light

• independent variable - light intensity
• dependent variable - height of the seedlings
• place cotton wool into three petri dishes and then soak them with equal volumes of water
• control variable - volume of water
• 2. place 10 of given seeds in each dish
• 3. leave the dishes in a warm place and allow seeds to germinate
• 4. water seeds everyday with same volume of water. after a few days the seeds will germinate
• 5. make sure there is equal number of germinated seeds in each dish,if not remove some
• 6. use a ruler to measure the height of each seedling. hold stem to make sure they are straight, do not damage them
• 7. place each dish in different different conditions. one placed in full sunlight (a bright windowsill) one in partial light (back of a lab) and the other placed in darkness (a cupboard)
• 8. measure the height of each seedling for 5 days and record results in a table. calculate mean seedling height for each day and a diagram to show effect of different light intensity on each seedling.