The first color television sets for this system were sold in 1954. They used a 15 inch screen. Later that year, 19 inch sets were made, and by 1955 all sets were made with a 21 inch picture tube.Several manufacturers made 15 and 19 inch sets, most in very small quantities.he most comprehensive website on early color history is by Ed Reitan. The first set was made by Westinghouse, and sold for $1295. RCA introduced the CT-100 a few weeks later, at a price of $1000. GE sold its 15 inch set for $1,000, Sylvania's cost $1,150.
When routines and procedures are carefully taught, modeled, and established in the classroom, children know whatâs expected of them and how to do certain things on their own. Having these predictable patterns in place allows teachers to spend more time in meaningful instruction.
Classroom walkthroughs play an essential role in professional development for teachers. Though they are non-evaluative, classroom walkthroughs present a challenge to many administrators who struggle to properly record and then later convey the results of their time in a teacherâs classroom.