Nanotechnology | Colour of Gold | Practical Investigation Report | |

Introduction
Gold is a precious metal which has been used for years and when we think of gold we think of shining bars in a bank vault, coins or beautiful jewellery. When we think of gold it’s usually a shining yellow gold however can come in many colours. The colour of gold can range from red through the visible spectrum to purple and violet.

Aim
The whole point of this experiment was to create gold that wasn’t the colour gold. The aim was to find out how a variable amount of sodium citrate would change the colour of a gold solution. Meaning the hypothesis was: if more sodium citrate is added the nano particle size will increase and the colour of the gold …show more content…

Pour some of the diluted colloid into the curvette, place in the spectrophotometer and press go. Remember to take photos of what the readings are.

Results Amount of Sodium Citrate added in micro litres (μl) | Peak Absorbency | Peak Wavelength (nm)λ | 15 | 0.829 | 545.0 | 55 | 0.430 | 549.0 | 100 | 0.442 | 529.0 | 400 | 0.625 | 615.0 | 700 | 0.683 | 515.0 | 1000 | 1 | 545 |

Discussion
The results are rumbled to say the least. For peak absorbency the trend has a general shape of moving up, however the data from 15μl test skews the results greatly, and is most likely an error. The reason for it being an error is that it is the odd data point, when removed the peak absorbency has a very smooth curve going up the graph but when used the graphs skews in such a way the data is hard to represent with a practical line, this means the R2 value is really low: R2=0.6065.

The wavelength data points are all over the place, some of them do follow a visible trend but not the one the curve shows. The trend line created by Excel has an R2 value of R2=0.15 which is fairly far from zero, meaning it is hugely unreliable. Changing the order of the polynomial it is at can create a line with an R2 value closer to 1, but the line becomes hugely unpractical and doesn’t represent the information properly. The main data point that skews this part of the graph is the wavelength for 400μl of sodium citrate, as it’s too high in comparison to the other data points for