Final answer:
To maximize effectiveness, a submerged aquarium heater should be placed near the bottom to facilitate even heat distribution throughout the water via convection currents. Positioning away from spots where heat might escape and ensuring the heater has proper circulation will also aid in maintaining consistent temperatures.
Step-by-step explanation:
To ensure that a submerged heater is most effective in an aquarium, it should be placed in an area that allows for optimal heat distribution. Since heat naturally rises, placing the heater near the bottom of the aquarium can help in evenly heating the water by allowing convection currents to disperse the heat. This action can be seen in forced convection, such as heat being conducted from a fire through a firebox into the room. Similarly, maximizing the exposure of the heated area to the rest of the aquarium will also help in evenly spreading the heat.
It is important that the heater is positioned in a manner that does not create hot spots or leave some areas unheated. To avoid power loss and ensure efficient heating, the heater should not be placed near the surface or close to areas where heat might escape quickly, such as aquarium windows or openings.