Ask the apprentice to mix a solution (#1) of 5 g Peters fertilizer and 50 g distilled water.

• Determine the percent concentration-by-weight of this solution.
  The basic formula is Weight of the solute divided by the combined weight of the solute and solvent equals percent concentration-by-weight.
• Example: 5 g ÷ (5 g + 50 g) = 5 g ÷ 55 g ≈ .09 or 9% concentration-by-weight.
• Calculate the density of this solution (#1).
  Divide the weight by the volume to determine the density in gm/ml.

Ask the apprentice to make a solution (#2) using 10 g of Peters and 50 g of distilled water.

• Determine the percent concentration-by-weight.
• Ask the apprentice: Why is the concentration-by-weight of solution #2 not double the concentration-by-weight of solution #1 since the solute is doubled?

and

• Ask the apprentice to use the formula to explain.