Πραγματοποίηση μετωπικού εργαστηρίου στα πλαίσια της Χημεία Β΄ Λυκείου
«Παρασκευή σαπουνιού»
Τα παιδιά της Β΄Τάξης του Λυκείου μας παρασκεύασαν σαπούνι με την καθοδήγηση της κας Ευαγγελίας Κελεπούρη (χημικός) και με τη συνεργασία της κας Βασιλικής Τσικαλουδάκη (ΠΕ06) η οποία εξηγούσε τη χημική ορολογία στα αγγλικά, κάτι που είναι απαραίτητο για την κατανόηση της διεθνούς βιβλιογραφίας και την επικοινωνία στον επιστημονικό τομέα.
Soapmaking
Ingredients:
- 240 g olive oil
- 40 g sodium hydroxide
- 180 g water
Optional:
- desiccated and chopped up orange /lemon peels
- zest from oranges/lemons
- desiccated and chopped up rose petals
- oats
- cinnamon, cloves
- essential oils-fragrance oils
Preparation:
- After putting on your safety goggles and rubber/latex/nitrile gloves, add the sodium hydroxide solution to the water and stir it using an immersion blender (also called a stick blender) until fully dissolved (for 30΄). On no account should you inhale the fumes.
- Slowly add the olive oil in small drops and keep on stirring the mixture.
- Go on stirring constantly/non-stop (with the immersion blender) for 30-40 minutes until you get a cakelike mixture and it bubbles a bit.
- Add whichever ingredients are to your liking.
- Pour the soap batter into moulds (preferably soap moulds) and leave it undisturbed for 2 days until it is solidified.
- Take the soap out of the moulds and cut it into bars with a knife.
Cure time:
Let the bars of soap cure in the open air (from all sides) for 4-6 weeks. A freshly cut bar of soap is not fit to use because of its high acidity levels. So, it is highly recommended you give soap sufficient time to fully cure. In the meantime, your soap will be rid of the caustic soda (or sodium hydroxide) it contains. White powder is formed on the surface (sodium carbonate-soda), which is an indication that the soap is now ready. The more time you give the soap to cure the better it performs (in terms of lather, mildness to the skin and longer duration). Upon its preparation, soap is brownish but as time goes on, it turns white (at this stage it is ready to use).
Observations:
Caustic soda (NaOH)/lye gives us hard soap while caustic potash (KOH) gives us soft soap.
Besides using the above-mentioned ingredients, we can also use:
1) Essential oils (chamomile, lavender, rosemary, rose, sage, myrrh, mint)
2) Others (honey, milk, kosher salt, green clay, seaweed)
3) Colouring (we can use artificial colouring or natural colours from fruit (e.g. strawberries) or spices (e.g. cinnamon, turmeric etc.). The reason is that soap is colourless.
