Does an acidic pH affect plant growth?

Alfalfa (Medicago sativa)

Pea Plants Pisum sativum

Designing your experiment• Things to consider:– How many potted plant should you use?– How could you distinguish one pot from the other? One

group’s pots from the other groups?– How many seeds per pot?– Seed placement in pot– How much soil?– How much water per day? Water once a day or more?– Once your seeds germinate, how will you measure the

plants? What other things could you observe/record to indicate the heath of the plant?

Planting

1. Obtain all supplies needed.2. Make a label for each pot. Each label should have your group name.

Number each pot. 3. Fill each pot (at least 3) with soil. Record how much soil you started

with.4. Use your finger or a pen/pencil to poke a hole in the soil for each

seed.5. Place the seed in the soil hole. Cover the seed with soil. Make sure

to not plant the seeds on top of each other. Record how many seeds you planted.

6. Water your plants. Record how much water you used.7. Clean up your work area.8. Work out a watering schedule with your group members.9. Create a data collection chart in your notebook.

Date Day of experiment

Amount of solution Plant height

Number of leaves

Plant color

Other observations

9/19 Day 1 All plants given tap waterPlant 1 – 15 mLPlant 2 – 15 mLPlant 3 – 15 mL

None None None -Pots filled up ¾ with soil-Planted 3 tomato seeds in each pot in a triangular pattern

9/20 Day 2 All plants given tap waterPlant 1 – 18 mLPlant 2 – 18 mLPlant 3 – 18 mL

None None None Soil very dry so increased water to 18 mL

9/21 Day 3 All plants given tap waterPlant 1 – 18 mLPlant 2 – 18 mLPlant 3 – 18 mL

None None None No germination - Soil looks good, kept water at 18 mL

9/22 Day 4

Concluding Your Experiment

• Things to record:– Growth of each plant• Can compare control & experimental plants• Can compare growth rate before vinegar and after vinegar

– How many stems in each pot (Stem = Germinated seed)• Can compare to number of seeds planted

– Number of leaves per stem– Color of plant

Analyzing Your Data

• Did your results match your prediction/expectations?• What could have affected your results besides the vinegar?– Is the soil level the same as when you started?– Did you forget to water/vinegar?– Did you accidentally use vinegar on the control?

• Is there anything you could have done differently? Is there anything you would change to make your experiment better?

• How does your experiment relate to the original observed problem – acid rain? Based on your data, does acid rain have a negative affect on plant growth?