Thanks to the soda/pop industry, 2 liters is a volume students are readily able to visualize. And, 2 liter soda bottles are readily available to use as a prop.
Ask students to imagine the soda bottle filled with gold (or silver or platinum). Use the internet (or newspaper) to find the current price for gold (gold is traded, thus the price fluctuates – get up to date information) as well as the density of gold. Then do the math (work through it with your students):
2L x 1000mL/L = 2000mL
2000 mL x 19.3 g/mL (density) = 38,600g
38,6000g x 0.035 (conversion unit) ounces/g = 1351 ounces
1351 ounces x $1,134.90 (price)/ounce = $1,533,249.90
Don't you wish you had a 2L bottle filled with gold!!!