add check on screw head

[challenge-bot] / curriculum / challenge-bot.scm

diff --git a/curriculum/challenge-bot.scm b/curriculum/challenge-bot.scm
index 6aabb6ddea07497bd1b84a470e346dcf5d18e708..beefcb478d56110690adea9ffa0535f50fc85f6a 100644 (file)
--- a/curriculum/challenge-bot.scm
+++ b/curriculum/challenge-bot.scm
@@ -188,8 +188,8 @@
             [in the motor assembly, there are #4-40x1.25\" screws.
                 are those fatter, thinner, or the same thickness as the
                 #6-32x3/8\" screws?]))])
-     (p [the "32" part is a measurement of how close the threads are to
-             each other.
+     (p [the "32" part of "#6-32x3/8\"" is a measurement of how close
+             the threads are to each other.
              this is related to the angle of the thread, which is also
              called pitch.
              it is a count of how many times the thread wraps around one
@@ -202,7 +202,9 @@
                       the screw body?])
            (item [what about 2 inches?
                        how many times will the thread wrap around two
-                       inches of the screw body?]))]))
+                       inches of the screw body?])
+           (item [where can a tool exert turning force on
+                        the screw?]))]))
     (subsubsection
      :title [fasten the arduino board to the deck]
      (p [push the 6-32 screw into the deck from the underside and at the