Reset Button. Most boilers have safety devices built in, so if these are tripped a simple reset may get your whole system working. The reset button is normally on the front of the boiler. Sometimes it's a dial that needs resetting to zero and turned back on.
A typical diffusion constant for a medium-sized molecule in water is about . If we want the smell to travel a quarter mile, or a little less than , we get a speed of. This speed is fantastically slow, and says that it would take ten million years for blood to diffuse out to a shark a quarter mile away.
The lemon shark can detect tuna oil at one part per 25 million--that's equivalent to about 10 drops in an average-sized home swimming pool. Other types of sharks can detect their prey at one part per 10 billion; that's one drop in an Olympic-sized swimming pool!