Final answer:
In a circuit, cells are connected with the positive terminal of one cell to the negative terminal of the second cell to increase overall voltage in a series connection. Connecting cells in this manner allows for a complete circuit for current to flow through, as the electrons are repelled from the negative terminal and attracted to the positive terminal. Shorting a battery's terminals with a wire can cause overheating due to high current flow.
Step-by-step explanation:
The positive terminals of one cell in a circuit should be connected to the negative terminals of a second cell to create a series connection. This increases the total voltage available to the circuit because in a series connection, the voltages of individual cells add up. For example, if you have two cells of 1.5 volts each connected in series, the total voltage supplied to the circuit would be 3 volts. Connecting cells in series is essential for devices that require more voltage than what a single cell can provide. When connecting multiple cells in series, the positive terminal of the first cell is connected to the negative terminal of the second cell, and this pattern continues for all cells in the chain. This way, the voltage across the entire set of cells is the sum of the individual cell voltages. If a battery's terminals are shorted out by connecting them directly with a wire, the battery will begin to get hot due to the high current flow that results from the very low resistance of the wire. This can lead to overheating and potential hazards such as battery leakage or explosion.