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9 Cards in this Set
- Front
- Back
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What did Greek scientists conclude from plants?
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They thought plants gain mass from soil minerals
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When did Greek scientists study plants and who studied it?
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Aristotle and around 350 BC
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What did the Greek scientists observe?
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They observed that the only thing touching the plants was soil, so they decided that plants must grow and gain mass by taking in minerals from the soil.
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Which scientist decided that plants gain mass by taking in water?
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Van Helmont
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When and what experiment did Van Helmont do?
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In the 1600s, Van Helmont set up an experiment. - He dried some soil, weighed it, and put it in a pot. - He planted a willow tree weighing 2.2kg in the soil. - He added rainwater to the pot whenever it got dry. - 5 years later Van Helmont removed the tree from the pot: 1. The tree weighed 76.7kg- so it had gained 74.5kg of mass. 2. He dried the soil and weighed it- its mass had changed very little. 3. Van Helmont concluded that because the weight of the tree and soil had changed so little, the tree must have gained mass from another source. |
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What did Priestley's experiments show ?
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The plants produce oxygen
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When and what experiment did priestly do?
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In the 1770s Joseph Priestly did an experiment : 1. He placed a burning candle in a sealed container and observed that the flame went out after a short time. The candle could not relight itself. 2. He then placed a burning candle and a living plant in the container. The flame went out after a short time but after a few weeks the candle could be relit again. |
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What did Priestly think happened?
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He decided that the burning candle used up something in the container- so this made the flame go out. He also decided that the living plant "restored air" so the candle could burn again.
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Did Priestly do another experiment?
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Yes, he did the same experiment again but with a mouse instead of a candle.
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