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How Different Liquids Affect the Growth

of Mung Beans:

A Science Fair Production

Emilie Beaupain

2/24/21

Science

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Research Question -

In this science fair project, I researched which liquids are best for the growth of

mung beans. I always wondered if different liquids could boost the growth of plants to

increase their harvest. Now, I tested that out to see which of the liquids, coffee-water,

sugar-water, salt-water, garlic-water, lemon-water, or regular water, would of these liquids

would make the mung beans grow the most.

Hypothesis -

If I add lemon water, garlic water, coffee water, sugar water, salt water,

(independent variables) and regular tap water to mung beans, then the sugar water will

make the beans grow the fastest, with the regular water coming in second because of

the following:

1) Salt has high amounts of sodium and chloride which is toxic to plants, and

also prevents water from coming up through the roots.

2) Coffee has nutrients but will make it harder for the plant to start growing as

a seed. Coffee also changes the pH of the soil.

3) Garlic water has no negative effects (unless over-used) and barely any

positive effects.

4) Lemon water is acidic and can lower the pH, which is not good for mung

beans, and it can burn the leaves if they are touched by the solution.

5) Sugar water will grow the most because it can give more energy to the plant

to help it grow faster.

6) Regular water will grow second-fastest because it will help the plant grow

at a normal pace.

If my hypothesis is correct, then people can increase their harvest of mung beans

by using sugar water to grow the mung beans the fastest. If my hypothesis is correct,

there is still the question of whether it affects the taste of the bean. Also, will it mold? If

so, there might be another liquid that elicits the same growth as the sugar but doesn’t

mold, which makes it safer to eat.

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Research -

First, I researched how sugar water could affect plants. According to a Garden

Tools & Instruments article, How Does Sugar Water Affect a Plant's Growth?, sugar

water can give more energy to the plant to help it grow faster because when the plant

drinks sugar water, the plant's porous plant cell membranes (plant membranes with

pores/very tiny holes) let in water because of their high sugar content. The plant stores

sugar for roots so the roots can grow, so it is believed that adding a bit of sugar gives

roots extra food to grow faster. I think that adding sugar to tap water will make the beans

absorb additional amounts of sugar and use that extra energy to grow the fastest.

Second, I researched how the pH level of different liquids would affect plants.

Different liquids in the soil can change the pH of the soil, can affect or give different

nutrients going into the plant, and can deprive the plant of nutrients. Coffee Cup

Science’s article, Growing Plants with Caffeine - our Ultimate Guide, says that

watering a plant with coffee can stunt and distort the growth of a mung bean and may

make the plant stop growing entirely because the chemicals in coffee may alter the pH of

the soil. Salt can “affect the germination of mung bean plants'' because a...

“high concentration of salt in the soil can interfere with a plant's ability to take

up and hold water in its roots. High amounts of sodium and chloride are toxic to

plants as well. Saline soil can also reduce the amount of micronutrients that are

available, and this leads to mineral deficiencies.”

In other words, this quote states that salt will affect the nutrients and beneficial microbes,

leading to a plant that won’t grow.

Furthermore, as stated by Garden Guides’ website Why Does Salt Affect the

Germination of Mung Bean Seeds?, lemon juice can alter the pH because of the high

acidity, and lemon juice on the leaves can “cause them to shrivel, compromising the

plant's ability to perform photosynthesis.” Lemon juice will be negative for plants except

for those plants that like acidity.

On the other hand, garlic is not harmful to plants and doesn’t affect the plant’s

growth or vigor, according to Dengarden’s post How to Make and Use Garlic Water

Pesticide for Plants. “While the solution effectively eliminates pesky garden infestations,

it can also negatively affect beneficial soil microbes if used too often.”

To summarize, this research shows that almost all the liquids except sugar water

and tap water will have a negative effect on the mung beans, so the mung beans watered

with tap water and sugar water will produce the most growth.

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Procedure -

1. Prepare habitat by placing half of a paper towel, folded into four layers, at

the bottom of each cup

2. Prepare all liquids by adding 1/16 cup of each IV (sugar, salt, etc.) and add

¼ cup of water.

3. Let sugar and salt dissolve into the water, coffee cool, and garlic steep for

1 hour before watering ¼ cup of each liquid into the adjacent cup.

4. Take pictures each night after watering and repeat the process for 6 days

Variables -

Independent variables (the types of liquids I watered my mung beans with):

lemon water, garlic water, coffee water, sugar water, salt water, and regular water

Dependent variable: the growth, measured with a ruler

Control variables: the habitat and the mung beans.

