def construct(self):
    equation = TexMobject('{ds', '\\over\\,', 'dT}', '(T)', '=', 'v(T)')
    (ds, over, dt, of_T, equals, v) = equation
    equation.next_to(self.get_pi_creatures(), UP, LARGE_BUFF)
    equation.shift(RIGHT)
    v.set_color(VELOCITY_COLOR)
    s_words = TextMobject('Tiny change in', 'distance')
    s_words.next_to(ds, (UP + LEFT), LARGE_BUFF)
    s_words.shift_onto_screen()
    s_arrow = Arrow(s_words[1].get_bottom(), ds.get_left())
    s_words.add(s_arrow)
    s_words.set_color(DISTANCE_COLOR)
    t_words = TextMobject('Tiny change in', 'time')
    t_words.next_to(dt, (DOWN + LEFT))
    t_words.to_edge(LEFT)
    t_arrow = Arrow(t_words[1].get_top(), dt.get_left())
    t_words.add(t_arrow)
    t_words.set_color(TIME_COLOR)
    self.add(ds, over, dt, of_T)
    for (words, part) in ((s_words, ds), (t_words, dt)):
        self.play(FadeIn(words, run_time=2, lag_ratio=0.5), self.students[1].change_mode, 'raise_right_hand')
        self.play(part.set_color, words.get_color())
    self.wait()
    self.play(Write(VGroup(equals, v)))
    self.change_student_modes(*(['pondering'] * 3))
    self.wait(3)
def construct(self):
    equation = TexMobject('{ds', '\\over\\,', 'dT}', '(T)', '=', 'v(T)')
    (ds, over, dt, of_T, equals, v) = equation
    equation.next_to(self.get_pi_creatures(), UP, LARGE_BUFF)
    equation.shift(RIGHT)
    v.set_color(VELOCITY_COLOR)
    s_words = TextMobject('Tiny change in', 'distance')
    s_words.next_to(ds, (UP + LEFT), LARGE_BUFF)
    s_words.shift_onto_screen()
    s_arrow = Arrow(s_words[1].get_bottom(), ds.get_left())
    s_words.add(s_arrow)
    s_words.set_color(DISTANCE_COLOR)
    t_words = TextMobject('Tiny change in', 'time')
    t_words.next_to(dt, (DOWN + LEFT))
    t_words.to_edge(LEFT)
    t_arrow = Arrow(t_words[1].get_top(), dt.get_left())
    t_words.add(t_arrow)
    t_words.set_color(TIME_COLOR)
    self.add(ds, over, dt, of_T)
    for (words, part) in ((s_words, ds), (t_words, dt)):
        self.play(FadeIn(words, run_time=2, lag_ratio=0.5), self.students[1].change_mode, 'raise_right_hand')
        self.play(part.set_color, words.get_color())
    self.wait()
    self.play(Write(VGroup(equals, v)))
    self.change_student_modes(*(['pondering'] * 3))
    self.wait(3)