If the batteries all have the same voltage, why not just use AAA cells for all battery operated devices? Let's find out.

AAA, AA, C, D batteries all are rated at 1.5 volts but besides the difference in physical size the amount of electric current they produce is also different. In this project the four battery types will be connected to a small hobby motor designed to operate with a 1.5 volt D size battery and a specific current. From the observations made a data table will be produced and the results will be displayed in the form of a graph.

Problem

What are the operating differences of AAA, AA, C, D batteries all with a 1.5 volt rating? Why will an electrical device that requires a 1.5 volt D size battery not operate as well with a 1.5 volt AA size battery?

Materials

AAA Heavy-duty carbon-zinc batteries

AA Heavy-duty carbon-zinc batteries

C Heavy-duty carbon-zinc batteries

D Heavy-duty carbon-zinc batteries

Masking or electrical tape

1.5 volt hobby motor

Tri-fold cardboard display board

Watch or clock

Procedure

Connect the hobby motor’s red (+) wire to the positive terminal on the D battery and the black wire to the negative terminal using strips of tape to hold the wire in place. Observe and make a note of the initial rotational speed of the motor’s axle using words like “fast,” “rapid,” “slow” “sluggish,” etc. Allow the m otor to operate continuously until the battery runs down. Record the total time that the battery operated the motor in a table similar to the one shown Repeat the same procedure for the C, AA, and AAA size batteries Using the data in the table plot a bar graph of length of time of motor operation along the Y-axis verses the various battery sizes along the X-axis.

Battery Size Length of Time of Motor Operation Observation of Motor’s Axle Speed D C AA AAA

Results

The metal case is lined with zinc which is attached to the negative terminal. There is a carbon rod in the center attached to the positive terminal. Between the carbon and the zinc there is a black paste made from manganese dioxide, carbon, and ammonium and zinc chlorides. Batteries labeled as “heavy duty” have a larger amount of zinc chloride and tend not to leak as easily. Alkaline batteries have a powdered zinc negative rod surrounded by a highly corrosive potassium hydroxide electrolyte surrounded in turn by manganese dioxide and carbon as an outer positive terminal. The word “battery” means a “line of many things.” (Note: the 1.5 volt batteries used in this project are really single cells and so are not really batteries, however, most people still call them batteries.)

AAA, AA, C, D batteries all are rated at 1.5 volts but besides the difference in physical size there is a big difference between them all. In an electrical circuit or device, there are two really important things: voltage and current. You can think of voltage like the water pressure that pushes things down a pipe, and current like the amount of water flowing down the pipe. Some electrical devices need a lot of current to operate but do not need a lot of voltage. That’s where battery size comes in. The D size battery will deliver more current than the C, AA, and AAA size battery. So even if a AA battery and a AAA battery are both rated as having a voltage of 1.5, the AA battery will deliver more current than the AAA battery.