Kōkiri Learn

Week 4 of 5

Fuel from light, energy from fuel: photosynthesis and respiration

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Session 1 · VOICE: Investigate

Floating leaf discs

  1. 10 minPlan: what could change how fast leaf discs photosynthesise? Choose one variable (light distance, light colour or baking soda amount). Keep everything else the same.
  2. 30 minRun the test: sink the discs with a syringe, put cups at different distances from a lamp, count floating discs every minute for 20 minutes.
  3. 10 minSet up the yeast balloon test for tomorrow: same yeast and water, different amounts of sugar or different water temperatures, and one bottle with no sugar.

Session 2 · VOICE: Create Conclusions

What were the cells doing?

  1. 15 minMeasure the yeast balloons with a string around the widest part. Add the class leaf-disc data to one graph.
  2. 15 minWrite a claim, the evidence (your numbers) and your reasoning (what the chloroplasts or mitochondria were doing).
  3. 15 minDraw the big flow chart: sunlight, water and carbon dioxide into a chloroplast, sugar and oxygen out; sugar and oxygen into a mitochondrion, energy, water and carbon dioxide out. Show diffusion moving the gases.
  4. 5 minTeacher demo or images: a leaf with a foil patch turns blue-black with iodine everywhere except under the foil. What does that tell us?

Getting started

Use the results table with the minutes already filled in, and the flow chart with arrows drawn and words to place.

Stretch

Calculate the time for half the discs to float at each lamp distance and plot it. What shape is the line?

Checkpoint

Every student has a claim backed by their own data and a flow chart that links photosynthesis and respiration.

Activities for this week

Useful this week