First, cut the cardboard into 7 squares that are each as wide as a penny.. Next, mix 1/4 cup of vinegar and 3 teaspoons of salt in the bowl. Put the cardboard squares in the bowl to get them wet. Keep them in the bowl for a few minutes. Then make the battery by stacking the materials in this order: 1. Put a penny down. 2. Take a cardboard square out of the bowl. Shake it over the bowl so that it is not dripping . Then place it on top of the penny. 3. Put a nickel on top of the cardboard square. You now have one cell, or part, of the battery. 4. To start the next cell, put another penny on top of the nickel. Make sure the sides of the coins that touch are dry. Then add another cardboard square and another nickel. 5. Continue adding cells in the same order: penny, cardboard square, nickel 6. When your battery is done, a nickel will be on the top. Fill in the blanks to describe the steps for building the first cell of the battery. The first step is to put a square down. Next, you place a cardboard square. To finish the first cell, you place a square on top of the cardboard square.