6. Complete the rest of the planning section of the Investigation planner by filling in the spaces provided.

Some possible investigation approaches are suggested below.

Because some of the better batteries take more than an average class period to run down, using two lamps in parallel as shown in the diagram will almost halve the time required. However, if you choose to do this, you must do it with all batteries to make it a fair test. Run the batteries continuously until the last lamp goes out. Stopping and restarting gives the battery a chance to 'recover' and will extend its life. You must choose when to stop timing each battery and do the same for all batteries. In the dark, a globe will faintly glow even when it is not visible in the light. Do not use a key switch because you will get tired holding it down.

You may have to invent a way of holding the bare wires onto the end of the battery. A rubber band may do, or bent strips of copper metal can be used.

7. Show your plan to your teacher before you get the equipment needed to complete the investigation.
8. Carry out your experiment.

9. Make sure that you describe your observations and record all your results in the Results section of your Investigation planner.
10. At the end of this investigation you should be able to answer your Research question. To get to this point you will need to complete the Conclusion and Reflection sections of the Investigation planner.

1. What have you learned from this investigation about how to choose batteries?
2. How could electrical energy stored in batteries be used in developing countries? Are there any problems associated with batteries in developing countries?
3. Would rechargeable wet batteries provide better solutions in developing countries?
4. Suggest any other research about the batteries that you think should be carried out.

You may have to refer to library books or the Internet for information.