11/19/09

Eggsperiment Results

Egg Shell Durability

Purpose:

A good test of a model rocket’s ability is to fly a raw hen’s egg in its payload compartment and retrieve it unharmed. It is a scalable feature for people in spacecraft. But just like a space agency will pick and choose its astronauts to minimize the potential of injury or unconsciousness, certain eggs will hold up better than others in a model rocket at seven g’s.

Materials:

  • Store-bought large grade A hen eggs
  • Homegrown leghorn (white)
  • Homegrown barred rock (brown) 
  • Homegrown araucana (green)
  • Or any other type of chicken egg you have at your disposal
  • Modeling clay, sand, or ballast of your choice 
  • Big bowl
  • Triple-beam balance
Methodology:

(a) Place egg under big bowl.
(b) Gently place more ballast into bowl until egg breaks (gently because you don’t want more acceleration than 9.8 m/s2).
(c) Weigh the ballast and the bowl.
(d) Repeat for each type of egg.

Data:

(#Test, egg type, mass held when crushed)
  1. Store-bought egg from Aldi: 2712g = 2.712kg
  2. Store-bought egg from Aldi: 2296g = 2.296kg
  3. Brown: 3128g = 3.128kg
  4. Brown: 3336g = 3.336kg
  5. White: 3636g = 3.636kg
  6. White: 4493g = 4.493kg
  7. Green: 3534g = 3.534kg
  8. Green: 3169g = 3.169kg
Calculations:

Average force to crush Aldi eggs:
F = (m*g + m*g)/2 = (2.296kg*9.8m/s/s + 2.712kg*9.8m/s/s)/2 = 24.50N

Average force to crush brown eggs:
F = (3.128kg*9.8m/s/s + 3.336kg*9.8m/s/s)/2 = 31.67N

Average force to crush white eggs:
F = (3.636kg*9.8m/s/s + 4.493kg*9.8m/s/s)/2 = 39.83N

Average force to crush green eggs:
F = (3.534kg*9.8m/s/s + 3.169kg*9.8m/s/s)/2 = 32.84N

Discussion:

No space agency would pick an astronaut that blacks out at 4g's. Therefore, it doesn't make sense to choose an egg that will scramble in its payload compartment if a force of just 24.5 Newtons is applied to it.

Conclusion:

Therefore, for maximum flight performance, the egg with the best qualifications is laid by the white leghorn. Moreover, a farm-fresh white leghorn egg should be used. The ratio of Newtons held by farm-fresh leghorn and Newtons held by Aldi egg is a staggering 1.63.

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