6. Molds & Casts

1. 6.Molds & Casts • EQ: How do fossils provide a record of Earth’s geologic history? • Learning Target: I can compare and contrast the methods of mold and cast fossil formation. • Learning Task: I will use play-doh to create a mold and plaster of paris to create a cast fossil. I can compare and contrast these types of fossils. • Warm Up: Types of Fossils • Molds & Casts Lab; Fossils over Time • Molds vs. Casts – compare/contrast – in pages on iPad

2. Welcome! Warm Up Monday 4/3/14 • What are the 6 different types of fossils? Amber Mold* Cast* Carbon Film Trace Petrified

3. 4th Quarter Table of Contents 1 Title Assignment # Ice Cores 2 Ice Core Webquest 3 Fossil Notes 4 Getting into Fossil Record Webquest5 Fossil Vocab 6 Fossils over Time (Molds vs Casts) 7

4. Molds & Casts • Today we will use modeling clay and plaster of paris to create mold and cast fossils • Materials (Groups of 3 students) • Tray with 8 Plastic Fossils & Fossil Guide • 1 stick of modeling clay • 1 cup of 10ml of plaster of paris • 5 ml of water • 1 craft stick • 1 piece of wax paper with masking tape • 1 sharpie to label tape with your names

5. Molds vs. Casts • Decide which fossil your group would like to use. Ones that are medium size and have texture work best. • Break your modeling clay in ½ • Work the halves of clay into 2 smooth, flat, evenly thick disks • Press your fossil into one disk and place the other on top to make a fossil sandwich. • Carefully peel away the clay on one side, and then remove the fossil. • You may have to do this several times to make sure you have not torn or created holes in the clay Google Drive: 6.Molds vs Casts Worksheet Take picture of your molds and insert into your document.

6. Molds vs. Casts • Place the clay on your wax paper • Your Science teacher will add approximately 5 ml of water to your plaster • Use the craft stick to mix the plaster and water. It should be the consistency of pancake batter • Using the craft stick, pour ½ of your liquid plaster into each mold until level with the clay • Write your groups names and fossil onto the wax paper and place on the back shelf to dry • Complete Worksheet Day 1

7. Fossils over time (Molds vs Casts) 7 • Using the chart on page 336 of your book and your Fossil Guide, arrange the 8 fossils in your tray in order based on the Period of time when they lived. • Copy the first 3 columns of the Geologic Time Scale on page 336 into your notebook on page 32 • Next to the respective Periods, draw the appropriate fossil and label its name as given on the Fossil Guide

8. Example of what the chart you create in your notebook might look like:

9. Example of what the chart you create in your notebook might look like:

10. Answer the Questions about the fossils http://goo.gl/Vt2UvN • Which “fossil” is the oldest? • Which “fossil” is the youngest? • Describe the different Ammonites • How have the Ammonites evolved over time? • Describe the different Brachiopod shells • How have the Brachiopods shells evolved over time? • Describe the different Trilobite • How have the Trilobites evolved over time? • Why might the Trilobites be curled up? • Would these “fossils” be molds or casts?

11. Teacher Set up Lab * Fossils and Fossil Guide are in ziploc bags Sample of students mold and cast

12. Used Walmart clay .97 and the scoop is 5ml Teaching Aid brand 2 scoops of plaster per cup and About 1- 1 ½ scoops of water