Ireallyneedyourhelp
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Measurement Problems

Postby Ireallyneedyourhelp » Fri Oct 12, 2018 3:44 pm

Hello Expert! I'm doing a science fair project about the effect of different types of smells found in the city on the health of plants. The problem is that I don"t know if these smells (gasoline, paint, crushed flowers, none) would actually affect the plant by showing any visible differences. For example, if the height of the plant exposed to gasoline was dramatically smaller than the constant ( no unique smell ). I know that smells probably wont affect the plants that dramatically so I'm scared that when I'm ready to collect my data at the end of my experiment, there would be no visible differences that I could measure. So is there another way that I could measure the effect of the different types of smells had on the plant? Thank you for your time spent on reading this paragraph, and I hope you answer soon.

Sincerely,
8th grade student
:)

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Re: Measurement Problems

Postby SciB » Sat Oct 13, 2018 11:53 am

Hi and welcome to Scibuddies! I'm happy to try and help you.

I really like your idea about plants being affected by chemicals in the air. If you smell gasoline, that means the molecules of gasoline have gotten in your nose and affected the nasal cells that respond to odor chemicals. Plants don't have 'noses' like us but they can be affected by chemicals in the air--but more particularly by substances in the soil where their roots are.

I have read that there are some house plants that can be damaged or even killed by fumes from an oil-burning furnace, so yes, it is possible to do a project like you are proposing. The first problem I would have would be selecting the plants for the test. They have to be pretty much identical as to species, age, size and leafage. The next problem is how to expose a plant to chemical fumes. I would probably get several large, long clear plastic storage bins big enough for three plants to be placed in side by side. You need one bin for each odor test including the control.

Place the plants inside the bin, add the chemical or whatever on paper towels and close the lid. I would NOT use gasoline as it is extremely flammable. Heating oil or diesel fuel is not as flammable as gasoline but you still need to be very careful with it.
You want to use three plants for each test so you can average the measurements to get a more accurate result. I don't know for how long you need to expose the plants to the odors, but I would guess 3 or 4 hours would do it.

Now as to the last problem--what to measure. There are several possibilities with plants. You can record the height, you can weigh the plant in its pot [weigh the pots before putting the plants in and write the weight on the outside of the pot], you can count leaves or try to estimate their total surface area, and then you can record your observations as to discoloration or browning of the leaves, leaves dropping off, affects on flowering or anything else that you see that looks different from the untreated control plants.

You need to take lots of photos, naturally, and record everything in your lab book.

I hope this helps. I'm sure you will have more questions, so post back after you decide what you want to do for your project.

Good luck!

Sybee

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Re: Measurement Problems

Postby Ireallyneedyourhelp » Tue Oct 16, 2018 7:21 pm

Thanks for your response Sybee!

I put together a procedure for my experiment and I wanted you to read it to see if I should change anything.

1. Gather materials; 23 used water bottles, a bag of soil, 30 bush bean seeds, 23 cotton balls, scents chosen in the experiment in a liquid form(paint + water, diesel fuel, crushed flowers + water), wooden stick, black sharpie.
2. Hot glue one cotton ball to the underside of each cap.
3. With the black sharpie, label the six water bottles and caps by their contents. For example, label six “paint”, another six “diesel fuel”, another six “flowers” and the remaining five “none”. To avoid confusion later group the water bottles according to their labels.
4. Pour a cup of each of the scents in their liquid forms into three water bottles that are labeled with the same scent and tightly screw the caps on.
5. Pour a cup of soil into each of the other remaining water bottles.
6. Drop two bush bean seeds into each of the water bottles that contain the soil.
7. Push each seed down an inch into the soil, using the wooden stick.
8. Fill the spraying bottle with water, and spray water on the soil two times for each water bottle.
9. Turn over the water bottle that contains diesel fuel. The cotton ball on the inside of the water bottle should now be soaked with the smell.
10. Unscrew the cap and screw it onto a water bottle that has “diesel fuel” written on it.
11. Take another cap that is labeled “diesel fuel” and repeat steps 11-12.
12. Screw the remaining cap onto the water bottle that contains the diesel fuel.
13. Repeat steps 11-12 but for the other scents. The water bottles labeled “none” will have no unique scent so screw their caps back on.
14. Repeat steps 8-13 every four days for three weeks.

