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Originally Posted by geoffretired Thunk, you have probably heard of the theory in a slightly different context.
Railway lines always had spaces to allow for expansion, didn't they. Now they have found the ground expands at the same time to compensate so they can produce seamless lines. No clickers!" Ooops that is archery related.
Another reason why you haven't heard of it is that it depends on so many things.
If the soil is heavy, no air etc it expands very little. Light airy soil expands much more due to the gasses present (gas expands more than solids usually)
If the measuring is done early before the targets are shot at, there is more chance of a temperature increase; so more expansion.
If you shoot on a ground that has permanent markings, and they were measured when the ground was cold, hot days produce low hits!
Carbon covered arrows shot with a clicker tend not to show the symptoms, as they expand so much the extra drawlength offsets the extra distance.
Obviously, that is just an over simplified version of the situation.  |
I'd like to see someone trying to measure accurately enough to spot any change.
I'm sure we could find someone who could calculate the thermal expansion coefficients of the common minerals that make up most soil. You will probably find that the change is negligible. In fact any expansion of the indvidual grains my simply act to close up the poer space, thus expelling some of the iterstital gases.
Ever considered that the arrows land lower because the limbs are softening in the heat?
22-08-06, 01:52 PM
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