Use 1-3% diatase, which is free from reducing sugars,or 1% bacterial amylase. These chemicals are available from Southern Biological.
Advice
Incubator alternatives:
Here are tips for growing cultures without an incubator or a warm place such as a hot water system. Use a 40w incandescent globe, still available from Kmart and Big W but not Bunnings. Place petri dishes side by side and cover them with black plastic (bin liner). To keep a check on the temperature,…
Hydrogen Pop Test -Dangers:
Although most people have not had a problem with the hydrogen “pop” test, some schools have, with several cases of test tubes exploding and injuring students. It seems to be either inferior glassware, or students doing the pop test too close to the Hydrogen gas source, or a combination of both. It is recommended that…
Electro-magnets:
Question: Has anyone a good design for electro-magnets that actually works? It seems the designs in the texts are rather weak and not very effective. Answer: In order to have sufficient current passing through the wire, the wire must be rated to carry at least 3 amps. Wire of this thickness can cause the electromagnet…
Vitamin C content of fruit:
Question: Does anyone have information on how to test the Vitamin C content of different fruits? Answer: We do a simple practical using 5 different juices: freshly squeezed orange juice, bottled 100 percent cordial, lemon juice and boiled orange juice as comparisons. You could also use grapefruit but note that if you were using, for…
Sherbet:
Question: Does anyone have a recipe for sherbet which includes jelly crystals please? Answer: I tried many recipes, and the winners are: First prize: icing sugar 1 tablespoon Bicarb soda (Sodium hydrogen carbonate) quarter teaspoon citric acid quarter teaspoon jelly crystals 1 teaspoon Second prize: Bicarb soda 1 teaspoon icing sugar 10 teaspoons citric acid…
Science Snacks:
http://www.exploratorium.edu/snacks Science Snacks are miniature versions of some of the most popular exhibits at the Exploratorium, San Francisco.
Lemon Battery:
Question: Does anyone have any tips on how to make the lemon battery work? We are using Jacaranda Science Book 2, page 231. Answer: For best results with a lemon battery use BROAD pieces of zinc and copper (1-2cm wide, roughly polished with sandpaper). Use a high impedance meter (any digital multimeter) to monitor the…
Flame tests:
Question: Our text-book says to burn 2M solutions for flame tests, and I have tried solids too, but IT DOES NOT WORK! Can you please tell me what you do, and what actually works? Answer: Buy flame test bottles (atomisers) from Haines Educational. Use the following: All 0.5 M. Copper sulfate, sodium chloride, potassium chloride,…
Fingerprints-latent:
Question: Gentian Violet for fingerprinting is a banned substance now and is not procurable any more. Are there any alternatives? Answer: 1. On wood in silver nitrate. 2. Finger prints on filter paper in iodine chamber. Use a fume hood. Put fingerprints on filter paper and attach a paper clip and cotton thread to it,…