Bone structure

Class: 3

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

Procedure:

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.

In class:

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.