Cycle 2 Week 23 Hands-On Science script for all ages - Egg Protector, by Robyn Cooper Today we are going to think like engineers. Engineers use science, math, and even art to solve problems. Our problem is to build a structure with enough ingenuity that you can insert a real egg into it, and drop the whole unit without the egg breaking. You will be given 50 craft sticks, rubber bands, 12 napkins, and a plastic practice egg. But for the real experiment, you will use a real egg.

Before we start science today, let’s sing the scientific method. [Sing the song, to the tune of Pop Goes the Weasel. “The Scientific Method is Question, Research, Hypothesis, Experiment, Analysis (clap!) and conclusion.”

We are going to talk about building Egg Protectors today. What’s our Question? How can I think like an engineer to build a structure with only 50 or fewer popsicle sticks, 12 or fewer napkins, and rubber bands, that would prevent my egg from breaking when I drop the whole unit from a high place.

Now, why would I care about building an Egg Protector? Let the kids brainstorm. Egg Protector projects help you explore the forces of gravity, force and acceleration. This project combines problem solving skills with the basic principles of engineering and physics. What an opportunity to apply what you’ve learned! Here are some other reasons you might care though. The same principles are important when you invent and design:

• Air bags in vehicles• Helmets to protect your skull, brain, and eyes• NASA’s “Spacecraft Lander”, which was a rover vehicle for landing on and exploring Mars• Perhaps applying science and math to solve problems will lead to you to be able to help

design the next space rover!

• What do you need to consider when you are designing Egg Protectors? Tell kids, “Don’t answer this yet, we’ll come back to it.”

Let’s do our research.

There are two main questions to ask in our research:• What do I need to consider when I build my egg protector?• What is the science of Egg Protectors? But to answer this last question, let’s first think about

what kind of work does Egg Protectors have to do?

Research: What do I need to consider when I build my egg protector?

For this Egg Protector project the goal is to create a padded enclosure which goes around the egg so that, when the egg is dropped from a high height, it does NOT break.

Here are the things you need to consider. You want a design that would reduce the amount of energy transferred from potential to kinetic energy ON the egg shell.

• You might consider how to:• decrease the final speed of the egg using air resistance, • increase the time of the collision using some sort of cushion, • transfer the energy into something else • How can you increase your unit’s ability to ‘deform’ without breaking upon it’s landing

You want:• the padding to be soft enough so that it cushions the egg from high-impact forces during

landing• the padding to be thick enough so that it deforms during the entire duration of impact

• If it's too thin it will reach its maximum deformation before the impact is over and the egg will break. Therefore it must be as thick as possible. You can use up to 12 napkins for this experiment, which are soft and can absorb impact. If the egg breaks you need to make the cushion material softer, thicker, or both.

• Each napkin adds more weight to your unit.• to build a frame around the padded enclosure so that it flexes and deforms during impact

(landing), so it will absorb some of the impact energy, and act as an additional buffer of protection between the impact forces and the egg.

The figure below shows a basic concept design for the Egg Protector enclosure plus surrounding frame, based on what was talked about here, but these inventors forgot padding, and one of them used straws and tape, not popsicle sticks and rubber bands.

Research: Now we are ready to discuss the science of the famous Egg Protector.

You’ve already had some clue about what we need to discuss here. What do you think?

• Energy• Motion• Gravity• Force• Mass• Acceleration

All those concepts apply! Let’s review.

Let’s go over our facts about energy!

What are two forms of energy? Two forms of energy are Kinetic and Potential!

What is potential energy? It’s stored energy! In Egg Protector, the unit will have potential energy when you hold it up high. When you drop the unit, potential energy turns into kinetic energy.

When the unit hits the Earth, the force of the impact will cause the acceleration of the unit to stop. How can you calculate Force? Force = Mass X Acceleration. Which of Newton’s laws is that one?

Newton’s Second Law of Motion! That’s right!

Newton’s Second Law of motion states that forces equals mass times acceleration. (F = MA) (to the tune of Happy Birthday) “Newton’s second law of motion states force equal mass times acceleration.”

Newton's second law deals with the relationship between an object's mass, its acceleration and the amount of force it exerts. Although weight doesn’t impact the speed of gravity, its race to the ground, its mass does impact its FORCE ON the ground. The heavier an object is, and the faster it is traveling, the more force it exerts. By reducing the amount of mass in the egg container, you are reducing the amount of force it exerts as it falls.

