Questions

1. What device supplied the energy needed to split the water molecule into its component atoms?
   (The 9-volt battery supplied the electricity needed for this process.)
2. What are the components of water that are released during its decomposition?
   (Hydrogen and oxygen gas.)
3. Why did you need to expose graphite on both ends of each pencil?
   (You needed to expose both ends of the conducting surface.)

Inferring
Why didn't gas bubbles collect along the wooden shaft of the pencil?
(Wood is not a conductor of electricity. Therefore, gas generation was limited to the exposed graphite surface.)