1. Incredible Edible (Hard-boiled) Egg By Sam Anderson and Eugene Hart

2. Objective Calculating the time required to reach 160°F or 71°C in the center of the egg (safe eating temperature) Quiz #3 uses the thermophysical properties of water Use the thermophysical properties of an egg yolk with the given geometry from Quiz #3 Use the thermophysical properties of an egg yolk with the actual geometrical measurements Boiling the eggs for the calculated times to verify To Determine if Quiz #3 is Accurate by….

3. Property Comparison Egg ≈Water (Quiz #3, r=1 in.) ρ=993 [kg/m 3 ] c p =4178 [J/kg·K] k=0.628 [W/m·K] α=k/ρc p =0.15e-6 [W/m·k] Bi=hr/k=16.2 C 1 =1.95 ς 1 =2.9 r=0.0254 m Egg properties 1 (r=1 in.) ρ=1131.74 [kg/m 3 ] c p =2639.76 [J/kg·K] k=0.3985 [W/m·K] α=k/ρc p =0.133e-6 [W/m·k] Bi=hr/k=25.49 C 1 =1.97 ς 1 =2.98 r=0.0254 m Egg properties 1 (actual rad.) ρ=1131.74 [kg/m 3 ] c p =2639.76 [J/kg·K] k=0.3985 [W/m·K] α=k/ρc p =0.133e-6 [W/m·k] Bi=hr/k=23.2 C 1 =1.97 ς 1 =2.98 r=0.0227 m

4. Calculations Approximate Analytical Solution Egg ≈Water (Quiz #3, r=1 in.) Bi=16.2 Tdone=160°F or 71°C T ∞ =21.39°C T i = 4.5°C t(71°C)=17 min. Egg properties 1 (r=1 in.) Bi=25.49 Tdone=160°F or 71°C T ∞ =21.39°C T i = 4.5°C t(71°C)= 9 min. 6 sec. Egg properties 1 (actual rad.) Bi=23.28 Tdone=160°F or 71°C T ∞ =21.39°C T i = 4.5°C t(71°C)= 7 min. 48 sec.

5. The Experiment

6. The Experiment Continued 84.6°C in the Center after 17 min. of boiling

7. The Experiment Continued 79.8 °C in the Center after 9 min. of boiling

8. The Experiment Continued 70.9°C in the Center! After 7.48 min. of boiling ≈71°C!

9. References 1 “Continuous Pastuerization of Egg Yolk: Thermophysical Properties and Process Simulation” by Gut, Pinto, Gabas, and Telis-Romero http://www3.interscience.wiley.com/cgi- bin/fulltext/118650543/HTMLSTART 2 http://www.incredibleegg.org/?utm_campaign=- &utm_medium=cpc&utm_source=Google&utm_conte nt=&utm_term=eggs&gclid=CJjM- beP36ACFQykiQodZHvD0A