About Cannons!

A cannon is a piece of artillery that launches a projectile by using gunpowder or other explosives. Cannons were first introduced in medieval China where they were used in warfare. Cannons were also popularly used during the World Wars. Cannons vary in size, range, angle of fire, fire power, etc; however, a cannon has several standardized parts.How does a cannon work?The rear of the main body of a cannon is referred to as a breech where fuel is deposited in and also allows combustible gases to escape through an air vent in it when the cannon if fired.
The central tube where the cannonball is held is called the bore. The central part is the point at which the weapon is mounted.
The cannonball is released from the muzzle which is the front of the cannon. The shape of the muzzle allows for a safe release of gases after the cannon is fired.


The Launching Angle
In order to maximize the horizontal distance travelled, the launching angle of a cannon has to be 45°. The maximum angle at which the cannon can be fired is 90 degrees; (since if the angle is greater than 90°, the cannon would shoot backwards or straight upward!) Using the equation d = (v²/g)sin2θ the best launching angle can be figured out. d is the horizontal distance, v is the velocity of the projectile, and g is the gravity. By plugging 90 degrees into the equation, the value of the theta can be found: 90/2 = 45°

Gizmos- Golf Range Quiz Results!

History of Flying Machines

Flight has been the dream of mankind and many models of flying machines have been designed and constructed; the first attempts were making wings out of feathers to be able to fly like birds . However, the dream of flight took many years to be achieved.


In the 1480s, Leonardo da Vinci was interested in flight and he had over 100 drawings that illustrated his theories on flight. After observing the structure of birds' wings, about 1485 he drew detailed plans for a human-powered Ornithopter (a wing-flapping device intended to fly). The modern day helicopter is based on this design. 

 

George Cayley was the first person to define the principles of mechanical flight and is considered one of the most important people in the history of aeronautics. Cayley created and constructed many designs of gliders. He discovered the four aerodynamic forces of flight which were weight, lift, drag and thrust.In 1849, his full-size model was large enough to support the weight of a 10 year old boy who was the first to take flight in one of his gliders. Later in 1853, Cayley built a larger model which carried Cayley's coachman as a passenger. 

 

In 1891, Otto Linienthal designed a glider that was able to fly a person safely for long distances. He did fundamental research on birds and the science of wing aerodynamics and he published a book on this subject in 1889. His designs inspired the Wright brothers. 

 

 

Samuel Langley built and designed machines that were driven by a steam engine. By 1896, he built an aircraft (Aerodrome No.6) which made a stable flight of 42 hundred feet in one minute and forty five seconds.

 

Aerodrome No. 6

Humans Can Fly!

After years of research and learning, Orville and Wilbur Wright known as the Wright brothers built the first heavier-than-air flight which was a plane weighing six hundred and five pounds in 1903. They combined the idea of gliders and engine power to create the "Flyer" which travelled one hundred twenty feet in two minutes. 

 

References: 

1) Flying Machines. (n.d.). The FLYING MACHINES Web Site. Retrieved March 25, 2012, from http://www.flyingmachines.org/  

2)History of flight. (n.d.). Retrieved March 25, 2012 from http://www.ueet.nasa.gov/StudentSite/historyofflight.html

3) Hatcher, D. (n.d.). Ancient Flying Machines. World-Mysteries. Retrieved March 25, 2012, from http://www.world-mysteries.com/sar_7.htm  

Right Hand Rule #2

The right hand rule #2 is used for coils.

It is used to determine the direction of magnetic field around a current-carrying wire and the conventional current flow.

When the coil is held with the right hand, the curved fingers point in the direction of conventional [positive (+)] current flow.

 


The thumb points in the direction of the magnetic field. The thumb also represents the north end of the electromagnet produced by the coil. 

Earth As A Magnet

Planet Earth is a giant magnet and just like magnets, it has a magnetic field. The magnetism of the Earth caused by the Earth's iron containing core. The activities and the movements of the hot liquid metals inside the core create an electric current which produces the magnetic field. To simplify, we can visualize Earth as having a giant magnet bar inside it. The North end of the magnet bar points to the geographic South pole and the South end of the magnet bar points to the geographic North pole. But why? To understand better, we can look at how a compass works. 

