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In the late 1700s, the Dutchman, Jan Ingen-Housz, discovered that plants only gave out oxygen when they were in light. He also showed that only the green parts of plants give out oxygen. Do you remember what the green-coloured matter in plants is called? Well done if you remembered that it is called chlorophyll. Jean Senebier's experimentAt the end of the eighteenth century, a Swiss minister named Jean Senebier worked out that another gas, carbon dioxide, is involved in photosynthesis. He also reasoned that the larger the plant the more carbon there was present. Carbon can be seen when plants are burnt. The bigger the tree, the more charcoal (carbon) Senebier produced. Senebier showed that the carbon came from the intake of carbon dioxide. Carry out the activity to summarise what these experiments tell us about plants. Summary Complete this summary using these words: controlled oxygen sunlight carbon dioxide food variables make/produce water tests Summary· Plants grow without
· Plants need
· Plants give out
· Animals need the oxygen that plants
· Photosynthesis occurs when plants are in
· Plants take in
·
in an experiment. · An experiment should be planned so that it
one variable only. · In a
is changed; the other variables are kept the same. In this Exercise , you'll test your understanding of controlled experiments and variables, and your skill at presenting information as drawings. Go to Exercise.
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End of Lesson 7 - Photosynthesis |
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