What lesson is your hardest to teach, but still is one of your favorites? When I was classroom teacher, the squaring and cubing of binomials and trinomials were those lessons. However, to me, they were the epitome of a lesson that made a difficult concept more accessible by using materials brilliantly to illustrate concepts that are difficult to conceptualize. These materials also made the lessons more entertaining, engaging, and thought provoking. That was my goal with the Clock of Eras game. We essentially took the history of the Earth, which is no small matter, and condensed it down into the timeframe of a lesson!

            This lesson is actually several activities in one, and the amount of time that each activity is played depends on the relative length of the era according to the clock. The different games highlight the dominant life forms of that era, and the amount of time we play each game is the sneaky way I get the students to understand how one era compared to another. Because there are multiple activities happening in this lesson, you will need to be pretty organized, so I highly recommend having another adult helping during this game. However, this game perfectly encapsulates the Montessori Physical Education experience of learning through play by integrating the Clock of Eras classroom lesson and bringing it to life in fun games.

Clock of Eras Game

Montessori Physical Education

Introduction:  The Clock of Eras is an iconic material that helps students visualize the length of the different periods of the Earth. Part of its impressionistic appeal is to see how long different animals have lived throughout Earth’s history, and to come to the realization that humans have been on Earth for a tiny fraction of it. Even ancient animals like dinosaurs have only existed for a relatively small chunk of Earth’s existence. By playing the Clock of Eras game, your students will play games that represent the time periods in intervals that are proportional to the time on the clock. Instead of visually seeing the clock as a fractional piece, they will temporally experience the switching of one period to another, and feel how relatively short or long a period is compared to one another. By the time we get to the Phanerozoic Era (Paleozoic, Mesozoic, Cenozoic, and Neozoic), they will be listening and acting out cues instead of playing games because the time intervals go so quickly. By the end of the game, the students will be shocked when they get to be humans for a couple seconds of the whole game!

Materials: 

·      This game absolutely requires at least two adults

·      A large open space (such as a gym or field)

·      Lots of basketballs or large bouncy balls

·      Handmade cards with CO2 on one side and O2 on the other side

·      Hula hoops

·      Small balls (tennis balls or dodge balls)

·      Basketballs

·      Soccer balls

Minimum Number of Students Needed: While you might be able to be able to do this lesson with as little as six students, this series of lessons really does best with a full class (20+).

Prior Knowledge: They should have had the Second Great Lesson and be familiar with the Clock of Eras.

Presentation 

• For this example, we are going to use a 45-minute PE lesson time. You may have to make adjustments based on your individual setting. Because a Clock is broken up into 12 (the number of hours), we need to find a multiple of twelve that fits into our PE time. A 45-minute class can accommodate a playtime of 36 minutes (12 x 3). The remaining time will give us a small window for explanations between periods as well as for a conversation at the end.

• Here is the calculation for each era. With the clock of era material, one hour equals 375,000,000 years. In our example from above, one hour on the clock is three minutes. We are going to round our values just a little, but here is the basic breakdown of the eras for our PE lesson.

  • Hadean Eon – about six minutes

  • Archean Eon – about eleven minutes

  • Proterozoic Eon – about fifteen minutes

  • Paleozoic Eon – about two minutes

  • Mesozoic Eon – about one and half minutes

  • Cenozoic Eon – About twenty seconds

Here is an example of the Clock of Eras Material (unlabeled)

• The first period of the clock of eras is the Hadean Eon. It will be broken up into two sections, which means each section should be about three minutes (six minutes total for the Eon).  During the first section, the students will be slamming basketballs (or whatever bouncy ball they have) into the ground as high as they can. If they were outside, they would throw or punt soccer ball as high as possible over and over again. This action represents the chaos, heat, and collisions that were happening on Earth. Maybe the students will picture volcanic eruptions spraying lava into the air. There was no life; Earth was violent and inhospitable. The students are encouraged to be loud and noisy to simulate the chaos of this time as well.

• After three minutes, the teacher will gather everyone so they can “make rain.” The students will have to be completely silent for this to be effective.

  • First, the students rub their hands together.

