Elephant Toothpaste

PROBLEM STATEMENT How does the amount of yeast added to hydrogen peroxide affect the time it takes the foam to reach the rim of the water bottle?

BACKGROUND INFORMATION Hydrogen peroxide is part hydrogen and part oxygen The yeast is a catalyst (a substance that causes a change in another substance)

HYPOTHESIS If _______________ (independent variable) has an affect _______________(dependent variable), then ___________ ____________ (provide an answer to your problem statement).

Materials 2 empty 16 oz water bottles 3 packets of yeast 240 mL of hydrogen peroxide Food coloring (color of your choice) 30 mL Dish soap 2 Funnels Timer 2 Cups 100 mL of warm water 2 spoons Graduated cylinder Goggles Tbsp

PROCEDURES Label your bottles “1 tbsp. yeast” and “2 tbsp. yeast” Place bottles side by side in tub or tray Place funnel on each bottle opening Pour 120 mL hydrogen peroxide into both bottles. (Hydrogen peroxide can irritate skin and eyes, so put on those safety goggles, and pour carefully). Add 8 drops of your favorite food coloring into each bottle. Add 1 tbsp of liquid dish soap into each bottle and swish the bottle around a bit to mix it. Mix 50mL of warm water and 1 tbsp. of yeast in a separate small cup, for about 30 seconds. Mix 50 mL of warm water and 2 tbsp. of yeast in a another small cup, for about 30 seconds. Pour the yeast water mixture into the appropriate bottle one at a time and start your timer Observe the time it takes the foam to reach the rim of the bottle. Record the time on your chart.

DATA BLOCK 1 BLOCK 2 # of Tbs Table 1 (Seconds) Table 2 Table 3 Average 1 x 18.91 8.81 8.27 8.99 2 8 11.7 5.03 19.46 11.04 BLOCK 2 # of Tablespoons Table 1 (seconds) Table 2 (seconds) Table 3 (seconds) Table 4 (seconds) Avg. (seconds) 1 5.2 X 12.75 5.25 5.8 2 3.3 2.76 4.35 2.6