Info
| Explore | - Spider plants (Chlorophytum comosum) are perennial herbs that are to grow to 60cm high. - Often found in the variegated variety (usually Vittatum or Variegatum), though purely green spider plants also exist. - Able to thrive in a variety of abiotic factors; tolerates temperature down to 35... |
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| Research Question | What effect does humidity have on the growth of tuberous routes (spiderettes) of spider plants (Chlorophytum comosum)? |
| Predictions | There are three possible outcomes to our experiment: the plants' roots with the increased humidity will grow more than the plants with regular humidity; there will be no significant difference between the root growth of the increased humidity plants and regular humidity plants; the plants' roots... |
| Experimental Design | Our plan is to test the effect of the relative humidity of the baby spider plants. The variable that we are testing is the relative humidity. We are going to have two levels of the independent variable: no enhanced humidity and enhanced humidity. In order to achieve these levels. we set up 12... |
| Conclusion | What claim can we make from our experiment? What are possible explanations for our results? How do the data we collected and our reasoning with scientific ideas support our claim? What future experiments could be done to expand on the results of this experiment? |
| About this Project |
This team did an excellent job with all aspects of our introduction to research project with planting science. I was especially impressed with their attention to detail with respect to data collection and the relatively large number of samples that they used in their study. The part that I... |
Updates
Hi Win(sto)ning Team,
First I want to congratulate you on a job well done! I just started reading your Final Report and it is amazing. Everyone has put in a lot of time and attention to details from the experimental setup to measurements and results. Please pat yourself on the back!
Second there are a few things I wanted to point out. It makes me smile that you have stated that your prediction was wrong and that the plants with humidity may not grow as well as plants without humidity. You would be surprised how many people at every stage of a science career don't have the courage to say that their prediction was wrong. Third I wanted to applaud you for diligently mastering every part of the your project. You came up with a great idea to test and hopefully future classes will consider testing different treatments using spider plants! Fina;ly your graphs look amazing. Figure 8 and 10 in particular show exactly what you determined in your conclusion.
It was an honor working with you this term.
PS I finished reading the report and your observation of the "bag effect" is awesome! In my mind it clearly suggests that the bag could be helping growth like it was a miniature greenhouse! Awesome observation!
best,
Johnathon
Thank you for all your praise and your attentiveness throughout the whole project. I know that we could not have accomplished what we did without your help and support.
Best regards,
Kyle
Hi Johnathon,
Now that our experiment has concluded and our research paper has been written (attached in files) we would like to thank you for all the help you have given us. Your questions, observations, and general feedback not only helped us improve and refine our experiment, but also helped us reach a deeper understanding of several topics involved in the experiment.
Thank you so much!
Josh, Kyle, Phylicia, Arsh, and Winston
Hi Guys,
Awesome! I am very glad I was able to help!
Johnathon
Hello Johnathon,
I would like to personally thank you for the effort you put into helping us with our planting science experiment. Your guidance helped us improve the experiment and investigate topics that we would have never otherwise considered. You were extremely active and gave helpful feedback to all of our posts. It was greatly appreciated.
Thank You,
Arsh
Hi Arsh,
Thanks for the complement. It was an honor to work with you!
Johnathon
Hi Johnathon,
Our team hypothesized that increasing the relative humidity level would have a positive effect on the growth of the tuberous roots of spiderettes. However, our hypothesis was disproven because the presence of a sponge inside the plastic bag had no significant influence on on root growth. On average, the total root length for the spiderettes without increased humidity was 3.783 cm more than the total root length for the spiderettes with increased humidity. From this, our team concluded that increased humidity may have a negative effect on root growth. Additionally, we may have increased the humidity too much, which was harmful to the spiderettes.
We will also be uploading the paper for our experiment soon.
Thank you,
Phylicia
Hey Johnathon,
During the final collection phase of our data, we had to measure the roots of the spiderettes. We did this by cutting the spiderette off using one of our teacher's pruning snip. Afterwards, we laid it off against a standardized graph paper and measured the roots with a ruler.
