Excerpt from the “Banned and Restricted” List Hydrogen balloon Restricted to a small balloon inflated < 200mm. Highly flammable and extremely loud noise. Can cause burns from molten rubber, fire and damage to ear drums. Highly flammable 2.1 Use helium balloons as they are better quality Teacher demo only Balloon diameter below 20 cm. Check…
Advice
Agar Diffusion Practical suggestions (collated)
Dabco trays (see below), work well because of the use of the divider. Dabco Unitray with insert – Haines Educational Use Dabco trays as a mould for the agar and then just cut it into size. Use bromothymol blue and vinegar. I can send you the practical sheet and tech notes. Unitrays with the divider…
Saliva substitute:
Use 1-3% diatase, which is free from reducing sugars,or 1% bacterial amylase. These chemicals are available from Southern Biological.
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,…
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,…