by: Omar Correa
Problem Statement:
The effect of electrolysis on water

Background Information:
Electrolysis refers to the method of passing an electrical current through a substance. In this experiment, we are doing electrolysis on water. Water is made up of one oxygen atom and 2 hydrogen atoms. Covalent bonds are what bind the atoms together. Hydrogen is an element that has the atomic number 1. It is an element that is very plentiful. It makes up about 75% of the chemical elemental mass in the universe. Oxygen is an element with the atomic number of 8. It is the third most plentiful element. Water can be found in a liquid, solid, and gaseous state. Water makes up about 70.9 % of earth’s surface. Water is also extremely important for the survival of most animals, including humans. Unfortunately, 95.5 % of that water is found in the ocean, 1.7 % in the form of glaciers and ice caps, another 1.7 % in groundwater, and 0.001 % in the air as water vapor. The water is going to be put inside of glass. Glass is a transparent, solid material that is amorphous, meaning non-crystalline. It is every solid thing that has non-crystalline structure or that is a liquid when heated, according to science. Another material that is used is pencils. Pencils are usually wooden writing materials (unless they are lead pencils) that include a long piece of graphite in the middle. The graphite is what writes and is protected by a clay border. The 2 pencils used in this experiment are going to be connected to 2 electrical wires and a piece of cardboard. Electrical wires are mediums that can carry electricity from one end to another. These wires are made of metals that generate electricity quickly. There are 4 types of wires. These are the triplex wire, panel feed wires, and non-metallic sheathed electrical wire. The cardboard that is going to be connected to the pencils is going to be a thin strip. Cardboard is the name for a strong heavy-duty paper. Cardboard can be made into layers to be stronger and more durable. Cardboard is really flammable so in the experiment proper caution has to be taken into account. Another material that we need is salt. Salt is a mineral that is made mostly of sodium chloride. Salt is a mineral that animals need in small quantities. When it is consumed in large quantities, it can be harmful and could cause high blood pressure. When the salt is added to the water in the experiment, it is expected to dissolve in it. The reason to put salt into the water is so that it helps conduct electricity better. The last material in the experiment is a 9-volt battery. The electrical wires are going to be connected to it in order to receive the electrical charge. This type of battery can be used for smoke alarms, alarm clocks, etc. this type of battery is most common as a PP3 battery. The battery has 2 connectors on one side. One connector is circular while the other one is hexagonal or octagonal. The circular connector is a positive pole while the other one is a negative pole. The independent variable in this experiment is the electrical wires because different wires generate different amounts of electricity. The dependent variable is the amount of water left in the glass of water. What stays constant throughout the experiment is the type of glass, the battery, the cardboard, the water, and the types of pencils.


  1. A 9 volt battery
  2. Two regular number 2 pencils (remove eraser and metal part on the ends)
  3. Salt
  4. Thin cardboard
  5. Electrical wire
  6. Small glass
  7. Water

  1. 1. Gather all the materials
  2. 2. Make sure to use protective gear (gloves, goggles)
  3. 3. Fill a glass cup with 8 oz of warm water
  4. 4. Pour a teaspoon of salt in the glass cup
  5. 5. Stir swiftly until dissolved and let it sit for 5 minutes
  6. 6. Cut a strip of cardboard to fit over the glass cup
  7. 7. Sharpen 2 pencils on both ends and push the 2 pencils through the cardboard with a distance of one inch from each other
  8. 8. Connect 2 electric wires from the top end of the 2 pencils to a 9 volt battery
  9. 9. Keep constant the same amount of water, length of electrical wires (6 inches), same # 2 pencils
  10. 10. Observe for 5 minutes as bubbles begin to form at the bottom of the pencil tips
  11. 11. Measure the amount of water left inside the glass cup and subtract it from the original amount
  12. 12. Repeat the trials 3 times