While creating the graphs and charts for this information, we found that the plants with the sponge inside its bag generally grew less than their counterparts without the sponge. Despite this, the bag without the sponge contained plants that grew significantly more tuberous roots than that lacking a plastic bag.
This has led us to believe that there is a limit of humidity in which the spiderette tuberous roots grow at optimum.
Hi Guys,
Phylicia mentioned you did not see a difference in root growth between the two treatments. What are some ideas as to why this may be the case? Also what was the measured difference in humidity between the different groups of bags?
Thank you for uploading the photos. I am now interested if your results would change if you cut the plantlets from the mother plant. It is hard to tell but this may induce rooting. Do you know if there were any roots on the plantlets before starting the experiment?
best,
Johnathon
Hello Johnathon,
We have finished collecting all our data and are in the process of working on the research paper right now. During the experiment, the root length of all trials, control and experimental, seemed to drastically increase. However, even though there was a greater amount (about 20%) of relative humidity in ziploc bags with wet sponges than there was in ziploc bags without wet sponges, the two treatments did not have much of a difference in root growth. We think it might be because the effect of humidity on root growth for baby spider plants might be a curve. After the relative humidity hits a certain number, the root growth probably peaks. After that, the root growth starts to decrease. This peak is likely around the 65% mark which was around the humidity of the bags of the control group.
Most plantlets did not have any noticeable roots before the experiment started. Some might have had a few extremely small roots.
Also, we have cut the baby spider plants from the mother plants and placed them in soil for them to grow. There are several aspects of the experiment we could have done differently which could prompt further study.
Thank You,
Arsh
Over the past two weeks we have collected data for the root growth (number or roots per plant in addition to the average root length for each plant). Today, our group began the completion of our final write up for our project. My job was to list all the materials, equipment, and facilities that we used during the the course of the experiment. I am also writing about our suggestions for further study if we were to continue upon our hypothesis.
Hey Johnathon,
The software we are using to collect data about the humidity of the ziploc bags is called Logger Pro. Here is a link to their website if you want to know more about it: https://www.vernier.com/products/software/lp/ .
It is a software that is connected to the humidity sensor, and it graphs the humidity levels, changing every second. We are using this setup to collect data for the humidity levels right now. I uploaded the photo of the setup so that you can visualize it.
Thank You,
Arsh
Hi Johnathon,
Overall, we aren't seeing a significant difference in the number of roots so far. There was no change for some pairs, while there was a drastic change for other pairs. The average number of roots when we increased humidity was 5.2, and the average number of roots when we did not increase humidity was 5.6.
Phylicia
Hello Johnathon,
As we were collecting our data relating to the humidity of each of the bags, we noticed there were a few droplets of water on the inside of the ziploc bags that did not have sponges in them. Mr. Roche brought this up to us when he noticed it and informed us that it was probably because the plants were transpiring. We believe this is contributing to the rise of humidity levels in all the ziploc bags.
From,
Arsh
Hi Johnathon,
We are collecting the following pieces of data:
- The root lengths of each root of each spider plant
- The final humidity of each plastic bag (as well as the outside humidity)
- The number of roots each spider plant has
Thanks, Josh
Hello Johnathon,
Recently, we have began collecting data in a manner in which to ensure standardization in procedure as to minimalize variation in data stemming from the collection phase. The relative humidity sensor is the same model as detailed before, and is able to collect information both precisely and accurately. It is connected to Vernier's "Logger Pro" software, which record the data.
The process is as follows:
1. The plastic bag is opened
2. Immediately afterwards, the relative humidity sensor baton is inserted parallel to the opposite edge of the plastic bag as to reduce gas exchange from occurring due to the opening of the plastic bag.
3. The sensor is engaged and held stationary for about 30 seconds
4. The sensor is able to record the data onto the software, and is extracted from the bag.
5. The bag is resealed.
6. Repeat steps 1-6 for all twenty-four spider plants.
During our data collection, we ran into a rather significant. The aforementioned problem concerns the integrity of our data collection, as operational error may have corrupted certain data points; the humidity sensor seemed to have malfunctioned towards the end of our activities, since it was giving faulty humidity sensor readings; therefore, we had to suspend procedures until we could resolve this issue. Over a duration of half an hour, we were able to redress this problem and return to collecting humidity readings.
