Science Buddies: "Ask an Expert"

We are building the simple motor from the website. The battery holders we got at radio shack have wires at each end. What do we do with them and does it matter which way tje batyery loads? Please help asap!

bbrinkley - Most likely your battery holder might be the type that uses AA, AAA, C or D batteries. If they have a red and black wire this would indicate the polarity when the batteries are properly installed. These cylindrical batteries have a small raised terminal on one end (positive,+, red wire) and a flatter base (negative, -, black wire). The spring terminal is the flat base, negative terminal. Insert all batteries the same way, flat base negative to the spring side of the terminal. Multiple batteries will be connected in series (positive terminal of one battery to the negative terminal of the next). This means that the voltage output of the battery pack is the sum of the individual batteries. A 2 battery holder will supply 3 volts,a 4 battery holder will provide 6 volts.

Rick Marz

Please post a link to the project you are referring to. One of the simple DC motor projects on the science buddies project ideas pages involves a single cell cylindrical battery with magnets stacked on both ends that uses a jewler's screw driver as a support bearing. For that project (https://www.sciencebuddies.org/science- ... k&from=TSW), a battery holder is not required and would actually complicate things.

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