Yeast experiment

OBSERVATION: BREADS HAVE TINY  HOLES.
QUESTION:WHY DO BREADS HAVE HOLE?
MATERIALS: 4 CUPS WITH 4 DIFFERENT KINDS OF TEMPERATURE. HOT, COLD, AND TWO NORMAL TEMPERATURE
CLEAR PLASTIC SHEET
SPOON AND BOWEL[OPTIONAL]
SUGAR
YEAST PACKET
WATER
PROCEDURE:FIRST PUT SUGAR , IN EACH CUP. THEN PUT DIFFERENT KIND OF WATER IN EACH. NEXT PUT THE YEAST PACKET IN EACH CUP AND WAIT FOR HOURS TO CHECK THE RESULTS.
CONCLUSION: THE CUP WITH NORMAL TEMPERATURE IS ABOUT TO BURST AND LOOKS LIKE A PIE.