From,
Winston
Hi Johnathon,
Right now we are collecting data from our spider plants. One interesting observation we noted is the difference in growth between the plants in the bags and the plants outside of it. The plants inside the bags, regardless of whether or not they have the sponge, have much more, and much larger roots than the plants outside of the bags. We think that this may be due to the greenhouse effect you mentioned and because of the way moisture is trapped inside the plastic bags.
Thanks, Josh
Hi Johnathon,
Today, we collected data on the number of roots. I will reupload the team planning document so you can see our data.
Thank you,
Phylicia
Hello Johnathon,
Our group was wondering about the viability of making the sandwich bags airtight. We are worried if this will interfere with the oxygen and carbon dioxide supply of the plant. Furthermore, this may hinder any opportunities to re-add water to the sponges.
Of course, we will heed your advice. We can try to do two trial runs with the air-tight seal.
Hi Winston,
You are right and usually it is not good to completely seal the bag. On the other hand, it is very hard to keep a constant relative humidity when air can easily exchange between the outside and inside of the bag. Your test runs will tell you if you can keep a constant humidity without sealing the bag.
Hello Johnathon,
Currently, our team has decided on adding one milliliter of water to each bag with sponge present, and has created a responsibility cycle for it.
Regarding your concerns for the exchange of gas, we do agree with you that there will be an unequal amounts of gas exchange. Despite this, completely sealing the bags will most likely kill the plants, rather than resolve this problem. Moreover, sealing the bag will make attempts at adding water to maintain humidity in the sponges impossible. The plants are planted in extremely similar locations: height, temperature, and location in regards to sunlight.
Furthermore, we have tried our best to make the cavity within the seal as similar as possible. The bags are sealed extremely tightly around the root itself, and the root runs parallel along the edge of the bags.
Thanks,
Winston
Hi Winston,
This sounds good. If possible can you send a picture? I am very curious what the setup looks like.
best, Johnathon
Hi Johnathon,
We changed the amount of water added to each sponge per day to 1.5 mL, because we had trouble getting exactly 1 mL of water in the pipet. We believe that this will describe our experiment more accurately.
Thank you,
Phylicia
Hi Phylicia, this sounds good.
Hi Johnathon,
I attached several different pictures to help you get a better understanding of our experiment.
Thanks, Josh
Hi Josh,
Awesome pictures, now I have a better idea what you are doing.
I remember talking about how the plantlet smay desiccate if they are cut off from the mother plant. I am wondering if I was wrong and if you should cut the plantlets off at the stem. I don't know enough about spider plants but there may be a mechanism where a plantlet only forms roots if they sense soil or if they are cut off from the mother plant.
Do you see any roots on any of the plantlets already attached to the mother plant?
Hi Johnathon,
The plantlets already had small, but noticeable roots. Since we planted last week, the plant roots have grown a little bit.
Thanks, Josh
Hi Josh, thanks for this piece of information.
Hey Johnathan,
We are currently on our sixth day of experimentation. So far, our results are inconclusive. There is no significant difference between the two different sets of plantlets. However, it is still early on in the experiment, and we hope to see a noticeable difference in averages. Until then, we will continue to study, and keep you informed every time we make a discovery.
Thanks,
Kyle
Hi Kyle,
This sounds good. You may want to extend the time the plants are exposed to humidity but I know how you are limited by the number of days you can do the experiment. Maybe when the experiment is over in the class you can take them home and test them for a longer period of time.
Hey Johnathon,
We are starting to see the growth of roots on the baby spider plants after three days. In the start of the experiment, there were no noticeable roots on any of the baby spider plants. Now, most of the spider plants have a good amount of root growth. We have 12 pairs of bagged baby spider plants, one with a wet sponge and one with no sponge. We made sure that each pair had a similar size and position in the beginning of the experiment. While in most of the pairs the growth of the roots on the baby spider plant with enhanced humidity is higher than their non-sponge counterpart, there are some pairs where the baby spider plant with no sponge is growing more roots than the one with the sponge. Do you have any thoughts on this?
