Science Buddies: "Ask an Expert"

I'm doing an experiment that tests whether water from boiling lentils, rice, broccoli, etc, has a reasonable effect on plants - is that water better than normal water.
Do you think this is a good experiment?

Hi Amy,

What is your objective with your science project? Or, what question are you trying to answer? Is this related to your earthworm project? Usually the best science projects are those that identify a problem that can be solved by doing a controlled experiment. Your topic here could be either asking a question about how to grow plants better or to identify the best use of water leftover from cooking food.

Good science fair projects are always based on scientific principles. So for this topic you would need to do background reading and learn about the nutritional requirements of plants so you can design an experiment that would make sense. You would also need to measure or find information about the potential nutrients available in the leftover cooking water and formulate a hypothesis that you could test with your experiment. And, you need a quantitative method for measuring plant growth. '

The project guide on the Science Buddies website is really an excellent tool to use to guide you through the process of doing your project:

https://www.sciencebuddies.org/science- ... ndex.shtml

Have you already started your project? If not, I could provide some advice that you could use to develop your topic and design an experiment. Please let me know when your project is due. However, if you have already started your experiment and are working on a deadline, let me know exactly what you are doing and I’ll provide advice for incorporating some more science into the project.

Donna Hardy

No, this isn't to do with my earthworm project. It's just simply to test whether by-product water would be a reasonable alternative to fertiliser, and whether it is better than normal water. It also encourages water recycling. I'm using water from lentils (high protein), rice (high-carb), broccoli (high in vitamins/chlorophyll) , eggs (calcium) and tea (high-caffeine) as well as a control (plain water).
I have started growing the plants for the experiment, and have watered them once so far.
It's due about midway into September. If it does not produce viable results, I will be conducting an experiment with worms castings vs. fertiliser (I can use the same plants for this).
Thanks!

Hi,

Excellent. This is a project in plant nutrition. For your background information, you will want to include information on nutritional requirements of plants and the basic function of each element in plant growth. Here is a website that includes a list of plant nutrients:

http://www.atlanticfec.com/1-2.htm

Next, you need to find out what nutrients are present in the lentil, rice, broccoli, egg and tea. The water is a good control to use. You might want to focus on the nitrogen, potassium, and phosphorous content of your samples. Or, you could include the micronutrients needed by plants like zinc, calcium, magnesium, or iron.

Here is a website that includes the chemical composition of lentils. You are correct; this sample contains nitrogen.

http://pubs.acs.org/doi/abs/10.1021/jf00092a007


Here’s information on the nutritional composition of broccoli, including protein and potassium and phosphorous.

http://www.whfoods.com/genpage.php?tnam ... ice&dbid=9

Here’s the content of brown rice:

http://en.wikipedia.org/wiki/Brown_rice


Here is information on eggs.

http://en.wikipedia.org/wiki/Egg_yolk

http://en.wikipedia.org/wiki/Egg_white

Here is the composition of tea:

http://www.fmltea.com/Teainfo/tea-chemistry%20.htm

Here is the molecular structure of caffeine. Please note that this molecule contains nitrogen, oxygen, carbon, and hydrogen. Do you know if plants absorb caffeine directly? How would a plant utilize the nitrogen and other elements in this molecule?

http://en.wikipedia.org/wiki/Caffeine

I recommend that you make a table that includes the elemental composition of each of your samples. You have selected very complex samples to work with, so this will be challenging.

Next, please let me know what type of plants you are working with, how many plants in each group you are using? How are you controlling all parameters, except for the nutrient solutions? How are you measuring plant growth? When did you start your experiment? How often are you measuring results?

What is your hypothesis?

Donna Hardy

Thanks!
I have about 20 chives seeds and 4 silverbeet (spinach) seeds in each pot and I have 12 pots - 2 for each type of water.
My hypothesis...I'm not sure yet. Which one do you think would boost growth the most? I'm thinking the broccoli or lentils?

