GLASSES ... GLASSES ... We Don't Need No Steenking __GLASSES__!
Another way they can do this is via pinhole projection. Seems more educational too: Use either a pinhole at one end of a tube, and a mirror and screen or groundglass at the other; or use a "mirror pinhole" where a small clear area (e.g. 5mm) of a masked-off mirror reflects the image into a darkened room for group viewing. I built a pinhole telescope from a 9-foot-long mailing tube, a 2mm "pinhole" in aluminum flashing at one end; and a "dime-store" mirror at 45 deg, and a "groundglass" of one-side-matte drafting film at the other end. One can make real groundglass with ~500 grit abrasive. With projection telescopes you get a larger solar image. Mine was about 30mm dia. With mirror pinholes, the sky's the limit since you can utilize larger distances.