Joseph Priestley’s Experiments from the 1700s

Candle-Burning Experiment Joseph Priestley’s Candle-Burning Experiment Part 1 Priestley lit a candle. He then placed a glass jar over it… …and watched as the flame gradually died out.

Candle-Burning Experiment Joseph Priestley’s Candle-Burning Experiment Part 1 Priestley lit a candle. He then placed a glass jar over it… …and watched as the flame gradually died out.

Candle-Burning Experiment Joseph Priestley’s Candle-Burning Experiment Priestley reasoned that something in the air was necessary to keep the flame burning.

Candle-Burning Experiment: Joseph Priestley’s Candle-Burning Experiment: Part 2 Priestley then placed fresh mint leaves underneath the jar and allowed the entire setup to sit for a few days.

Candle-Burning Experiment A few days passed… Joseph Priestley’s Candle-Burning Experiment

Candle-Burning Experiment Joseph Priestley’s Candle-Burning Experiment After a few days, Priestley found that he could relight the candle and it would burn for a while.

Candle-Burning Experiment Joseph Priestley’s Candle-Burning Experiment After a few days, Priestley found that he could relight the candle and it would burn for a while.

Candle-Burning Experiment Joseph Priestley’s Candle-Burning Experiment Priestley concluded that the plant had produced the substance required for burning.

Candle-Burning Experiment Joseph Priestley’s Candle-Burning Experiment What substance was consumed as the candle burned the first time? water oxygen glucose carbon dioxide OXYGEN

Candle-Burning Experiment Joseph Priestley’s Candle-Burning Experiment What must have been added to the jar to enable the candle to burn the second time? water oxygen glucose carbon dioxide OXYGEN

Candle-Burning Experiment Joseph Priestley’s Candle-Burning Experiment Where did this oxygen come from? the jar the pot the plant the air outside the jar THE PLANT

Candle-Burning Experiment Joseph Priestley’s Candle-Burning Experiment What do you think would happen if Priestley had put the plant and candle back in the jar for a few days then once again tried to light the candle? the plant would die the plant would light on fire the candle would light again the candle would not light again C

Candle-Burning Experiment Joseph Priestley’s Candle-Burning Experiment Suppose Priestley had put the plant and jar into a dark closet for a few days. Do you think the candle would have lit again? yes no NO

Candle-Burning Experiment Joseph Priestley’s Candle-Burning Experiment What does this tell you about plants and oxygen? D plants do not need oxygen plants produce oxygen all the time plants produce as much oxygen as they need plants produce oxygen in the presence of light

Joseph Priestley’s Other Experiments In another experiment, Priestley put a mouse under the jar and waited to see what would happen.

Joseph Priestley’s Other Experiments In another experiment, Priestley put a mouse under the jar and waited to see what would happen. Sadly, the mouse eventually died.

Joseph Priestley’s Other Experiments Later, Priestley put a mouse under the jar with fresh mint leaves and waited to see what would happen. To his surprise, both the mouse and plant survived for quite some time.

OXYGEN Joseph Priestley’s Other Experiments What important substance was produced by the plant? water oxygen carbon dioxide none of the above OXYGEN

CARBON DIOXIDE Joseph Priestley’s Other Experiments What important substance was produced by the mouse? CARBON DIOXIDE water oxygen carbon dioxide none of the above

SUBSTANCE THAT THE OTHER NEEDED Joseph Priestley’s Other Experiments Why were both the plant and the mouse able to survive under the jar? EACH ONE PRODUCED THE SUBSTANCE THAT THE OTHER NEEDED

Figure 7-3 The products of photosynthesis are the chemical ingredients for cellular respiration, while the products of cellular respiration are the chemical ingredients for photosynthesis.