That brings us to Newton’s other laws of motion. You just had a reminder for the 2nd law. What are the other laws?

Newton’s First Law of Motion. Who knows it?

Newton’s First Law of Motion states that an object at rest tends to remain at rest and an object in motion tends to continue moving in a straight line at a constant speed unless an outside force acts upon it.

This law means that if the forces acting on a falling egg are equal, it will remain in its current state of motion. If a force greater than those acting on the egg is applied, it will accelerate. "Acceleration" means any change in velocity --

slowing down, speeding up or changing direction. If you hold an egg, the forces you are applying are equal and balanced, canceling out the force of gravity. Therefore, it remains motionless in your hand. If you let go of the egg, gravity becomes an unbalanced force and causes the egg to fall to the ground.

So what outside force acts upon “it”, the Egg Protector? The Earth. But also gravity, air resistance, and any other obstacles that get in the way of the fall.

What’s Newton’s Third Law of Motion?

Newton’s Third law of Motion states that for every action, there is an equal and opposite reaction.

That means when you exert a force on an object, the object exerts a force back on you. For example, if you were standing on a boat and pushed off of the dock, even though you were pushing the dock, the dock pushed back. This is what causes the boat to move away from the dock.

This concept is useful in understanding why an egg breaks when it strikes the ground; the ground is returning the force from the egg as it meets the ground.

What action is being done on the Egg Protector? The Unit will crash into the ground, causing downward force. Equal and upward force will act on the unit.

Using shock-absorbing materials can help reduce the amount of force exchanged between the ground and the egg.

In the catapult project you were trying your best to build up and store potential energy using tension. Most good catapults convert tension or torsion energy that was more slowly and manually built up within the device before release. NOW, in Egg Protector, you’re trying to transfer it.

Egg Protectors use the sudden transfer of energy from the force of the Earth to the force of the unit. You’re trying to transfer the impact onto the unit, instead of the egg. You can’t decrease the amount of energy acting on the unit, so you must transfer it.

Can energy be created or destroyed? This is the First Law of Thermodynamics. The First Law of Thermodynamics states energy cannot be created or destroyed.

You have to transfer that energy.

We learned what tension is during our bridge building contests. What is tension? Tension is a pulling or stretching force, acting outward.

Would it help if you created torque in your Egg Protector? We learned about torque when we did our experiments on week 16. Then the center of gravity is off the mass center, the object wants to spin. It would if you could get your unit to spin so it landed with the thickest part of the egg facing the greatest impact!

Great Egg Protector (and helmet, space rover and airbag) designers are ENERGY TRANSFER experts. The best Egg Protector designer is the one who can figure out how to transfer the most energy to the unit and not the egg, using the least materials possible, dropping the egg and its unit safely from the highest height.

Let’s talk about the materials you have for your Egg Protectors first (see below).

You will be given 12 napkins, 50 popsicle sticks, rubber bands, and 1 plastic practice egg to use for testing. (Ignore my alphabet, haha). Your team will come up with one design, so think carefully about what you’re about to hear!

Let’s make a hypothesis.

You’re hypothesis should be able to answer the questions:• What’s the best design for an Egg Protector, using only these supplies? Why?• What are the fewest amount of supplies you can use to effectively protect your egg?• How high can you drop your Egg Protector without breaking your egg?

Now let’s do our experiment.

Let the kids start building Egg Protectors with their families. They may even want to sketch their design on paper.

When you do your analysis at home, record how high your Egg Protectors successfully protected your egg. Design another structure if you want, and retest it. Go through the scientific method this way… Question, Research, Hypothesis, Experiment, Analysis (clap!) and Conclusion.” Try modifying the things in your Egg Protectors:• Create more tension - how many rubber bands or popsicle sticks will you use?• Use more or less padding - how many napkins? (What if you used something other than

napkins? This is not allowed in the official experiment)• Vary the distance between the egg and the outside of the unit• Drop the unit from different heights• Try causing torque by off-setting the balance of the unit

We will run a campus contest on week 24 together. Families will compete using just one final Egg Protector design. You will be limited to the supplies your director specifies.

If you like this, it saved you time and energy, you found it helpful, feel free to buy me a cup of coffee via paypal.

Send it as “friends and family” to rehcooper@gmail.com, or else Paypal charges a fee!

I’d be so very grateful!