Table 5 Descriptive codes assigned to unit plans

Science content domain

Life science

15

33

Physical science

18

39

Earth and space science

13

28

Engineering curriculum

Published curriculum

20

43

Made from scratch

26

57

Timing of engineering

Beginning

3

7

Middle

6

12

End

33

72

Throughout

4

9

Type of engineering instruction ^a

Design challenge

44

96

Problem/scenario

1

2

Presentation

3

7

Something else

1

2