|Biology Demonstration Manual (Peace Corps, 1993, 35 p.)|
Lesson: Les os
Rationale: Demonstrate that calcium gives bone its firm structure by dissolving the calcium in acid.
Materials: cooked chicken bones (cleaned of meat and gristle) vinegar glass plastic/rubber band
Preparation a week in advance:
1. Place a bone in a glass of vinegar and cover with plastic. It will take about a week to dissolve the calcium depending on the size of the bone.
2. Test the flexibility of an untreated bone.
3. Test the flexibility of the bone soaked in vinegar.
Note: This can also be done with 20% HCI and will only take few days. HCI can be bought in Bangui at Cedox or other paint/hardware stores. Ask for "esprit de sel" or "acide hydrochlorique". To make 20% HCI add 540 ml of concentrated HCI to 460 ml of water.
Source: Silver Burdett Biology, p. 583 and T91.