By: Shen Yichen

Hu Qinxi

Soon Hao Jing

Terence Tim

Our ProjectOur ProjectHow does pH affect seed germination?

In this project, you will select chemicals that are acidic in nature (e.g. household

chemicals) and determine their effect on germinating green gram seedlings. The

effect of acidic solutions at different dilutions should be tried as well. Devise parameters

to measure the effect of the chemicals, such as the number of days to germinate.

Extrapolate your finding to the effect of acid rain on vegetation.

From Notes

HypothesisHypothesis

As the acidic level of the base As the acidic level of the base increases, the germination increases, the germination rate of seeds will decrease.rate of seeds will decrease.

Materials and EquipmentMaterials and Equipment

1. Red beans (1 pack)

2. Cotton wool (half a pack)

3. Dropper (x2)

4. pH Indicators (x20)

5. Petri Dishes (x5)

6. 500ml beakers (x2)

7. 100ml Measuring Cylinder

8. Hydrochloric Acid (1M HCl) (500ml)

9. Acetic Acid (1M CH3 COOH) (300ml)

10.Citric Acid (20%) (300ml)

What We DidWhat We DidTrial 1

We did some research on red beans(Azuki bean) and acids. Next we spread cotton wool in the Petri dish and used them as the base for growing the seeds. We had to use red beans instead of green ones because green beans germinate too quickly for us to observe the differences in the time of germination. We then diluted hydrochloric acid with water and watered the seeds in each Petri dish with the same amount of acids of different dilutions. We then checked for the number of days the seeds took to germinate.

Trial 2

We researched on the pH level of normal fertilizers, and tested the pH level of the tap water we used to water the plant. This time we used two different acids to see whether the types of acid will affect germination. Then we did the same thing to each Petri dish just like in Trial 1.

Results for Trial 1Results for Trial 1

pH pH levellevel

Time of Time of germinationgermination

Petri Petri Dish ADish A

22 6.37pm6.37pm

30 Mar30 Mar

Petri Petri Dish BDish B

33 7.03pm7.03pm

30 Mar30 Mar

Petri Petri Dish CDish C

44 6.45am6.45am

30 Mar30 Mar

ControControl (D) l (D)

6 to 76 to 7 6.40pm6.40pm

29 Mar29 Mar

Control

pH 2

Other Observation and ResearchOther Observation and Research

Observations

•Green mould like stuff start appearing on the cotton wool after a few days in the pH 2 and 3 dishes.

•The cotton wool in the control turned brownish

•The cotton wool in the pH 4 have some black spots on it

Research

The ideal pH level for soil is pH 6-7 because at this level, most of the nutrients and minerals are present in the soil.

The pH level for normal fertilisers however, is 5-6.

Citric pH 3

Acetic pH 3

pH LevelpH Level Time of Time of germinationgermination

Petri Petri dish Adish A

pH4pH4

(citric)(citric)6pm6pm

6 Apr6 Apr

Petri Petri dish Bdish B

pH3pH3

(citric)(citric)8pm8pm

7 Apr7 Apr

Petri Petri dish Cdish C

pH4pH4

(acetic)(acetic)7am7am

6 Apr6 Apr

Petri Petri dish Ddish D

pH3pH3

(acetic)(acetic)6am6am

9 Apr9 Apr

Control Control (E)(E)

pH6-7pH6-7

(Water)(Water)7am7am

9 Apr9 Apr

A little acid in the soil doesn’t really affect the rate of germination. However too much acid cause slow germination and even abnormal occurring (green stuff appearing). Also different acids have different effects on plants.

So, our hypothesis is partially correct.

Causes

•Volcanoes

•Natural biological process

•Power plants

•Motorcars

•Factories

Effect on forests include slow growth and causing damage to plants which in turn leave them more vulnerable to threats. They also cause mineral and nutrient loss from the soil.