The Clock of Eons, Montessori RD

Natural History, 6-12

Clock of Eons – Geological Time Scale

The Clock of Eons is an impressionistic and factual material developed to provide the child with a global understanding the immense preparation that the Earth underwent before welcoming humanity. It is based on the analog clock, and is presented before the introduction of the Timeline of Life, which is the Phanerozoic Eon (Paleozoic, Mesozoic, and Cenozoic eras).

Montessori Research and Development has updated the name of this material based on current agreement from the scientific community. Additionally, their material informs the readers about factors that have influenced the life on Earth (temperature, tectonic plates, atmosphere…). Most of the Clock of Eons I’ve used did not have extensive information and work for independent work. Montessori RD has the most comprehensive package I found on the market.

The Clock of Eons from Montessori Research and Development follows the color patterns used on most Timelines of Life. Black represents nothingness, blue is for the oceans developing, brown is for the land emerging, green is for the vegetation appearing on Earth. Some clocks will have other colors such as yellow for life, and red for humans arrival.


The Clock of Eons set contains:

  • a control chart of the Clock of Eons with geological time scale
  • Descriptions cards for each eon and era
  • a puzzle chart with pieces
  • a linear version of the Clock (2 strips)
  • 17 cards with pictures, 17 cards with descriptions, 17 labels
  • 2 booklets to serve a control for the 3 part cards above
  • 4 wallcharts to recapitulate the information learning from the booklets and cards
  • a master copy of the Clock for the children to copy, color, label and more

How to use the Clock of Eons?

Montessori RD manuals – Presentation of Clock of Eons p. 136

The presentation for this material can be found in Montessori RD Manual History Elementary I, p. 136 (scripted). Typically, a child as early as 6 can be introduced to the Clock of Eons. The prerequisite would preferably be to have experience with an analog clock. This would improve the impression we want to leave on the child. Remember, some eons are 4-6 hours, whereas humanity is a few seconds.

You would also have had presented the Black Strip to the children, which represents the age of the Earth, with at its tip, a little strip of red. The red is us, humans on Earth, 200,000 years. This humility lesson is necessary for the child to develop an appreciation for life, and the work of nature. Nothing should be taken for granted.

The presentation of the Clock of Eons would precede the introduction of the Timeline of Life, as it is to demonstrate that the timeline is only a small part of the Earth history.

The linear representation (strip) of the Clock of Eons is usually aligned along the circumference of the Clock so that the child can see it in a linear fashion. It is similar to presenting a child with a globe and a map of the Earth on a plane (flat). You can use a string as well to show that each colored segment from the linear representation is equal to the same colored segment on the clock.

workable chart and parts. Linear timeline

After telling the story of the Earth, naming the eons and eras, describing the color coding, aligning the linear representation with the circumference of the clock, you are left many options. You can have the children manipulate the puzzle and pieces. You can read the three part cards with the children. You can offer them to label the outline. Or even better, you can encourage the older children to create their own clock using their mathematical skills and a protractor.

Taking the work outside

Following the presentation, you should have the Clock of Eons available for the children to explore. The wall charts should be temporarily posted on a wall to remind the children of the presentation, to invite the chart to continue exploring this amazing material using the three part cards and booklets. The booklets are full of valuable information, using age-appropriate scientific and sophisticated terms.

Materials to cut

Now you have prepared the field for discovering the Phanerozoic Eon.

Ready for a lesson?


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