Results -

For my results in experiment one, the mung beans didn't grow as much compared

to the mung beans in experiment two.

I did experiment 1, and the following happened: In experiment one, the coffee was

the longest and the mung beans watered with tap was second. Nothing molded, to my

surprise, but nothing grew too much either.

I did experiment 2, and the following happened: The mung beans watered with tap

water in experiment 2 grew much more than the mung beans watered with tap water in

experiment one. However, the beans watered with sugar grew about the same amount in

both experiments. The lemon-watered mung beans in the first experiment were equal to

the one in the second experiment, except for the fact that in the second experiment there

was lots of fuzzy blue and black mold on the beans. In experiment 2, it was the tap that

was longest, with the mung beans watered with coffee in second. The mung beans

watered with garlic came in third both in experiment 1, and experiment two.

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Trial 1: Rate of Growth of Mung Beans in Different Solutions

(mm)

Beginning Length Ending Length Total Growth

Coffee Water 4 11 7

Salt Water 4 4 0

Sugar Water 4 4 0

Garlic Water 4 6 2

Lemon Water 4 5 1

Water (Control) 4 10 6

Trial 2: Rate of Growth of Mung Beans in Different Solutions

(mm)

Beginning Length Ending Length Total Growth

Coffee Water 4 8 4

Salt Water 4 4 0

Sugar Water 4 4 0

Garlic Water 4 6 2

Lemon Water 4 4 0

Water (Control) 4 63 59

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Average Growth of Mung Beans in Different Solutions

(mm)

Ending Length :

Trial 1

Ending Length

: Trial 2

Average

Growth

Average

Growth

Coffee

Water 7 4 5.5

Coffee

Water 5.5

Salt Water 0 0 0 Salt Water 0

Sugar Water 0 0 0 Sugar Water 0

Garlic Water 2 2 2 Garlic Water 2

Lemon

Water 1 0 0.5

Lemon

Water 0.5

Water

(Control) 6 59 32.5

Water

(Control) 32.5

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Conclusions -

My hypothesis turned out to be wrong: If I add lemon water, garlic water, coffee

water, sugar water, salt water, and regular tap water to mung bean plants, then the plants

watered with sugar water will grow the fastest, with plants watered with regular water

coming in second. Instead, ….. I think it was wrong because mung beans don’t have

roots, so the extra boost from the sugar for the roots is wasted. The plants watered with

tap water grew the most, most likely because, without the coffee, salt, sugar, garlic, or

lemon juice, it was not held back by those liquids’ negative effects.

One mystery is why the coffee water grew fast in experiment 1 but not in

experiment two. Next time, I would research this more to see if I can manipulate the

positive effects of the coffee. Another thing to research is how to prevent the mold from

growing on the mung beans when you water them with different liquids. This will make it

safe to eat and if it is safe to eat then I can experiment with the taste of the plants that are

watered with different liquids.

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Appendix -

1st Experiment - Photographs

Coffee longest

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Tap second

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Garlic third

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Lemon just sprouting, bleached

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Sugar not sprouted yet, soon though

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Salt still dehydrated and small

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2nd Experiment - Photographs

Coffee sprout grows almost 2 cm

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Salt same, doesn’t sprout or change in appearance

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Sugar same, enlarged but not sprouted

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Garlic past sprouting, sprouts about 1/4 cm

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Lemon the same and fuzzy mold white

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Tap is giant

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Works Cited:

CK. Growing plants with caffeine - our ultimate guide. Coffee Cup Science.

(2019). Retrieved From:

https://coffeecupscience.net/caffeinefuelledseedlings/

Garden tools and Instruments. How Does Sugar Water Affect a Plant's

Growth?. (2018). Retrieved From:

https://www.youtube.com/watch?v=PJpRE3B-BKo

Harris. Rob. Can I Feed Lemon Juice to Plants?. SFGate. Retrieved From:

https://homeguides.sfgate.com/can-feed-lemon-juice-plants-104940.html

J. Lang Wood. Why Does Salt Affect the Germination of Mung Bean

Seeds?. Garden Guides. (2017). Retrieved

From:https://www.gardenguides.com/13406185-why-does-salt-affect-the-

germination-of-mung-bean-seeds.html

Zach. How to Make and Use Garlic Water Pesticide for Plants. Dengarden.

(2019). Retrieved From: https://dengarden.com/gardening/Using-Garlic-

Water-for-Plants