Thanks,
8th grade student

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Re: Measurement Problems

Postby SciB » Thu Oct 18, 2018 6:53 pm

Wow! You really put some thought into this project! Everyone should be as careful as you in outlining every step of the procedure beforehand so you can check for problems before you start.

I read through the steps of your experiment and there are a couple of things I would suggest:

1. Two 'sprays' of water for each cup of soil may not be enough. If the soil is too dry the seeds will not germinate. It should be moist but not wet. You could experiment with a cup of soil in a bowl that you could spray with water and then squeeze with your fingers to feel if it is damp enough. I can't explain 'damp enough'--its something you learn from gardening experience.

2. Bush bean seeds may germinate better if they are soaked overnight before planting (https://www.planetnatural.com/soak-seeds/). Also, the soil needs to be kept fairly warm--75-85F (24-30C) for good germination. I would suggest, if you have time, to test the germination of your seeds before you set up to do the actual experiment. If they fail to sprout then you have done all that work for nothing. Take three seeds, soak them overnight for several hours or overnight, then put them between two damp paper towels, fold them up and put them in a warm place. After a couple of days you should see roots and shoots sprouting from each seed.

3. You don't say what you are measuring as your dependent variable but I would guess that you are planning to weigh the bottles before the experiment and at the end--is that right? Bean plants can get pretty large, pretty fast and most water bottles I have are small. I understand why you want to use them and it is a good way to expose the plants to the odorant but I am afraid you may not be giving the plants enough room to put out leaves. Since you only plan to run the test for three weeks, though, it may be ok to use water bottles.

4. Be sure you take lots of before and after photos.

Good luck!

Sybee

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Re: Measurement Problems

Postby Ireallyneedyourhelp » Fri Oct 19, 2018 3:10 pm

Thanks for your suggestions!

I will probably try soaking the seeds before planting them and also measuring the mass of the water bottle before and after. Would four "sprays" every four days be enough? Also if you don't mind I would also really appreciate it if you could read through my introduction paragraph, and give me some feedback about it.


Plants undergo photosynthesis to feed themselves. Photosynthesis requires carbon dioxide, which they extract from their surroundings using small pores on the underside of leaves called stomata. Studies were done by Wolverton, Mcdonald, Watkins (1984) also suggested that plants can absorb harmful chemicals, such as formaldehyde, using the same mechanisms. Because of this ability that plants have, people use them to purify the air indoors (Claudio, 2011). The researcher wondered if the plant health are affected by them absorbing these chemicals. This idea prompted her to conduct an experiment that would test the effect of different types of scents that can be found in the city on the health of a bush bean plant(Phaseolus vulgaris). The data the researcher would collect could help agriculturists know which scents an environment contains are suitable for planting.

According to Consuelo and De Morales (2015), a plant’s sensory perception includes the ability to sense volatile ethylene hormones. These volatile are produced by all known plant species, (Yang and Hoffman, 1984), and are released when plants are attacked. This causes other plants nearby to sense danger and can put up their defense mechanisms before they too are attacked. For example, Heil and Silva Bueno (2007) found that lima bean leaves produced more extrafloral nectar when they are exposed to damaged leaves on the same shoot, this serves to recruit predators, and prepares for additional defense mechanisms. The researcher concluded that if the bush bean plants receive these volatile signals from crushed flowers they would be on constant alert all the time, therefore, growing the best.

Not only are plants able to sense volatile ethylene hormones, but they can also absorb volatile organic compounds(VOCs) as well (Yang, Pennisi, Son, Kays, 2009). VOCs can be emitted as gases from paints, and paints thinners and are also toxic to humans (Fortmann, Roache, Chang, Guo, 1998). The researcher wanted to know if the bush bean plants are affected by paints containing VOCs like humans are.

Plants can absorb toxic chemicals from the air, including VOCs such as benzene. (Orwell, Wood, Tarran, Torpy, Burchett, 2004) Benzene is found naturally in diesel fuel, and if exposed to humans it can severely impact their overall health (Alteri, Kalidas, Gadd, 2016). The researcher included this in her experiment, so she could have a specific type of VOC to test on the bush bean plants.

The purpose of this study is to collect data about the effect of different types of scents on the health of bush beans plants (Phaseolus vulgaris). The independent variables are the different types of scents(paint, diesel fuel, flowers, none). The control group is a plant receiving no unique scent. The dependent variables are the mass, height, and leaf color of the bush bean plant. The constants are the type of water bottles, soil, water, sunlight, and time. The hypothesis is: If bush beans plants are exposed to volatile ethylene hormones from crushed flowers, then it would be affected by it the most, because they would be on constant alert all the time.

