The change of color of the silver colloid upon aggregation is one of the unique properties of nanoscale materials. Please answer the following questions based on your observations and on the information provided above.
1. Based on your experiments above, can you explain the color change of the initially prepared colloid in terms of your measured absorption spectrum?
2. Is the change in your absorption spectrum with electrolyte addition consistent with expectations based on the shape and size dependence of the s-p absorption features?
3. Can you imagine what our world would be like if the observed variation of color with size, shape and aggregation were true of macroscopic objects? In particular, if this concept applied to silver coins, how would the color of silver coins change when they are stacked on top of one another compared to individual coins? Hint: assume that the color chart given above applies.