Up to 32 students
Three 45-60 minute sessions
A fossil is the preserved remains of an organism which was alive at one time or another (trace fossils will be discussed in the next lesson). These remains can be preserved in many ways, as remineralized rock, as impressions, etc. Most commonly hard parts are preserved, like shells of crab-like creatures, bones, or sea shells.
Sometimes soft-bodied remains are found, these are rare but very important for scientists. Soft-bodied fossils, like those of worms, jelly fish and other organisms help scientists understand the diversity of life at the time period the fossil is identified to belong in.
This lesson asks students to choose a fossil and do some research on the fossil in order to gain a better understanding of one organism and its time period in greater depth.
1.Become familiar with how fossils (life) has changed through Earth's history.
2. Become more familiar with concepts in evolution.
3. Be introduced to mass extinction events.
Plaster of Paris
Images and names of preselected fossils
Note: fossil replicas are inexpensive and can be purchased through educator science stores on-line such as Carolina Biological Supply or Ward’s Scientific. Sometimes they can be found at discounted sites like Oriental Trading Company however the detail and quality will be substantially lessened.
Activity 1: L.I.N.K.
(Assessment opportunity for an introductory activity to a new unit)
Have each group of students write down ideas about fossils for approximately 3 minutes.
“What do you know about fossils? What are fossils? Where so we find fossils?”
Following the 3-minute activity ask students to look around at other group’s concept maps and inquire about vocabulary or concepts they may be unfamiliar. Maps may either be taken down and students prompted to write down what they may have just learned about the topic discussed or maps may be left up for duration of unit to be built upon at a later time in substitution for a word wall.
Give background discussion about fossils if the class has not produced sufficient proof of comprehension.
Activity 2: Funky Fossil
I recommend making each fossil different for each student.
Depending on your class dynamic you may either allow the students to choose a fossil for themselves or select one for them. If you have decided to just give out images move onto Activity 3. If you have fossils replicas have students watch you demonstrated a replication process first and then allow them of cast their own.
Plaster can get messy fast so you may want to test this process out first before engaging a whole class, it is relatively easy with a whole class if they are over the age of 8 years.
1. Use some craft clay and cover the top side of the fossil so that you have a clear and clean impression. You will want to use enough so that it is shaped like that of a bowl. If the fossil is flat take extra clay and build up shallow wall so that when plaster is poured in it doesn’t run off the clay.
2. Mix plaster with warm water until it is thick like mayonnaise. Too watery it will not harden properly and too thick it may not pick up the detail up wish. Because plaster reacts with water humidly plays a big role in how much water goes into a batch and how long it takes to dry, so sorry not exact science here.
3. Pour plaster mix slowly into clay mold and gently tap the bottom or bang on the table to help air bubble rise out of the mixture. Etch name into the back with a toothpick or pencil point.
4. Let plaster thoroughly dry, you will know it is dry because it will begin to heat up at first and then cool significantly, rarely will this process take more than 30 minutes. The students will get their replicas at the next class.
Conclusion and Wrap Up:
Have students add new terminology to their LINK.
Vocabulary to note:
New York State Scope and Sequence
Intermediate and High School Science Standards
Key Idea 1.2c, 1.2h - 1.2j
Key Idea 1.1b - 1.1f, 3.1a - 3.1g, 3.1j - 3.1l, 6.1d - 6.1e, 6.3b -6.3c
Students will write a report about their fossil. Students should address questions such as:
What time period it came from and what was the time period like, is it extinct or does it have similar relatives alive today, what kingdom it comes from, etc.
Students should be allotted a minimum of a week, the next class (when they get the cast back) is research time, and the third and final class is quick presentation day.