Thanks!
8th grade student
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Re: Measurement Problems

Postby SciB » Sat Oct 20, 2018 8:07 pm

Hi,

I read over your experimental write up and you did a very scientific job in organizing it. I made some minor corrections to the English for accuracy, clarity and readability:

Plants perform photosynthesis to feed themselves. Photosynthesis requires carbon dioxide, which they extract from the surrounding air using small pores called stomata on the underside of leaves. Studies done by Wolverton, McDonald, and Watkins (1984) suggested that plants can absorb harmful volatile chemicals, such as formaldehyde, using the same mechanisms. Because of this ability that plants have, people might want to use them to purify the air indoors (Claudio, 2011). The researcher wondered if the plant’s health would be affected by them absorbing these chemicals. This idea prompted her to conduct an experiment to test the effect of different types of chemical vapors that can be found in the city on the health of a bush bean plant (Phaseolus vulgaris). The data the researcher will collect could help agriculturists know which air pollutants in the environment are unsuitable for plants.

According to Consuelo and De Morales (2015), a plant’s sensory perception includes the ability to sense volatile compounds, for example, ethylene gas which causes ripening. These volatile chemicals are produced by all known plant species, (Yang and Hoffman, 1984), and some kinds are released when plants are attacked by chewing insects. This causes other plants nearby to sense the danger and put up their own defense mechanisms before they too are attacked. For example, Heil and Silva Bueno (2007) found that lima bean leaves produced more extrafloral nectar when they were exposed to damaged leaves on the same shoot. This serves to recruit insect predators, and prepares them for additional defense mechanisms. The researchers concluded that if the bush bean plants receive these volatile signals from crushed flowers they would be on constant alert all the time, therefore, growing the best.

Not only are plants able to sense ethylene gas, but they can also absorb volatile organic compounds (VOCs) (Yang, Pennisi, Son, Kays, 2009). VOCs can be emitted as vapors from paints, paints thinners, gasoline, heating oil, industrial chemicals. etc., and are often toxic to humans (Fortmann, Roache, Chang, Guo, 1998). The researcher wanted to know if bush bean plants would be harmed by VOCs from paint like humans are.

Plants can absorb toxic chemicals from the air, including VOCs such as benzene (Orwell, Wood, Tarran, Torpy, Burchett, 2004). Benzene is found naturally in diesel fuel, and if humans are exposed to high enough concentrations, it can severely affect their overall health (Alteri, Kalidas, Gadd, 2016). The researcher included diesel fuel in her experiment, so she could have a specific type of VOC to test on the bush bean plants.

The purpose of this study is to collect data about the effect of different types of volatile chemicals on the health of bush beans plants (Phaseolus vulgaris). The independent variables are the different types of chemical sources (paint, diesel fuel, flowers, none). The control group is a plant receiving no specific chemical exposure. The dependent variables are the mass, height, and leaf color of the bush bean plants. The constants are the type of water bottles, soil, water, temperature, light, and time (duration of chemical exposure). The hypothesis is: If bush beans plants are exposed to volatile ethylene hormones from crushed flowers, then it would be affected by it the most, because they would be on constant alert all the time.


I’m afraid I have to disagree with your hypothesis. For one thing, how do you know that the crushed flowers you use produce ethylene gas? I have heard that bananas produce ethylene but not flowers. Ethylene is a single chemical compound. It is not usually considered a ‘hormone’ except in a general sense, if it acts like one to a plant.

In a hypothesis you have to make a very specific statement. Saying something like “it would be affected by it the most” is not correct. You would have to say that crushed flowers will retard the growth of the plants, and I don’t see how that could happen. Also, you cannot say “they would be on constant alert” without defining what this means very specifically. I understand the idea that one plant can signal an insect attack to another by emitting a volatile compound, but what is the effect of this? It won’t stop a plant from growing, will it? What does it mean for a plant to be “on alert”? I think what you mean is that when a plant gets a specific signal about insect damage it will start producing some chemicals of its own to either repel the attackers, or as you said to attract insect predators that could eat the attackers--maybe both ways at once. This is a different response from what happens when a plant is exposed to paint fumes or diesel fumes. These can be directly toxic to plant tissues, just as they can damage a person's lungs if they breathe enough of them. I don't know if these VOCs would stop a plant from growing but at high enough concentrations and repeated exposures, they could kill leaves--and ultimately the whole plant.

