6A20.41 • Reflection From Curved Surfaces: Projected Filament w/ Mirrors
Location: Cabinet 5
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.
- 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.
Last updated on June 8, 2026