SAASTE Technology/Activities/Conditioning-Strengthening\Waterproofing-2

Processing

Grade 7

Conditioning - Strengthening & Waterproofing
Conditioning is the process of changing the internal properties of a material. E.g. a piece of steel can be magnetised. There are two basic forms of conditioning; mechanical conditioning (when metal is hammered it becomes harder - clay that is fired becomes harder and stronger), and chemical conditioning (when we mix resin and hardener heat is given off (exothermic reaction) as the chemical reaction takes place. The product is hard and strong) There are a range of processes that can be carried out to condition a material; e.g. coating, mixing, impregnating, applying pressure, heat, energy, etc.

This activity will focus on the PROCESSING SKILLS of: Coating and Impregnating

You will need: ·
 * Glossy magazine paper / newspaper / tissue or toilet paper / small piece of sponge.
 * Wood varnish / wood glue / Nail polish
 * Optional:
 * Toothpicks
 * Paints
 * String

Activity
Cut the material into five (5) squares 50 X 50. Cut the sponge into two small pieces Leave one (1) square uncoated. Leave one piece of sponge plain.

Coating

1. Paint on the varnish onto test piece 1

2. Paint on the wood glue onto test piece 2

3. Leave to dry completely.

Impregnating

1. Dip test piece 3 into the varnish.

2. Dip test piece 4 into the wood glue.

3. Dip the piece of sponge into the varnish.

4. Leave to dry completely. · Conduct tests to check for waterproofing and strength of all the test pieces and compare to the originals. · Decide on a suitable way to communicate this information to your teacher. (graph, table, paragraph, drawings, etc)

Optional activity:
You can combine the knowledge and skill you have learnt in the activity above by trying the following. It is a practical task where you can combine strengthening and waterproofing into a small product. ·
 * Cut a piece of your paper (glossy magazine preferably) according to the template given.
 * Apply glue to one side of the template and roll onto the toothpick. Start rolling from the wide side.
 * Remove the toothpick and allow to dry.
 * Coat the finished product with varnish / nail polish.
 * Suggest three uses for the product that you made.



Author: Cheryl Jaftha

Contributions by Osman Sadeck

Reference: Living with Technology: 1993