.). Retrieved from http://science.howstuffworks.com/nature/climate-weather/atmospheric/question471.htm

The Energy Ball Report

The Energy Ball Report

Energy Ball (7)

When the electrode on each side of the ball is touched, the ball will flash and make a humming sound. More than one person can make this energy ball work as long as everyone is in some way touching the person beside him or her. Through this experiment, we understand the importance, as well as the difference between a series and parallel circuit.

When there is more than one electrical device present in a circuit with an energy source such as a battery, they can either by connected in series or in parallel. 

Series Circuit

A Series Circuit (8)

A Series Circuit With A Broken Light Bulb (8)

In a series circuit, each device is connected in a way that there is only one path which the charge can pass through. Each charge passing through will therefore pass through each resistor. By adding an extra resistor each time, the overall current will decrease in the circuit, and will result in more overall resistance. (1) Also, if a resistor is removed, the every other resistor will no longer continue to work. If the current is cut from one resistor, it is cut from the rest of them as well. The charge flowing through the circuit is at the same rate all around. The current is no greater at one location as it is at another location. The charge does not pile up and begin to accumulate at any given location such that the current at one location is greater than another location. The actual amount of current is based on the amount of overall resistance. There is a definite relationship between the resistance of the individual resistor and the overall resistance. This is the concept of equivalent resistance. The equivalent resistance of a circuit is the amount of resistance that a single resistor would need in order to equal the overall affect in the circuit. (2)

Parallel Circuit 

A Parallel Circuit (8)

A Parallel Circuit With A Broken Light Bulb (8)

When each and every resistor is connected together using a parallel connection, the circuit is referred to as a parallel circuit. In a parallel circuit, each device is placed in their own branch. This would mean that there is more than one way in which the charge can go around the circuit. This is the reason why a parallel circuit is more fail resistant than a series circuit and why a parallel circuit is used in household wiring. Each charge passing through the circuit will pass through a single resistor present in a single branch. When arriving at the branching location, a charge will make a choice as to which branch it will travel through back to the low potential terminal. (3) Adding an extra resistor in a separate branch will provide another pathway by which to direct charge through the main area of resistance within the circuit. The charge does not pile up or begin to accumulate at any given location such that the current at one location is more than at another location. Charge does not become used up by each and every resistor in such a manner that there is less current at one location compared to another. In a parallel circuit, the charge is divided up into each branch such that that there can be more current in one branch than there is in another. However, when taken as a whole, the total amount of current in each individual branch when added outside the branch. The current outside each branch is the same as the sum of the current in the individual branch. It is still the same amount of current, it is only split up into more than one pathway. 

In our textbook, the definition of each circuit (4) is as follow:

series circuit - a circuit in which loads are connected one after another in a single path

parallel circuit - a circuit in which loads are connected side by side

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The energy ball will not work on certain people due to the fact that in the body, sodium is used mainly electrically. (5) Sodium has an electrical charge and it is used in the body for various bodily function. Sodium was the natural source due to the fact that it is easily dissolvable in water and is also abundant in nature. However, the body does not make any sodium - it must be consumed. However, for some people losing a large amount of sodium will disturb the balance the cell is using in order to maintain a balance, causing the cell to not function properly. Salt is a good conductor to electricity. (6) In our body, the salt molecule is separated into chlorine and sodium. As the two separate from each other, the sodium has to lose an electron and give it up to the chlorine. In this way, the sodium is electrically positive and the chlorine is negative. They become a sodium ion and chlorine ion. It is the ion that cause our body to conduct electricity. This type of solution is called an electrolyte.

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Based on the activity done with the energy ball, I found that when we were doing the class challenge, after reading the problem, I understood what the solution was, however, I did not have the authority to tell everyone what to do, but rather I visualized it in my head and drew a small diagram on the board to represent what should be done in order to accomplish the task. I also realized that when I see something new and interesting, I usually want to touch it in order to find out more about it. I would rather learn by touching something and getting an up close view of the object than read about that same thing a text book. When my group and I were discussing the possible answer for each question, I found that I needed to write everything down in order to remember it and type it out on this blog. I usually remember information that I read better than information I hear. When my group was talking I toned out in order to write down my answer based on my previous experience of reading the topic in a book I read before. 

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Bibliography:

(1) Henderson, T. (n.d.). Two Types Of Connections. Retrieved from http://www.physicsclassroom.com/class/circuits/U9L4b.cfm

(2) Henderson, T. (n.d.). Series Circuits. Retrieved from http://www.physicsclassroom.com/class/circuits/U9L4c.cfm

(3) Henderson, T. (n.d.). Parallel Circuits. Retrieved from http://www.physicsclassroom.com/class/circuits/U9L4d.cfm

(4) Hobson, A. (2003). Physics: Concepts And Connections. Upper Saddle River, N.J.: Prentice Hall/Pearson Education. 

(5) (2011). What Does Salt Do To The Body?. Retrieved from http://lifewisdomcorner.com/wordpress/2011/02/06/what-does-salt-do-to-the-body/

(6) Basic Chemical Production Of Electricity. (n.d.). Retrieved from http://imet.csus.edu/imet1/antares/folio/teaching_units/echem/echem.htm

(7) (n.d.). Energy Ball At Steve Spangler Science. [Web Photo]. Retrieved from http://www.stevespanglerscience.com/product/1406

(8) (2012). It's Electrifying!. [Web Photo]. Retrieved from http://kimberleyparkss.eq.edu.au/home/jmann30/science.html