Page 1 of 2
Contributed by:Discovery Centre 1.) Objective 2.) What You Need 3.) To Do and Observe 4.) What's Going On 5.) Parent/Teacher Tips Objective To separate water(H2O) into oxygen and hydrogen.
What You Need Two pencils (your every day HB pencil will work but #2's will work better) Two pieces of electrical wire about 30cm each A glass jar (approx. 500ml) Asquare piece of Cardboard large enough to cover the mouth of the jar Tape Water A lantern battery Salt To Do and Observe Sharpen both ends of each pencil. Be sure to remove the erasers and any metal partsfrom the end of the pencils before trying to sharpen the ends. Fill the jar to just below the top with water. Add a few tablespoons of salt to the water filled jar. Tape the piece of cardboard to thetop of the jar. Carefully, push one of the pencils through the cardboard so that the lead is completely under water. About three centimeters away, do the same with the other pencil. Be sure the leadsof each pencil are at approximately the same level under the water. Using the wire, connect the exposed lead of the first pencil to the negative terminal of the battery. That is, wrap one end of thewire around the lead and the other end around the negative terminal. Connect the exposed lead of the other pencil to the positive terminal of the battery. We should now have one pencil connected tothe negative battery terminal and another pencil connected to the positive battery terminal. The non-connected ends of the pencils should be submerged in the water. Bubbles should now begin to form atthe two submerged leads of the pencils What's Going On You have just created an electrolytic cell. The lead of a pencil is made of graphite which is a conductor. Electric current from the battery willflow from the negative terminal of the battery down through the lead, through the water and up the lead connected to the positive terminal. The lead attached to the positive terminal of the battery...