  • Next, slowly point at students to stop rubbing their hands and instead begin snapping their fingers.

  • Once everyone is snapping their fingers, let it go for a while so the students can appreciate the sound of the trickling rain. Next, slowly point at students to begin slapping their legs instead of snapping.

  • Once everyone is slapping their legs, let it go for a while so the students can appreciate the sound of the hard rain. Next, slowly point to students to start snapping their fingers again.

  • Once all the students are snapping again, slowly point at students to stop snapping their fingers.

• The next period is the Archaen Eon. This period will last roughly 11 minutes. The students are going to cyanobacteria that are making food through the process of photosynthesis.

  • Place hula-hoops around the playing area. Each hula-hoop will either be a molecule of carbon dioxide or a molecule water based on the sports balls inside and what they represent. As an example, if the hoop contains to H2O, then it would have two soccer balls and a tennis ball inside. If the hoop contains carbon dioxide CO2, then it would have a basketball and two tennis balls.

  • Organize the atoms based on ball availability. Whatever ball you have the most should be oxygen. The next most abundant atom should hydrogen, and the one you have the least should be carbon. Below is an example of how you might organize your game:

    • Tennis balls will represent oxygen

    • Basketballs will represent carbon

    • Soccer balls will represent hydrogen

• In a perfect world, you would have six hula-hoops that would be a water molecule, and six hoops that would be carbon dioxide. If you can accommodate this, you will have the perfect amount to make a glucose molecule (C6H12O6), as well as six molecules of oxygen (O2).

  • Have all the students start in the middle of the playing area. They are going to be cyanobacteria, and they are working together to break apart and absorb the atoms from the water and carbon dioxide molecules. When the game begins, the students will go out to one of the hoops. Once they are there, they must break apart the molecule to be able to deliver the atoms back to the teacher. To break apart the molecule, students must:

    • Juggle the tennis ball(s) one hundred times

    • Bounce the basketball one hundred times

    • Dribble the soccer ball in-between their feet for 100 touches

• As pieces are being delivered to the teacher, the teacher can begin constructing a glucose molecule. A glucose molecule is (C6H12O6), which is the sugar energy that the cyanobacteria make for themselves. However, we will notice that there will be leftover tennis balls (oxygen). This means that after photosynthesis, the products are glucose and oxygen. Over a billion years, this freed up oxygen would radically change the atmosphere of Earth, which would make it possible for other life on Earth as well.

  • If there is time left, play this game as many times as you need until the time is up.

• The next period is the Proterozoic Eon. This period will roughly last 15 minutes.  This will be broken up into one 10-minute period and one 5-minute period.

  • The first game will represent some cells becoming Eukaryotes. A few of the students will be given hula-hoops. They will represent a new type of cell called Eukaryote cells. The majority of students will not have hula-hoops and are prokaryotes. The students without hula-hoops have their eyes closed during the game (they haven’t evolved to have eyes yet). They will be wandering around the playing area with their hands out.

  • One of the responsibilities of the teacher is making sure any wandering student doesn’t get too close to a boundary where they could hurt themselves. Remind students to have their hands out so if they fell something they know they should turn around.

• Everyone must walk during the game. The students with the hula-hoops will “capture” another student without a hoop by placing the hula-hoop over the head and around the body. Emphasize the importance of safety when putting the hula-hoop over them. This will symbolize that the cell didn’t just eat the other cell, but actually is harboring it and they are now working together. The captured student has become an organelle of the eukaryotic cell.

• Once a student is captured inside the hula-hoop, both students work together to try and tag another student who has their eyes closed. This represents this new type of cell “eating” another cell and getting energy, which is different from how the other cells were making food through photosynthesis.

• The tagged student inherits the hula-hoop, and they begin the hunt for a new student to turn into their organelle (they should not immediately put the hoop around anyone who tagged them). The previous two students now close their eyes and become part of the game to be hunted by the eukaryotes.

To get the full lesson plan write up, for free,  click on the link to download your Clock of Eras lesson plan!

If you are looking for a good downloadable Clock of Eras chart, here is the Teachers Pay Teachers link from Minkybubs Montessori.