Eggstraordinary Eggsperiments

Eggstraordinary Eggsperiments

Structural strength-architecture-arches-domes-acid-base reactions-forces and motion-properties of matter-materials and structures-chemistry-forces and simple machines-osmosis-density-extreme environments-physical education-grade 1-grade 2-grade 3-grade 4-grade 5-grade 6-grade 7-life science-earth and space science-physical science-air pressure-osmosis-inertia

The Unusual Structural Strength of Eggs!

Introduction

There are many easy and fun experiments that can be done with eggs, encompassing a number of different scientific principles. Such principles addressed in this resource include air pressure, acid/base reactions, osmosis, inertia, density, forces, and architectural structures.

In this resource, students will demonstrate several scientific principles by exploring characteristics of an egg's material and shape that make it so versatile.

Objectives

  • Relate the strength of an egg to its structure.
  • Use problem-solving skills in building solid structures.
  • Describe the effects of an acid-base reaction.

Background

Generally speaking, two of the main factors that contribute to the strength of a structure are its material and shape. This also applies to the material and shape of an egg.

Material

Calcium carbonate, or CaCO3, provides hardness and strength to things such as seashells, rocks, pearls, coral reefs, and eggshells. Since calcium carbonate is a base, it is no longer used for building purposes on its own (in limestone form) because it dissolves in acid rain.

A good quality eggshell will contain, on average, 2.2 grams of calcium in the form of calcium carbonate. Approximately 94% of a dry eggshell is calcium carbonate. The remainder is composed largely of phosphorus and magnesium, with trace amounts of sodium, potassium, zinc, manganese, iron, and copper. Immersing an egg in an acidic solution, such as vinegar, will disintegrate its shell through a common acid-base reaction.

Shape

An eggshell is a natural example of an arch. Arches, even those made of eggshells, are strong because they exert horizontal as well as vertical forces to resist the pressure of heavy loads. The crown of an eggshell can support a heavy load because the weight is distributed evenly along the structure of the egg.

Although the egg is strong in compression, it is weak in tension. Chicks are not strong, but by poking with their beaks from inside the egg, they are able to break out of their shells. They break the shell using tension. To make a structure strong with a tension weak material, such as an eggshell, forces must create compression and avoid tension. Fortunately, the arch/dome shape of the eggshell fulfills these requirements.

Entire Lesson

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Other Resources

Science World at TELUS World of Science | School Workshop | Structures

 

Comments  

 
#1 Activity Delivery tips — Eugene Luk 2012-03-08 13:25
•Eggs can be a messy program, so prepare for lots of broken eggs. Bring cleaning supplies, and clean up broken eggs after each activity before moving on to next one. If messiness or hygiene is a concern, use hard-boiled eggs for all activities.
•Bring a container of Wetwipes for the students as well (although if there's a sink readily accessible, encourage students to wash their hands w/ soap).
•Enforce a "Danger Zone" area around demo table to keep kids back, and keep the energy level in the session manageable.
•Egg Toss: check w/ school if you decide to use raw eggs. Staff may not appreciate broken raw eggs strewn all over school grounds.
•Unsqueezable Egg: begin your session w/ this demo. When this demo was test-run, egg did not break when pressed from the side b/w 2 fingers. You can address this 1 of 2 ways: 1) Use it as a teaching point for how strong eggs can be; 2) Use a spoon to tap the eggs, instead of pressing w/ your fingers - tap the top of the egg w/ flat part of spoon first, then tap the egg's side w/ narrow part of spoon. Conversely, hard-boiled eggs seem to crack very easily - even just holding it in one's whole hand did it.
•Eggstra-Strong Eggs: after activity, if class isn't too rowdy, have each student hold the stack of books themselves, so they can feel how much weight the eggs were supporting.
•Naked Eggs; Egg Drop: these activities take too long. Probably better suited for regular-school classes, rather than SSC sessions.
•Egg Volume Relay: kids found this really fun, but may be too advanced for primary SSC sessions.
•Egg in a Bottle: no need to grease bottle's mouth w/ oil; just use water instead. Ensure that inside of bottle isn't wet tho, as this will put out fire. Instead of lighting 3 matches, you can roll up 1 sheet of paper towel into a stick/tube shape, then light one end of the "stick" w/ a match and drop it into bottle.
•Eggstacle Course: if short on time, reduce # of obstacle stations. You can also adjust team sizes to contain as many students as there are obstacle stations. Either have all teams move from one station to the next in sequence, or have 1 facilitator each manning 1-2 stations.
•Egg-shaped Stress Ball: first/innermost balloon's colour doesn't matter - it's only there for an extra layer of protection. Stress balls can be prepped by pre-filling first/innermost balloon​ before the session.