Figure 50 is a mathematical graph. The horizontal axis is labelled “time” and the vertical axis is labelled “wave height”. Neither axis has measurement tick marks. The graph line looks like a sine wave. Following the graph line from left to right, it is first shown passing up through the origin rising at an angle of about 53 degrees. After that it starts to level out and briefly becomes horizontal forming a smooth peak some distance above the time axis. The line then proceeds to bend down until it is descending at an angle of about -53 degrees at which point it is crossing the time axis. The line then starts to level out again briefly becoming horizontal forming a smooth trough that is the same distance from but this time below the time axis. It then proceeds to bend up until it is ascending at an angle of about 53 degrees at which point it is crossing the time axis again. The line then starts to level out again briefly becoming horizontal forming a second smooth peak that is the same distance above the time axis. The line then proceeds to bend down until it is descending at an angle of about -53 degrees at which point it is crossing the time axis again. There is a vertical double ended arrow between the time axis and the first apex above the time axis. This arrow is labelled “wave amplitude”. There is a horizontal double headed arrow between the two apexes above the time axis. This arrow is labelled “wave length”.

 3.7 Looking at a standard: eye protectors