Hi again I was thinking, after I grow the seedlings, can I change my experiment?
Perhaps organic vs. inorganic fertiliser?
Organic:
- worm 'tea'
- cow manure
- compost
Inorganic:
- liquid fertiliser
- normal fertiliser
- slow-release fertiliser
Control:
- just water in normal soil

As you can see, the liquid fertiliser corresponds with the worm 'tea', the manure with the normal and the slow-release with the compost.

The experiment will be testing whether chemical (inorganic) fertilisers are really better than organic. My hypothesis is that the chemical fertilisers will work better.

Hi,

Have you started your experiment? If not, then you could go ahead and change the experiment, although it seems like you have a lot of independent variables. If you have started the experiment, then I would recommend not changing at this time. You want to make sure you have enough time to grow the plants and observe any difference in the growth. It’s not a good idea to change variables in the middle of an experiment.


Donna Hardy

I'm planting the seeds again cause I didn't have enough.

Hi,

If you run out of seeds again, then reduce the number of variables and keep the number of plants seeds for each test group as large as possible. You need to investigate the chemical composition of each of the fertilizers you use to give you a basis for comparing results.

Donna Hardy

I don't think I'll run out again
Ok! My dad says that putting compost in pots is very concentrated and could kill the plants.
So I'll do:
Organic:
- worm 'tea'
- cow manure
- egg shells (crushed and embedded in soil)
Inorganic:
- liquid fertiliser
- normal fertiliser
- slow-release fertiliser (every time you water it, some of the beads dissolve into the soil)
Control:
- just water in normal soil

I'll have two pots of each with hopefully around 5-10 plants in each pot.

Hi,

This sounds liks a good experiment, and everything is the same except the fertilizer used. Go ahead and set this up and let me know what happens. I am very interested in knowing what happens. When is your project due?


Donna Hardy

Mid-September. If the plants don't grow fast enough, I will buy seedlings.

Hi,

That's good. This will give you almost 4 weeks to collect data and a few days to complete the write up for the display board. You can go ahead now and start writing up your display board; you can write all of the sections except the results and conclusion now. Here is the information on the science buddies website for preparing a display board:

https://www.sciencebuddies.org/science- ... oard.shtml

I recommend that you wait until the seed germinate and start growing before you start fertilizing. Adding too much nitrogen when the plants are very small could allow fungi to grow that will kill the seedlings.

Donna Hardy

Do my title and hypothesis sound ok?

Which fertiliser is the best plant height energiser?
Hypothesis: The chemical fertilisers will produce taller plants, but the organic fertilisers will produce plants of a better quality.

Hi,

Yes, I like you title. Questions are always a good way to present the purpose of a science fair project and it implies that the question will be answered by the experiment. Asking a question encourages the reader to continue looking at the project to find out what the answer will be.

The first part of the hypothesis is good because it is a statement related to the question and refers to plant height, which is what you will measure. The statement about the quality of the plants is unclear unless you define “quality.” Will the organic fertilizers, do you think the plants will have more leaves, larger leaves, greener leaves, more roots, or some other parameter that you can measure? If you make a statement about what you think the results will be with organic fertilizers, then your experiment must include quantitative data that you can use to calculate the answer.

Please tell me exactly what you are measuring. If you are only measuring plant height, then your hypothesis should be “The chemical (or organic) fertilizers will produce taller plants.” If you are measuring plant height and counting the number of leaves, then you could say ”The chemical fertilizers will produce taller plants, but the organic fertilizers will produce plants with more leaves.” But then you would then need to change your question to include the second parameter. Does this help?

In the next section you will need to explain why you think your hypothesis will be correct based on your reading from scientific sources. Why do you think chemical fertilizers will result in increased plant height compared to organic fertilizers?

Donna Hardy

Ok thank you!
I will observe the roots on the last day of the experiment. I'm just wondering, are longer roots a good or bad thing?

Hi Amy,

In general, bigger is better with plant growth, since main objective in growing crop plants is the harvest of the edible plant, and taller plants with longer roots would imply that the plants would reach maturity earlier and the plants would be more productive.

How is your experiment going? Have the chive and spinach seeds germinated yet?

Donna Hardy