Unit 08“Impulse and Momentum”

Egg Drop Project

“Trouble Ahead”• You and a small group of friends when on a backpacking trip across Europe. • Suddenly you found yourselves stuck on the side of a cliff.• Unable to turn around and backtrack because of erosion and

rockslides, your only option is to jump to safety.• Luckily, you remember the unit on “Impulse and Momentum”

from Ms Bucci’s Physics class! Of course!• Using the items in your backpack, make yourself an apparatus that

you can sit in to prevent you from being hurt when you land on the ground below.

• Ms Bucci can’t actually drop you off a cliff, so instead we will use Eggs to represent people and drop the apparatuses from the 3rd floor window.

• Will you escape the cliff safely?!?!?!?!

Save Your Egg!!!• The purpose of the “Egg Drop Project” is to design an

apparatus, using the physics concept of momentum and impulse, which will keep an egg safe when dropped out of a window.

• On Wednesday December 17th groups of 2-3 students will design an apparatus with materials supplied by Ms Bucci.

• The apparatuses will be dropped on Thursday December 18th during class from the 3rd floor window.

• Those whose eggs do not break will win the competition!

• Egg Drop Packet will be due on Friday December 19th.

Egg Drop Techniques (to help keep your egg safe!)

The concept of Impulse can be used in two ways:

Change in Momentum: A smaller change in momentum will result in a smaller overall impulse!

Force and Time: Changing the amount of time to stop will change the amount of force needed to stop.

Egg Drop Techniques (to help keep your egg safe!)

Use the concept of Impulse: Change in Momentum to keep your egg safe.

•Momentum: p = mv•The less momentum the apparatus has, the EASIER it is to stop, it will have less Impulse!

•To have less momentum make an apparatus…– With a small mass (less mass, less momentum so use

light materials)– That will have a smaller velocity (by taking advantage of

air resistance if possible)

Egg Drop Techniques (to help keep your egg safe!)

Use the concept of Impulse: force and time to keep your egg safe

•Impulse: Δp = FΔt•The more time the apparatus has to stop, the less force needed to stop it! •Make an apparatus that give the egg more time to stop with:

– a cushion (so the egg can “sink in”)– a suspension (so the apparatus will “stretch out”)– a crumple zone (so the apparatus will “bend” or “break”)

More time to change the momentum of an object means less force applied to the

object.

Types of Protection When the object hits …

Cushion

Suspension

Crumple Zone

“Sinks in”

“Stretches out”“bends” or “breaks”

“Trouble Ahead”• You and a small group of friends when on a backpacking trip across Europe. • Suddenly you found yourselves stuck on the side of a cliff.• Unable to turn around and backtrack because of erosion and

rockslides, your only option is to jump to safety.• Luckily, you remember the unit on “Impulse and Momentum”

from Ms Bucci’s Physics class! Of course!• Using the items in your backpack, make yourself an apparatus that

you can sit in to prevent you from being hurt when you land on the ground below.

• Ms Bucci can’t actually drop you off a cliff, so instead we will use Eggs to represent people and drop the apparatuses from the 3rd floor window.

• Will you escape the cliff safely?!?!?!?!

Data and Observations:  Diagram: Please include picture of apparatus below. Identify key structural components of the apparatus.

List all of the features (suspension, crumple zone, cushion, and/or decreased momentum) you included in your design and what material was used for this feature.

Feature Material Used

Cups – crumple zone

baggie – to hold egg

Cardboard frame

Elastics - suspension

Group Name

Mass

Type of Protecti

on

Initial Velocity

of Impact

Impulse

Egg Broken/Unbrok

en

Class Data Table:

Calculations: Estimated Force applied if apparatus features succeed:

Estimated Force applied if apparatus features fail:

Initial Velocity of Collision:

Impulse (Change in Momentum):

∆y = ½(Vi + Vf)∆t

∆p = mVf - mVi

∆p = F∆t

∆p = F∆t

Vf here is the Vi of collision

Conclusion Questions:1. The features you listed in your diagram helped to protect your egg as the

apparatus hit the ground. Choose two of the listed features and explain how they were designed to keep the egg safe. Include concept of impulse-momentum theorem and results for time and force. (A.E.S.)

2. Did your egg break? • If YES: What are some ways you could have changed your apparatus

to prevent the egg from breaking?• If NO: What are some flaws you apparatus may have that could cause

the egg to break when dropped from the roof?

Egg Drop

Project Designs

When you make your design…

• Try to create an apparatus that allows me to see the engineering principles (how you are keeping the egg safe).

• Protect your egg on all sides! – Who knows how or where it will land!

• Make sure your apparatus is the “right fit” for an egg.– Is your cushion too soft or too hard?– Is your suspension too strong or too weak?– Is your crumple zone too easy or too hard to break?– Is there enough space in your apparatus for the egg to

have “more time? to stop.

Is your Egg Drop Project Design

the “right fit”?

Using Elastics to allow the egg to have more time to stop by “stretching” out…

This doesn’t allow the egg to stop more slowly by “stretching”. MAYBE it acts as a cushion, but definitely not enough cushion for this fall!

This is more like it!Attaching elastics so that they

will “stretch out” when the apparatus hits the ground!

Be sure to take your GOOD idea and make it GREAT!

maybe an elastic instead of a rope next time?

Don’t go bungee jumping with this guy!GREAT!

Good idea … a good frame, but work on protection!

Wouldn’t it be nice if you knew what was in this container?

Make the engineering visible!

Be careful in your design. You may see a great idea and copy it – but be sure you check to see if it’s the proper amount of protection for

the egg.

Survived! 2006

Broken! 2007

Space and Strength!Give it enough space and make it strong enough.

Stronger – but enough space?

Enough space – but strong?

Space and Strength!

Stronger – but enough space?

Enough space – but strong?

Give it enough space and make it strong enough to support the egg!

Choose a good frame so the engineering is visible!

Just cut holes in the box!

Protect your egg on ALL sides!

Did you just fill a paper towel roll with SAND?

Did you pay attention to the lesson on momentum?

… I just can’t even comment on this monstrosity …