A CTIVITY 81: A PRODUCER ’ S SOURCE OF ENERGY Challenge  How do scientist’s study the role of light in photosynthesis? Important Vocabulary: Photosynthesis Producer Elodea

G ETTING S TARTED : T ALKING D RAWING #1 How do producers, such as phytoplankton and plants, produce food?

R EAD I NTRODUCTION ON P AGE E-50. What evidence must have been required to discover the process of photosynthesis? Evidence for water? Evidence for Light? Evidence for sugar being produced? Evidence for use of Carbon dioxide and production of Oxygen? These ideas were difficult for scientists too!! They had to investigate the uptake of CO 2 and production of Oxygen

Is light necessary for photosynthesis? What evidence do you have for your ideas? How do you think you could collect evidence to support or disprove these ideas?

P HOTOSYNTHESIS – W ORD E QUATION *C OPY INTO YOUR JOURNAL * sunlight Carbon + Water  Food + Oxygen Dioxide CO 2 + H 2 O (yield) O 2 What actually is the food? sunlight 6 CO H 2 O  C 6 H 12 O 6 + 6O 2 GLUCOSE (FOOD!)

W HAT IS BTB? – R ECORD IN YOUR NOTEBOOK ! BTB stands for bromothymol Blue. BTB is a carbon dioxide indicator

Initial BTB color Final BTB colorColor change show presence of what gas? Person exhaled into BTB solution DATA TABLE 1: Results with BTB

A FTER YOUR H YPOTHESIS Look at vials L= Light C= Control D= Dark Predictions: L= Will photosynthesize and the water will turn blue C = Will remain the same D= Will remain the same (No photosynthesis)

S HOULD LOOK LIKE … W HICH IS WHICH ?

R ECORDING O BSERVATIONS - PART B Exposed to LightIn the Dark (Aluminum) Initial Final

A NALYSIS Q UESTIONS Discuss #s 1, 2 and 4 with your tables and record the answers in your journal.