A compass consists of a lightweight magnetised needle and one end of this needle always  points towards the North. This is based on the "opposites attract" rule (north and south attract, south and south repel). As a result, the north end of the magnet is attracted to the Arctic pole which is actually a 'magnetic North'. 


There is a difference between magnetic North and true North. True North which is at the North pole, is the geographical direction represented on maps and globes by lines of longitude. However, a compass does not direct you to the true North. The Earth's magnet is not aligned with the geographical poles and because of this, a compass points to the magnetic North. The difference between magnetic North and true (geographical) North is called the magnetic declination. 

Unlike the true North, magnetic North does not remain constant because of the changes in the Earth's magnetism caused by the movement of Earth's inner core. Therefore, for accurate directions, a GPS is preferred over a compass since it uses satellite signals instead of the Earth's magnetic field.   




References:

1. Conger, C. (n.d.). Introduction to How to Find True North. HowStuffWorks "Adventure". Retrieved February 26, 2012, from http://adventure.howstuffworks.com/survival/wilderness/true-north.htm  
2. Nowikow, I. (2001) Physics : Concepts and Connections. Toronto/Vancouver, Canada: Irwin Publishing.
3. The Earth is a Magnet . (n.d.). The Earth is a Magnet. Retrieved February 26, 2012, from http://www.worsleyschool.net/science/files/magnet/earth/asamagnet.html

The Energy Ball Report

1. The main difference in a series and parallel circuit is the connection of the loads. In a series circuit, there is only one pathway through which the current flows (5). In this circuit the loads (such as the energy ball in our experiment) are connected one after another in a series. As a result, if the path of the current is broken, all of the loads would no longer work. For instance, if one energy ball stops working or if the switch is open, the rest of the energy balls in the circuit would stop working as well. Here is a diagram of a series circuit:                                                              

                                                                    Series Circuit (3)

 In a parallel circuit, the loads are connected side by side. A parallel circuit has branches and each branch provides a separate path for the flow of the electric current (4). Therefore, if one load (energy ball) does not work, the loads on the other branches would still work.                           

                                                                   Parallel Circuit (3)

3. The human body consists of mostly water in addition to salts and minerals which is what makes our body a good conductor of electricity and conducts the current in the energy ball. This is why the energy ball works when we hold it with our hands. However, the energy ball does not work on some individuals. This is most probably because the individual is dehydrated and their body does not contain the sufficient amount of water containing minerals and ions to conduct the electricity (2). Also, under conditions where the skin is very dry, the energy ball might not work because the skin is lacking water to conduct the current (1).

Self Reflection:

 From this experiment, I have learned that I have good teamwork and collaboration skills. I worked well with my group and I tried to participate actively in group discussions and listened to everyone’s insights. When the group members are willing to participate in the group, I think that group work helps me learn better by trying to discuss my ideas with my group members and learning from their knowledge and insights. In addition, since I am a visual learner, hands on work helps me remember the concepts better. For instance, holding the energy ball and forming parallel and series circuits with the class helped me learn more effectively. However, I think I should work on my leadership skills because during the classroom activity of making parallel and series circuits, I did not take action arranging the class into the circuits. I should also work on my time management skills and try to not leave my assignments for the last day.

References:

(1)     Q & A: The Human Body Resistance | Department of Physics | University of Illinois at Urbana-Champaign. (2008). The Human Body's Resistance . Retrieved February 11, 2012, from http://van.physics.illinois.edu/qa/listing.php?id=6793

(2)     How is water a good conductor of electricity?. (n.d.). PhysLink.com - Physics and Astronomy Online Portal. Retrieved February 11, 2012, from http://www.physlink.com/Education/AskExperts/ae61.cfm

(3)     MGB Class - SCIENCE. (n.d.). Science in MGB. Retrieved February 11, 2012, from  http://kimberleyparkss.eq.edu.au/home/jmann30/science.html

(4)     Parallel Circuits. (n.d.). The Physics Classroom. Retrieved February 11, 2012, from    http://www.physicsclassroom.com/class/circuits/u9l4d.cfm

(5)  The Series Circuit. (n.d.). NDT Resource Center . Retrieved February 12, 2012, from http://www.ndt-ed.org/EducationResources/HighSchool/Electricity/seriescircuit.htm