0
Visit Your Local PBS Station PBS Home PBS Home Programs A-Z TV Schedules Watch Video Donate Shop PBS Search PBS
0
Rough Science
Explore the Challenges
Meet the Rough Scientists
About the TV Series
Discover More
Feedback
Site Map
Explore the Challenges

The Challenge: Make Soap



In this activity, we'll use a mixture of coconut and olive oil, with sodium hydroxide (sometimes called caustic soda), to make a solid soap. Homemade soap is particularly good for your skin because the glycerine formed as a byproduct of saponification remains in the soap, to soften your skin. The experiment takes about three hours, but your soap product will need to be 'matured' over a four- to six-week period before you can use it.

What You'll Need:

For 250g (about 1/2 pound) of soap, you'll need the following:

  • 32g (1-1/8 oz.) solid sodium hydroxide*
  • 125g (4 oz.) vegetable fat
  • 55g (1.7 fl. oz.) pure olive oil
  • 55g (2 oz.) white coconut oil*
  • 100cc (3.4 fl. oz.) distilled or rain water (not tap water) **
  • 5g (3/16 oz.) essential oil* of your choice, or the juice of a lemon (optional)
  • goggles
  • rubber gloves
  • cotton housecoat or apron (not nylon)
  • kitchen scales
  • plastic or glass measuring jug
  • 2 one-liter heat-resistant glass bowls
  • 2 plastic tablespoons (one for the oils and one for the sodium hydroxide solution)
  • thermometer (0 to 100°C / 32 - 212°F)
  • suitably sized plastic molds
  • newspaper

* available from most pharmacies or health food shops
** 1cc is the same as 1ml