Thanks,
Arsh
Hi Arsh,
I am not sure but it could be a number of things. Maybe humidity does not change root growth or maybe it is biological variability (this is a fancy term for random differences due to the genetics or the genetics interacting with the environment).
best, Johnathon
In the .pdf I submitted, we have outlined our experiment in an experimental design diagram, a technique that our teacher taught us to give a strong description of our project by defining the most important components.
Hi Kyle,
This is very good. It will help you when you present your results.
The 12 cut sponges that Josh sent a photo of are not all the same exact size; however, they are all around either 3x4 cm or 3.5x4 cm. Nonetheless, we believe that the size of the sponge would not make a difference since we are putting the same amount of water on each sponge. Side note: the grid in the background does not line up with any whole number measurement.
Hi Arsh,
Even though the sponges are different sizes it should be ok, especially when the amount of water is the same for each.
Hi Johnathon,
Got it, thank you. I created some data tables on the team planning document for our measurements.
-Phylicia
Dependent Variable: Number of roots
We will measure how different levels of humidity affect the growth of roots by counting the number of roots for each sample.
Hi Phylicia,
This is a good dependent variable. Can you also think of any other measurements you can take? What about root color and total root length for the longest root. Maybe also the total length of the shortest root. You may be surprised to find that the humidity changes more than just root number!
best,
Johnathon
Hi Johnathon,
Thanks for your help! We will be measuring the total length of the shortest and longest root as well as the average length of the roots and the number of days until the roots appear.
-Phylicia
Hi Phylicia,
These are very good measurements. Since you are calculating the mean length it may help to measure all the roots for each plantlet. This way you already have the largest and smallest lengths along with the numbers required to measure average root length.
It should not be difficult because hopefully the plantlets will not produce very many roots.
best,
Johnathon
Our team is considering on subjecting tuberous roots to varying levels of humidity as the independent variable of our experiment. The tuberous roots are covered in a thin plastic wrap to separate them from other samples. The humidity may be regulated by adding sponges of different wetness to each compartment. We also have tools that can measure the humidity
Hi Winston,
What type of device do you have for measuring humidity? Also I suggest performing a "test run" without any sponges and just the wet soil that holds the spider plant. I have performed humidity tests myself using a moss called Physcomitrella patens. When I did my tests I sealed the moss plants in an air tight container with water. The humidity immediately went up to 90% and I learned that I needed to remove the humidity! You may learn that you need do the opposite of adding water. One way to do this is to add small packets of silica gel to the covered plants. These little packets of silica gel are the same packets that you may find in a new pair of shoes. They remove water from the atmosphere but they have a "saturation point." This means that after acting to remove water for a while, the packet will no longer work.
best,
Johnathon
Our instructor has told us that he has a "Relative Humidity Sensor," as listed here: https://www.vernier.com/products/sensors/rh-bta/.
We can do test runs. Also, the idea of using the silica gel as a regulator is very helpful. We will be trying to acquire such materials.
Hi Winston,
These are good RH sensors. You probably already know this but it may be tricky to seal the bags with the cord hanging out. If you have any caulking or hot glue you may be able to create an airtight seal. You will be able to test this by pressing on the closed bag to see if air escapes.
I recently found some cheap RH/temp sensors that I plan to buy for my own projects at home and at work. Files They look great for putting in my greenhouse. The advantage to these are that they are very small and they display the measurement but they don't record it. Unfortunately they are probably not as accurate at the type you have which is rated at 0-95% +/- 5%. The +/- 5% part part of the "resolution error of the instrument." Almost every instrument has a resolution error. It means that the relative humidity reader may accidentally overestimate or underestimate the RH, but never more than 5%. You can think of the resolution as how many decimal places your humidity reader can record. For instance a very fancy (expensive) humidity reader may be able to report a value such as 85.019% humidity. This instrument would have a high "resolution."
best,
Johnathon
Hey johnathan,
I'd like to respond to a few of your questions to Arsh. Referring to the roots, our instructor is quite certain that spider plants have fibrous roots, but we do have an adult plant at our disposal that we will dig up to check. Also, we already have the humidity sensors in our school's research lab, and as of right now we plan on checking the sensors once a day during the school week for the entirety of the project.
