Title: High-speed Imaging of Ice Nucleation in Water Proves the Existence of Active Sites Authors: Mark A. Holden, Thomas F. Whale, Mark D. Tarn, Daniel O’Sullivan, Richard D. Walshaw, Benjamin J. Murray, Fiona C. Meldrum and Hugo K. Christenson Publication details: Science Advances, 2018. Introduction: This text file lists and describes the data in this repository, which is associated with the journal article named above. The data used to construct the Figures are given in comma-separated values files. The raw images used to construct WDS maps in Figure S8 are also given, which contain the colour scales for the individual images. Files and description: Freeze-thaw video microscopy feldspar 001.csv Contains the data used to construct the plots in Figure 3A, 3D, S4B and S4C. The cycle column gives the run number in the cycle. The temperature give the water freezing temperature raw data in that particular cycle. Finally, the site column states from which site the freezing began. Sites are labelled numerically, beginning at 1, where each unique nucleation region is given a new number sequentially. These sites correspond to the circled areas on the micrographs in Figures 3 and S4. Freeze-thaw video microscopy feldspar 010.csv Contains the data used to construct the plots in Figure 3B, 3C, S4A, S4D and S4E. The cycle column gives the run number in the cycle. The temperature give the water freezing temperature raw data from that particular cycle. Finally, the site column states from which site the freezing began. Sites are labelled numerically, beginning at 1, where each unique nucleation region is given a new number sequentially. These sites correspond to the circled areas on the micrographs in Figures 3 and S4. Freeze-thaw video microscopy rose quartz.csv Contains the data used to construct the plots in Figure 6. The cycle column gives the run number in the cycle. The temperature give the water freezing temperature raw data from that particular cycle. Finally, the site column states from which site the freezing began. Sites are labelled numerically, beginning at 1, where each unique nucleation region is given a new number sequentially. These sites correspond to the circled areas on the micrographs in Figure 6. Drop freeze assay data.csv Contains the data used to construct the plots in Figure 4. The raw temperature data and fraction frozen for each experiment plotted in Fig. 4B are given in columns A-S. The Temperatures and calculated values of ns used in Fig. 4C are in columns A-Y (this also includes the unceratinties for thin section dop freeze assays). The data for the freeze-thaw experiment plotted in Fig. 4D are given in columns AA-AC. Site specific nucleation.csv The data for freezing at specific sites are given in this file. In columns A-G, data for the site displayed in Figure 5 A-B is given. The Temperature and frequency are used to plot the pdf in Fig. 5A. The nucleation rate, J, and Tempearture are used to plot Fig. 5B (with corresponding uncertainties in Fig. 5 E-F). This site is also plotted in Fig. 5C by normalising J by surface area, which is given in column G as ln R/A. The same data are given for two further sites, for which the corresponding plots are given in Figure S5A (data in columns I-N) and S5B (data in columns Q-V). Columns O and W give the ln R/A data for these two sites, used in Fig. 5C. The final data used in Fig. 5C is given in columns Y-Z, and represents the surface area normalised freezing rate for an array of droplets containing powdered nucleants, rather than site specific nucleation rates (which are then normalised to surface area). Finally, the temperature and frequency data required to plot the pdf's in Fig. S5C are given in columns AB-AR. Raman spectroscopy.csv Contains the baseline corrected data obtained for the rose quartz used in this study. This data is used in Figure S7B. Baseline correction was performed directly after aquisition using the WiRE software used for spectral aquisition. Edge Middle.csv This contains the data required to plot Figure S9. This data is obtained from the nucleation temperatures given in the freeze-thaw video microscopy files, where each freezing event is assigned as edge or middle depending on whether it could be distinguished from the three-phase line or not (contact line). This edge / middle assignment can be readily seen in the circled areas on the micrographs in Fig. 3/S4. Figure S8A.bmp This is the data collected from WDS mapping in the region of an ice nucleation active site. The first 5 panels (reading right to left, top to bottom), show the WDS maps for Fe, Pb, Sr, Rb and Ba. Panel 6 is an SEM micrograph of the same region. In panels 7-12, EDX measurements of more common elements found in feldspar are shown. The scales for the images are given on the right hand side of the figure. Figure S8B.bmp This is the data collected from WDS mapping in the region of an ice nucleation active site. The first 5 panels (reading right to left, top to bottom), show the WDS maps for Fe, Pb, Sr, Rb and Ba. Panel 6 is an SEM micrograph of the same region. In panels 7-12, EDX measurements of more common elements found in feldspar are shown. The scales for the images are given on the right hand side of the figure. Figure S8C.bmp This is the data collected from WDS mapping in the region of an ice nucleation active site. The first 5 panels (reading right to left, top to bottom), show the WDS maps for Fe, Pb, Sr, Rb and Ba. Panel 6 is an SEM micrograph of the same region. In panels 7-12, EDX measurements of more common elements found in feldspar are shown. The scales for the images are given on the right hand side of the figure. Figure S8D.bmp This is the data collected from WDS mapping in the region of an ice nucleation active site. The first 5 panels (reading right to left, top to bottom), show the WDS maps for Fe, Pb, Sr, Rb and Ba. Panel 6 is an SEM micrograph of the same region. In panels 7-12, EDX measurements of more common elements found in feldspar are shown. The scales for the images are given on the right hand side of the figure.