Weekly Photo Challenge: Edge (of Glass)

Why is glass green when viewed edge on? I wondered this today as I looked at the glass slats on the windows of our Tanzanian home. 

Google is a great resource for such trivia. It seems the colour is a result of iron impurities which impart a slight green tinge to most glass – the colour is amplified at the edge as you peer through a much thicker layer through  it’s length.

Apparently the iron is a legacy of the manufacturing process as it lubricates the passage of molten glass across  the smooth surface of molten tin during the formation of glass sheets. The only way to ensure flat glass!


So here is a submission to this week’s photo challenge edge.

2 responses to “Weekly Photo Challenge: Edge (of Glass)

  1. Pingback: Edge: High (1) | What's (in) the picture?

  2. It’s pretty amazing that you took the time to look it up. I wonder about everything I see and spend so much time looking things up. I remember the days when questions took you to the Library and started with those file boxes…the internet is moving us all along much faster.

    Liked by 1 person

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