Using lasers to determine glass thickness Jordana Lowe Burnaby South Secondary Floor Location : M 213 P

The purpose of this experiment was to find a way to determine the thickness of glass with a laser pointer. By pointing a laser pointer at a sample of glass at a 45 degree angle, you can determine within a plus (+) or minus (-) 0.01mm accuracy the thickness by measuring the distance between the spots (reflected and refracted) that appear on the glass created by the laser pointer. Once measured, we charted all the distances between the refracted and reflected dots and the actual thickness of the glass. By creating a line chart with a best fit line we could then measure the distance between the reflected and refracted spots on a sample of glass with an unknown thickness and then proceed to predict the thickness of the sample by using the best fit formula. Next we measured the actual thickness of the piece of unknown glass with a calliper and compared this measurement to the one we predicted by the laser pointer technique and concluded that this way of measuring the thickness of glass is highly accurate. Our project is original because we are testing a theory that is based on a little known fact regarding laser spot behaviour on glass surfaces. Many glass making companies could use the basis of this technique to ensure that the glass being made has no major flaws i.e. does not vary in thickness throughout the sheet. All in all, our project proved to be very successful and informative.