From the Table of 100-Calorie Portions estimate the fuel value of the meals you prepare.
SUGGESTED AIMS: To compare the fuel value of the meals with the energy requirements secured in answering the Questions in Lesson CXXXI. To use these comparisons as a basis on which to plan meals more nearly approaching the desired energy requirements.
DIVISION THIRTEEN
YEAST BREADS: STIFF DOUGHS
LESSON CXXXV
YEAST—LOAF BREAD
EXPERIMENT 77: CONDITIONS FOR GROWTH OF THE YEAST PLANT.—(a) Mix 1 tablespoonful of flour, 1 tablespoonful of sugar, 3/4 cake compressed yeast, and 5 tablespoonfuls of cold water. Put 1 tablespoonful of the mixture in a test tube and mark the tube "a." Fill the tube nearly full of lukewarm water and stand in a warm place for 15 minutes. Examine, noting especially the appearance at the top of the test tube. What kind of substance (gas, liquid, or solid) has been formed by the growth of the yeast plants?
(b) Put 1 teaspoonful of the yeast mixture in a test tube, and fill nearly full of boiling water. Label it "b" and after 15 minutes examine. Is there any change in the contents of the tube? What has happened to the yeast plants?
(c) Put 1 teaspoonful of the yeast mixture in a test tube, fill nearly full of cold water, and label it "c." Surround it with cracked ice or, if the weather is cold, place it out of doors. After 15 minutes examine. Is there any change in the contents of the tube? Why do not the yeast plants grow?
(d) Surround the tube marked "c" with lukewarm water and stand in a warm place. After 15 minutes examine. Are the yeast plants growing? Does freezing kill yeast plants?