eLearning

Kenneth Buckle, a visiting scientist at the Center
for Integrated Manufacturing Studies at the Rochester
Institute of Technology, provides this answer:
When connected to a load like a lightbulb, a typical battery
undergoes chemical reactions that release electrons, which
travel through the bulb and are then reabsorbed by the battery.
(Devices that store mechanical energy also exist, but the most
common bat ter ies ,  such as those used in fl  ashlights and   remotes,
hold energy in chemical form.) Inside is at least one galvanic
cell, which produces between zero and several volts,   depending
on its chemistry. In a car battery, six cells, each contributing
two volts, are connected in series …

David W. Schindler
ABSTRACT
The results of bottle and mesocosm experiments
were compared with those obtained in whole-
ecosystem experiments at the Experimental Lakes
Area. Unless they can be cleverly designed to mimic
major ecosystem processes and community compo-
sitions, smaller-scale experiments often give highly
replicable, but spurious, answers. Problems with
appropriate scaling are difficult to deduce without
direct comparisons with whole-ecosystem experi-
ments. Reasons aremany, but include inappropriate
spatial scales to include whole communities, in
particular predators and nocturnally active animals;
temporal scales that are too short to assess accu-
rately the response of slow-responding organisms
and biogeochemical processes; and elimination of
key littoral–pelagic and catchment–lake interac-
tions. Identical studies of limnological processes in
lakes of a large …