Learning Outcomes To re-cap on your photosynthesis knowledge from S2 To test a leaf for starch To write up this experiment

Re-cap – what do you remember? Think / Pair / Share Photosynthesis Re-cap – what do you remember? Think / Pair / Share What is photosynthesis? What is chlorophyll and what does it have to do with Photosynthesis? What things does a plant NEED for photosynthesis? What does a plant MAKE during photosynthesis? What is the photosynthesis word equation? What happens to the SIZE of the plant after photosynthesis and WHY? How can you prove that photosynthesis has taken place in a plant?

What is Photosynthesis? Green plants make their own food (glucose sugar) in a process called PHOTOSYNTHESIS. Iodine solution is used to test a leaf for starch. If starch is present it will change from brown to black. Photosynthesis song!

Testing for starch Safety glasses heat proof mat Ethanol boiling water turn off Bunsen burner boiling alcohol hot water iodine white tile Safety glasses heat proof mat Ethanol 250ml beaker Boiling tube Iodine Bunsen Burner Leaf sample Tripod white tile tweezers

Testing a leaf for Starch Aim: to test a leaf for starch in order to see if photosynthesis has taken place Method: draw a labelled diagram of each stage! Results: Colour of leaf before adding iodine solution: _____ Colour of leaf after adding iodine solution: _____ Conclusion:

Learning Outcomes To re-cap on your photosynthesis knowledge from S2 To carry out an experiment to prove plants require light for photosynthesis

chloroplasts A B F E C D

What is chlorophyll and what does it have to do with photosynthesis? Chlorophyll is found in chloroplasts Chlorophyll is only found in GREEN plants They absorb (take in) light energy.

What do plants need for photosynthesis? Plants need the following: Light energy (from the sun) Chlorophyll Carbon dioxide (from the air) Water (from the soil) What do plants make during photosynthesis? Plants make glucose sugar which they store as starch. They also produce oxygen.

Photosynthesis Word Equation Photosynthesis can be summarised as: Carbon dioxide + water oxygen + sugar (glucose) Light energy + Chlorophyll Raw materials Products How would you describe Photosynthesis using the word equation to help you? Photosynthesis is the process in which green plants use carbon dioxide from the air and water from the soil to produce sugar and oxygen

Photosynthesis Summary light energy carbon dioxide (from the air) chlorophyll glucose oxygen water (from the soil)

Algal Beads!! You must set this up as quickly as possible, because the beads need TIME to photosynthesise!

What is algae?

The experiment Collect 2 small bijoux bottles Rinse each bottle with a TINY volume of hydrogen carbonate indicator Carefully put 15 algae beads into each bottle Measure 5ml of hydrogen carbonate indicator using the syringe and add to each bottle Put the lids on and a black card cover to ONE bottle Place the 2 bottles in front of a lamp, making sure the tape faces away from the lamp Tidy up your equipment!

What is hydrogen carbonate indicator? Hydrogencarbonate indicator is very sensitive to changes in pH It contains dissolved carbon dioxide When there are equal concentrations of carbon dioxide in the indicator and in the air – it is orange/red When the concentration of decreases and there is less in the air– it is yellow When the concentration of increases and there is more in the air– it is purple So, because of these colour changes, we can see if the algae is photosynthesising!

Investigating photosynthesis in algae beads Aim: to investigate if a_____ beads require l_____ for p__________ Variables kept constant: list 3 for each bottle Method: draw a labelled diagram Results: Conclusion: Evaluation: how could you improve the experiment? Bottle containing algae beads Colour of hydrogen carbonate indicator No cover Black card cover

Learning Outcomes To re-cap on your photosynthesis knowledge from S2 To carry out an experiment to prove plants produce oxygen during photosynthesis

Cabomba!

What do you think these bubbles are?

The BUBBLER EXPERIMENT shows oxygen is being made!

COLLECT: Boiling tube Boiling tube stand Lamp Scissors Blue tac Dropper Bottle of sodium hydrogen carbonate (share with another pair) Cabomba strand (half) Health and Safety! The lamps get very hot! Be careful when touching them – you will burn yourself! Keep all liquid away from the lamp at all times Clear any spillages straightaway!

A piece of Cabomba equal to the length of a boiling tube. Place Cabomba in the boiling tube, stem end upwards

Fill boiling tube with 1% sodium hydrogencarbonate Activities that highlight relevance of the application of science to young people

Cut the Cabomba stem under the liquid 3-5. ‘Play’ with lamp

6. Squeeze the bulb of a 3 cm3 plastic dropper very tightly and extract fluid until dropper fills

7. Seal pipette by placing Blu-tack over tip

Full pipette essential! 8,9. Cut pipette at 3 cm3 mark, then top up any fluid lost Full pipette essential!

10, 11. Quickly invert the full pipette and place over the Cabomba tip

12. Irradiate

The effect of light intensity on the rate of photosynthesis in a cabomba plant Aim: to investigate… Method: draw a labelled diagram of the experiment set up Results & Conclusion: As the lamp moved closer to the cabomba and the light intensity increased/decreased, the rate of respiration/photosynthesis also decreased/increased. We know this because less/more carbon dioxide/oxygen bubbles were being produced by the cabomba. Evaluation: what could you do to improve the experiment? Explain what the word rate means (title)