New answers tagged chemical-biology
1
While we are alive, we are constantly replacing our molecules. With every breath cycle, you get rid of some of your carbon (CO2). With every meal, you take in new carbon (carbohydrates, proteins, lipids). The carbon in your body gets cycled as your cells die and are replaced. This replacement process stops when you die.
After this, whatever carbon remains ...
8
The metabolism of living creatures keeps the dynamic equilibrium of their $\ce{^{14}C/^{12}C}$ ratio with the enviromental $\ce{^{14}C/^{12}C}$ ratio via photosynthesis, breath, food and excrements.
It is not just about one time building, but also about continuous recycling of the body content.
Such an equilibrium means continuous resetting of the $t=0$ ...
13
There are plenty of good sources online explaining the principle behind radiocarbon dating. For instance, the wikipedia explains:
During its life, a plant or animal is in equilibrium with its surroundings by exchanging carbon either with the atmosphere, or through its diet. It will therefore have the same proportion of $\ce{^14C}$ as the atmosphere, or in ...
2
You seem to misunderstand the thermodynamics of evaporation: "Evaporation is an endothermic process, in that heat is absorbed during evaporation." It appears you are confusing evaporative cooling with a heat pump. In a heat pump, the compression half of the cycle changes the vapor back to liquid, which does make things warmer.
Consider boiling water at sea ...
0
The air at ground level in a forest will be shady - therefore considerably cooler than in full sun. That is probably the major cause/effect of the noticeable temperature change on entering a forest.
The leaves will be warmed by sunlight, cooled by evaporation. At the first bit of evaporation, the air could be warmed a little as the leaves are cooled a ...
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