(Algal balls) Investigating photosynthesis

• What are algal balls

  Jelly balls containing pondweed which will photosynthesise
• As the algal balls photosynthesise what gas do they use up 


  CO2 in the water
• What can we use to monitor the ph change 


  Colour changing indicator (forms carbonic acid)
• What colour changing indicator will we be using in the algal balls practical 


  Hydrogen carbonate
• Describe the link between CO2 and how alkaline a solution is 


  CO2=acidic gas -> the less CO2 -> the more alkaline
• What does the solution becoming more alkaline mean


  Higher pH -> lower levels of CO2 -> more photosynthesis has happened
• What can you conclude from the algal ball practical 


  The closer the balls to light source -> higher rate of photosynthesis -> higher pH -> lower level of CO2
• What are the independent variables in the algal ball practical

  The distance from the light source
• What is the control variable in the algal ball practical



  An extra bottle of algal bottle to make sure there's the same amount of photosynthesis
• What can you use to work out the starting pH for each bottle

  pH chart
• What is a heat filter 


  Beaker filled with water
• Why is a heat filter needed 


  To remove the heat energy from the lamp/absorb it
• What is the dependent variable in the algal ball practical



  The change in pH