The egg drop challenge is a physics design problem where a fragile egg must survive a fall, often from a height like 3 m. The goal is not to stop the egg from falling, but to control how it stops when it hits the ground. This makes the project a practical way to study gravity, speed, momentum, impulse, force, and energy.
Good designs use data and testing instead of guessing.
Key Facts
- Free-fall speed from height h: v = sqrt(2gh)
- For a 3 m drop with little air resistance: v = sqrt(2(9.8)(3)) = 7.7 m/s
- Momentum: p = mv
- Impulse: J = F_avg Δt = Δp
- Increasing stopping time lowers average force: F_avg = Δp / Δt
- Impact energy before stopping: KE = 1/2 mv^2 = mgh
Vocabulary
- Impulse
- Impulse is the change in momentum caused by a force acting over a time interval.
- Momentum
- Momentum is the product of an object's mass and velocity, written as p = mv.
- Stopping time
- Stopping time is the time it takes for the egg and package to go from impact speed to rest.
- Stiffness
- Stiffness describes how strongly a material resists compression or bending when a force is applied.
- Terminal velocity
- Terminal velocity is the maximum falling speed reached when air resistance balances weight.
Common Mistakes to Avoid
- Making the package too stiff, because a rigid shell can transfer a large force to the egg during a very short collision.
- Adding mass without a purpose, because a heavier package has more momentum and usually needs more impulse to stop safely.
- Ignoring how the egg is held in place, because a loose egg can keep moving inside the package and hit a hard wall after impact.
- Assuming the egg reaches terminal velocity from 3 m, because short drops usually end before air resistance can balance the weight.
Practice Questions
- 1 An egg package is dropped from 3.0 m. Ignoring air resistance, calculate its impact speed using v = sqrt(2gh) with g = 9.8 m/s^2.
- 2 A 0.20 kg egg package hits the ground at 7.7 m/s and stops in 0.050 s. Find its momentum just before impact and the average stopping force.
- 3 Two designs have the same mass and fall from the same height. Design A uses soft padding that compresses for a longer time, while Design B uses a hard shell with little compression. Explain which design is more likely to protect the egg and why.