I hope this helps. Please post again when you have more questions.

Sybee

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Re: Measurement Problems

Postby Ireallyneedyourhelp » Tue Oct 23, 2018 4:32 pm

Thanks for your suggestions!

I have a couple of question for you about making a good hypothesis.

Would this be a better hypothesis?

If a bush bean plant was exposed to any of the chemical vapors their health would be affected negatively.

Or do I have to only use one variable in the experiment. If so would this be a good hypothesis?

If a bush bean plant isn’t exposed to diesel fuel then their health would be affected negatively.

Do I also have to mention a specific type of dependent variable? Is so what should I use?

Should I include a “because” after the “then” in the statement?

Thanks,
8th grade student
:D

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Re: Measurement Problems

Postby SciB » Tue Oct 23, 2018 5:23 pm

Good questions! You are thinking about the hypothesis in the right way.

If I understand your ideas right you think that paint and diesel fumes will stunt the growth of the bean plants while crushed flowers may make them grow better. Is that a fair description of what you think will happen?

So, the best way to make a hypothesis out of these ideas would be to state them as three hypotheses:

H1: The growth of bean plants will be negatively affected by diesel fumes
H2: The growth of bean plants will be negatively affected by paint fumes
H3: The growth of bean plants will be positively affected by exposure to crushed flowers

Making three hypotheses instead of one allows for the possibility that any one of these sources of VOCs may have a positive, negative or neutral affect. Your independent variable is the substance that you expose the plants to and in your case you have three in addition to the control.

The dependent variable is deliberately left unspecific because you don't know what aspect of the growth might be affected by the fumes, but you will be measuring rate of increase in height, leaf number and color, and rate of increase in mass of the plant (remember to weigh the pot and soil after planting the seeds, but before watering them).

You don't need a 'because' in the hypothesis. The reason that you think diesel or paint will harm the plants is something you will discuss in the introduction part of your report and again in the discussion after you talk about how the plants were or were not affected.

You are doing three pots per treatment, right? You need to be able to get an average value for your dependent variable and to do that accurately you need at least three samples.

Always record anything you observe or wonder about because sometimes there's an event that was not anticipated. Don't ignore anything! It may be very important. Throughout history there have been a mind-boggling number of observations that have been overlooked or passed by that could have changed the world. The Greek Heron experimented with steam power back in 40 CE and actually built a steam-powered turbine of sorts (https://en.wikipedia.org/wiki/Aeolipile), but the people ignored it, treating it as a toy. Just think how different history would have been if the Romans had built steam engines. The Roman empire might not have fallen to the 'barbarians'.

Good luck and keep in touch,

Sybee

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Re: Measurement Problems

Postby Ireallyneedyourhelp » Thu Oct 25, 2018 6:17 pm

Hi Sybee!

I have some questions for you again about my hypothesis.

Could I combine all three hypothesis together?

For ex. "If bush bean plants are exposed to any of the types of volatile vapors other than the ethylene their health would be affected negatively."

It doesn't mention that the ethylene hormones can help the plant grow better, but doesn't it seem implied?

I did more research about the ethylene found in bananas and it said that when start ripening they cause other fruits nearby to ripen as well. So since I would only be growing the bush bean plant for three weeks, wouldn't the plants exposed to ethylene mature at a faster rate and grow more than the other plants? Does this explanation make sense to you?

Thanks for your help!
8th grade student
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Re: Measurement Problems

Postby SciB » Thu Oct 25, 2018 6:47 pm

Hi again,

Technically you should not combine hypotheses because each one has a different independent variable. There's nothing wrong with having multiple hypotheses with each one having a different outcome, potentially.

The only function of ethylene that I know of is to make fruits such as bananas and tomatoes ripen. You should do a search and see if you can find other functions. Just because ethylene affects fruit ripening does NOT mean that it has any affect at all on plant growth. Don't confuse one with the other. Scientists don't assume. They prove their statements using experiments and data--there's or from a published research paper.

Also, you cannot say that crushed flowers produce ethylene without proof. Crushed flowers will emit some VOCs but you will not be able to say WHAT they are. If you want ethylene, put a piece of banana in the bottle.

You can do the experiments as you planned them, just be careful what you say and what you conclude.

Sybee


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