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Forces and Simple Machines #4: Eggshell and Books Challenge

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Lesson Overview:

In this lesson, the children conduct a simple science experiment with eggshells and library books.  This is the only lesson in BiblioGarden that is designed to be a science experiment, so take advantage of this opportunity!  Building on the children’s work with forces, you will use library books to demonstrate how strong eggshells are.  My kids love this lesson, no one ever correctly predicts the outcome, and it is something they’ll be talking about all year.  So, pick up some fresh eggs, have a sponge and bucket ready just in case, pile on the books, and keep your fingers crossed!

Lesson Plan:

Suggested grades:



To measure the strength of four eggshells.  (AASL 2.2.3, “Employ a critical stance in drawing conclusions by demonstrating that the pattern of evidence leads to a decision or conclusion.”)  There is probably a better science standard, but this is the best I can do from within the librarian framework.

Suggested Time:

55-60 minutes

Success Criteria:

Each child will participate in testing the strength of eggshells with library books.  The books will push down on the eggshells.  This push can be measured in terms of kilograms or pounds of weight (technical, pounds-force as opposed to pounds-mass).

Lesson Outline:

1. Introduction:

Remind the students that every force is either a push or a pull.  (Link in case you want to revise this with DK Find Out:  DK Find Out!  What is a force?)  They might have different names like “thrust” or “lift” or “gravity,” but every force is a push or a pull.

Explain to the students that it is rare that the librarian gets to take part in a forces lesson, and even more rare for library books to be used in a science experiment.  But today is a special day because we’ll be doing a science experiment with books!

Ask the children what would happen if they went outside and dropped a raw egg on the pavement.  Everyone will predict that the egg will break.  Ask the children whether eggshells are fragile or strong.  They will almost certainly answer, “Fragile.”  Could an eggshell support its own weight?  Could an eggshell support more than its own weight?  Ask the students to make a prediction about how much weight four eggshells could support.  Ask the students to predict how many books the eggshells could hold.  As a comparison, how many books could they easily hold or carry in their school backpacks?

Tell the students that today, they will be testing their hypothesis using library books.  Have the class “number off,” then begin by giving instructions to the students one or a few at a time.

2. Main:

Ask the children to sit in a large circle around the experiment table.  It is important for the kids to keep their distance so that everyone can see and so that everyone can come up and participate.  Give instructions to children according to their number so that each child gets to be involved in several steps.  Ask the teacher to scribe the experiment and photograph the experiment as you and the children work.

The children will perform the action, but the steps of the experiment are:

  1. Cover table with plastic or protective sheeting.
  2. Set four eggs in bottle caps.
  3. Set four more bottle caps on top of the eggs.
  4. Position the eggs so that they are at the points of an imaginary square about the same size and shape as a book.
  5. Place the cardboard piece on top of the four top bottle caps. The cardboard should be touching all four top bottle caps and is used as a platform for the books.
  6. A few at a time, in numerical order, have the children take turns putting books on top of the cardboard platform.
  7. Continue placing books on top of one another until you run out of time or until the children are satisfied that the eggs can hold a lot of weight! Every child should get two or three turns to place a book on the eggs.  I usually stop the experiment before the eggs break.
  8. Once every child has placed two or three books on the pile, call a time-out and use the bathroom scales to weigh the books.

When I do this lesson with Grade 4 students, we focus on the scientific method.  Afterward, the teachers usually have the children write up the experiment using the scientific method template they’ve been working with in class.  My Grade 2s typically do not write up experiments, but they certainly can weigh the books and record their findings.

If your kids will be doing a write-up, instruct the children to return to their seats and use the teacher’s scribed notes.  At a minimum, Grade 2 children could write the:

  • Question (Example: How strong are eggshells?)
  • Hypothesis (Example: The eggshells can hold ten books.)
  • Conclusion or Findings (Example: The eggshells held 50 books!)

3. Conclusion:

If you have not done so already, take a group photo of the kids standing behind the books piled on top of the eggs.  Ask them if they enjoyed today’s experiment with library books and challenge them to find another experiment that they can do with library books.

  1. Low table in the center of the class carpet area.  (Experiment will be done on this table.)
  2. Four fresh eggs, roughly the same size.
  3. Eight plastic, screw-on bottle caps, all the same size.
  4. Plastic sheeting, tablecloth, or protective covering
  5. Cardboard piece large enough to span all four eggs when they are in place.
  6. Books from the classroom library.
  7. Bathroom scale to weigh the books after the experiment.
  8. Camera to photograph the experiment.
  9. Sample lesson with photos: https://littlebinsforlittlehands.com/eggshell-strength-experiment-kids-stem-activity/   (This lesson uses three eggs, but I prefer to use four.)
  10. (Optional) Scientific Method graphic organizers, one for each child. Use whichever one the teacher is using for the unit.  You can find a free one here:  Free Scientific Method Graphic Organizer

I have found that when working with full classes, it helps to assign each student a number.   This way you can make sure that all the children have an equal chance to participate.  Move in number order asking questions and having students take turns putting books on the pile.  For example, “Student #1, please spread the plastic sheeting over the table.  Students #2, 3, 4, and 5, set up one egg on top of one bottle cap.  Students #6, 7, 8, and 9, put the second bottle caps on top of the eggs.  Student #10, please position the eggs at the points of an imaginary rectangle, roughly the size of a book.  Student #11, please add the cardboard platform on top of the four eggs.”

Many versions of this experiment are available online.  Feel free to compare them.  I prefer the experiment using whole eggs, but there are sources which ask you to crack the eggs in half or punch a small hole and remove the contents of the egg.  I prefer using fresh, raw, untouched eggs simply because it’s less preparation for me.

We have found that the eggs easily support over 14 kilograms or 30 pounds.  I’ve had one class get the weight to 24 or 25 kilograms, which is as much as an airline suitcase.  The eggs are shockingly strong, so you don’t need to be afraid that the eggs are going to break early.

Recommended books for this lesson:


Key Terms:

Eggshells, Strength, Experiments, Scales, Hypotheses, Scientific Method

Eggshells and Books