1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Help with experiment

  1. Mar 11, 2008 #1
    I understand that this forum is way over and above what I need, but I am desperate and cannot find the answer anywhere. Other forums make you pay and I don't want to do that. Please have some mercy on me!

    I am a homeschooling mother and am working with my 8yr old on a science fair project. She is doing the dropping an egg and trying to get it not to break experiment. I don't know how much info you want, so I'll give you everything.

    We put the egg in a small cardboard box with cottonballs and added a simple parachute made from paper and string. The egg broke when we dropped it. We tried again and she wanted to add a second parachute and also more cottonballs. We added almost an entire bag of cottonballs and the box was so full we could hardly close the flaps. The egg did not break.

    We have been learning about parachutes and why they work, air resistance and everything. She decided she wanted to try to drop the box without the parachute to see what happens. The egg did not break.

    So, she knows instinctively that the packaging is what kept the egg from breaking and that is where I'm having problems. I cannot find any "science terms" to explain to her why the packaging helped. I have looked at inertia, all of Newton's laws, forces of objects when they hit the ground, but I can't find anything that tallks about why packaging helps objects to not break. I think it has something to do with the energy of the egg being absorbed into the cottonballs. I don't know!

    What I'm looking for specifically are terms with definitions and why those principles helped keep the egg from breaking. Thank you so much and I'm sorry if I'm posting this wrong or even in the wrong place. Thank you!!
  2. jcsd
  3. Mar 11, 2008 #2


    User Avatar
    Science Advisor
    Homework Helper

    It's acceleration. Force is proportional to mass * acceleration.
    One of the big 'lightbulb' moments in mechanics is realising that acceleration also applies to things stopping as well as cars setting off.

    What the cotton wool balls are doing is slowing the egg to a stop more slowly so the overall acceleration is less. It's exactly like you breaking gently in a car against slamming on the brakes. Car crumple zones and airbags do exactly the same thing.

    The parachute is also reducing acceleration but by making the initial speed lower, so you are de-accelerating form a slower speed to a stop in the same time.

    ps Congratulations on teaching this stuff - Keep up the good work and please ask here if there is anything else you need to know !
  4. Mar 11, 2008 #3
    Thank you so much for helping me out! That's what I needed to know. We've already been defining and talking about acceleration, terminal speed, mass, force and gravity so there's not really anything "new," just more in depth on the same things. Thank you for taking me seriously and answering my question. I really am grateful! Thanks!
  5. Mar 11, 2008 #4
    Wow! Great job! By 8 I wouldn't have dreamed of doing such cool stuff! As mgb said, if you ever need any help the people on this forum are more than willing to help. I don't know the physics behind this but I thought it was cool when i was small. Take an egg long ways from point to point and try to break it with one hand. It is vurtually impossible, it is related to the structure of the shell! Sorry, slightly unrelated, anyway goodluck with the rest of the experiment!

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook