The Physics of a Bow and Arrow
A bow and arrow operates on certain principle of physics. I will be investigating what factors affect the accuracy of a bow and arrow.

Figure 1 - The change in the shape of the bow as the archer draws it.
Figure 1 - The change in the shape of the bow as the archer draws it.
A bow is a basic machine called a “two-arm spring”. Energy is stored when the archer bends the bow. It may look like the string is being stretched, however, it is not stretched but the shape of the bow is changed. The stored energy is then transferred to the arrow in the form of kinetic energy. The greater the draw length, the greater the momentum and energy that the arrow gains. A longer draw length will influence your accuracy. You, as an individual, need to find the draw length that you are most comfortable with. With your own unique draw length you need to have an anchor point. This point is the place where your hand will be every time you shoot an arrow. This will greatly improve the accuracy of the shot.
Figure 2 - Correct form to shoot an arrow
Figure 2 - Correct form to shoot an arrow
In archery your form is very important. If you do not have the correct form then you will not be able to shoot properly and you might hurt yourself. In Figure 2 (left) we can see the correct form when shooting an arrow. Old military snipers used a technique they called B.R.A.S. Breathe. If you are do not breathe then you will not be able to focus clearly on where you are aiming. Breathing actually causes a shift in body weight that can influence your shooting extremely. Your breathing needs to be balanced and steady. Relax. Tensing up before you shoot is detrimental to the accuracy of your shot. You will not be able to keep your bow steady if your muscles are tensed up. Release your draw on the bow and start again if you are tense. Aim. To put it simply: If you do not aim then you will not hit your target. Shoot. When you have done all the above, you are ready to take your shot. Stay standing still and and keep looking at the target until you hear that the arrow has hit the target. Included in the correct form is the correct stance. Your side should be pointing to the target that you wish to hit and your feet should not only be less than your shoulder width apart but also not right next to each other.
Figure 3 - Effects of arrow spine on accuracy
Figure 3 - Effects of arrow spine on accuracy
Arrow spine is defined as the resistance of an arrow to bending or the stiffness of an arrow. The reason arrow spine is necessary is to counter what is called archer’s paradox. Archer’s paradox is essentially the bending of the arrow around the bow when it is fired and then it is still able to hit the target. Archeryphysics-mrsmith08.awardspace.com said the following about the diagram to the left: “As the diagram shows, an arrow with too little spine for the bow will not flex and as the string comes closer to the bow stave, the arrow will be forced off to one side. Too much spine, or flexure, will result in the arrow deforming too much and being propelled off to the other side of the target.” With arrow spine we need to consider the stiffness of the actual shaft material, the length of the shaft and the weight of the tip that will be used. Arrow spine is subdivided under static spine and dynamic spine. The static spine of the arrow shaft is how the arrow bends when it is supported at two points with a weight suspended in the middle. Dynamic spine refers to how the arrow bends when it is shot. Dynamic spine can be perfect for one bow but for another bow it might be too stiff or too flexible. The way you grip you bow has a big effect on how the arrow will end up hitting or not hitting the target. Your grip should only be tight enough to hold the bow in your hand. If you grip it too tight you will tend to twist your arm to the left or right and this will influence the way that the arrow flies greatly and it will therefore have a very significant impact on your accuracy.
Temperature is another major factor that affects accuracy. A perfectly tuned bow may shoot accurately at normal temperature but at an extremely hot or cold temperature the bow’s accuracy may be off. This change in temperature causes a change in the humidity of the air and how much the materials of the bow and arrow expand or contract. A person’s draw cycle will affect his accuracy. If it is jerky and uncontrolled, accuracy drops. However it is a smooth and controlled motion then you will have much more accuracy.

In conclusion I would like to summarise the things that affect accuracy in archery. The following things in no particular order affect accuracy: * Form * Arrow spine * Temperature * Draw Cycle * Draw Length * Anchor Point * Aiming

The way this has impacted the modern world is major improvements in sports. Archery is an Olympic sport and many people now compete and represent their countries. All the changes in archery have made great improvements in hunting. Archers are now able to shoot animals from a distance far away with precision and accuracy. The use of arrow versus bullets means that the meat of the game animal will not be damaged or polluted with the side effects from using bullets.

Bibliography
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Picture and Graph Acknowledgements
Figure 1 - HowStuffWorks - Bow and arrow http://www.howstuffworks.com/
Figure 2 – Royal College of Surgeons in Ireland – http://www.freewebs.com/rcsiarchery/archerygettingstarted.htm
Figure 3 - - http://archeryphysics-mrsmith08.awardspace.com/arrow.html