Experimental Procedure

1. Get several different types of materials to test from the hard parts from many different animal sources. Get as many different sources from as many different kinds of animals as you can. Use your imagination and the grocery store. Many grocery stores will give out soup bones for free.
2. Place each sample in a cup and label the cup with a description of the material.
3. Make initial observations of each sample. What does it feel like? What does it look like? Write down your observations in a data table, focusing on the similarities and differences between materials.
4. Pour vinegar into each cup until the sample is submerged, or covered, with vinegar.
5. Let your cups sit at room temperature for several days. Check the cups once in a while to be sure that the vinegar is still covering the material in the cup. You may need to add more vinegar to the cup if necessary.
6. Remove the samples from the vinegar and then observe the materials. How do they look and feel? How do the textures compare to before treatment with the vinegar?
7. Write down your observations in a data table, focusing on the similarities and differences between materials.
8. How do endoskeletons and exoskeletons compare? Did they react with the vinegar in a similar or different way? Do you think they are made out of similar or different materials?