6A20.41 • Reflection From Curved Surfaces: Projected Filament w/ Mirrors

Photo Shows the Converging Mirror Set Up for Classroom Use at the University of Texas at Austin.

Instructions / Notes:

• Turn on the light bulb in front of a concave mirror.
• Move the light bulb towards or away from the mirror focus the image on opposing wall of the classroom.

Photo Shows the Converging Mirror in use at the University of Texas at Austin.

• The demonstration also includes 3 aperture masks - which will reduce the utilized surface area of the mirror.
  • Show the effect of aperture size, with regards to the sharpness of the projected image that is seen on the opposite wall.
  • The room lights need to be switched-off when showing the smallest aperture mask.
• Last but not least - a convex mirror is used with the object between the class and mirror to show a negative focal point.
  • Use the meter stick to show a "virtual" reflected image of a second light bulb, which appears to be 2 meters away from the actual light bulb.
  • While taking care with the power cord - you must rotate/swing the rear of the table in an arc for most of the class to see the effect.

Demo Staff:

• Set up the projected filament and mirrors on a longish table, approx.a 6 footer.
• Place the table in classroom - so that its blocking three of the first row of seats towards the stair railing.
• This placement allows you to plug in the power cord to one of the electrical sockets on the first of seats.

Photo Below Shows the location in the Painter classroom - note the aperture masks - which are placed beneath the table.

Illustration is Provided by Courtesy of the University of Minnesota.

Last updated on August 30, 2017