You need: a sachet of dry yeast, two spoons of sugar, warm (not hot) water, a small plastic bottle and a balloon. What happens: after 20–30 minutes the mixture froths and the balloon slowly blows up. Why: yeast is a tiny living fungus. In warm water it feeds on the sugar and gives out carbon dioxide gas, which fills the balloon. This is how yeast makes bread dough rise. Cold water slows it down and very hot water kills it.
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🏁 Lesson 16 test
20 questions. Check each answer, then go to the next one. Get 16 or more right to pass.
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