Thanks for your input and positive feedback
sincerely,
Kyle
Hi Kyle,
You probably don't need to dig up the adult plant especially with your current experimental design. I was afraid that you may be working with a large complex mass of roots and that it would be hard to measure the root lengths. Often times roots can get out of control!
With your plantlets inside the ziploc bags it will be easy to align a ruler to each root in order to make the measurement.
best,
Johnathon
Hi Johnathon,
It seems as if we were not clear enough when describing the plans for our experiment. This is a clarified overview of our experiment:
- We have access to adult spider plants that have many baby spider plants growing off of it.
- We are going to use 24 of these baby spider plants that are going to still be hanging from their adult plant.
- 12 of them will go in Ziploc bags with no sponges whatsoever. This will be the control group.
- 12 of them will go in Ziploc bags with small wet sponges inside it. We will use humidity sensors to keep the humidity levels in these twelve Ziploc bags around the same level. This is going to be our experimental group.
- Essentially, we want two levels of humidity being tested: no humidity and enhanced humidity.
- We are hoping that by putting all of the baby spider plants in Ziploc bags the temperature will stay around the same.
- We plan to measure the data about the roots periodically over two weeks without taking the baby spider plants out of their bags.
I hope this clarified some of your concerns about the experiment. Josh has also answered some of your other questions. Please reply to this post if you have any other questions/concerns you want us to address.
Thank You
Hi Arsh,
This summary is perfect, thank you.
Since the two ziploc bags will be placed in the same environment they should be the same temperature (hopefully). I suggest that if you have two manual or digital thermometers you put them in the ziplocs as well. It is ok if you don't have these.
It may be important to keep in mind that the "plantlets" are currently receiving mineral nutrients from the mother plant in addition to water. Therefore the plantlets without any water may not grow or they may become desiccated.
best,
Johnathon
Hi Arsh,
I am sure you are already thinking of this but I suggest a numbering scheme for each plant: noH1-noH12 and H1-H12. If you have tape you can probably tape this number to the leaf without it interfering with the experiment.
Then you can make an excel spreadsheet with the days at the top (columns) and the plant identification on the rows. This way you can easily write down the date, the temperature, and measure each root for each plant.
The materials that we will be using for the experiment are baby spider plants, clear Ziploc bags, humidity sensors, and wet sponges. This will allow us to efficiently set up the control and experimental groups and easily measure the data through the transparent bag.
Hi Arsh,
I like this idea because the materials are readily available. One problem is that making a custom greenhouse using Ziploc bags is likely to change two variables: temperature and humidity (in addition to other minor things like soil bacteria growth and maybe even moss growth at the surface of the soil). Therefore you would be testing the effect of both temperature and humidity.
There are a few things you can do. You can try to make the temperature the same between your greenhouse plants and your non-greenhouse plants. This is very hard to do without expensive equipment. At the place that I work, we have very expensive greenhouses that can mimic the outside temperature and lighting while maintaining a high humidity. Another option is to measure both temperature and humidity and in your results you would say that an observed difference in root number is due to "temperature, humidity or both." Scientists do this a lot when they are unable to separate two variables that are closely related to one another.
I haven't had time to look at your files yet but I have a lot of questions about your experimental design. Do you plan to cover the plants completely and close the bag? Will you add the humidity treatment at the start when the plants are still small? How many of them do you have? If you have a lot of them you can perform what is called "replication." Replication is the ability to see an effect (say producing more roots) more than once in order to give further support to your conclusion. Finally what type of soil will you be using?
Also do you have any adult spider plants? If so is it possible to remove them from the pot in order to get a better idea of what the roots look like? Plants typically have one of two types of roots. These are called fibrous root and taproot.Files
best,
Johnathon
Also do you have the humidity sensors already? How often during the day do you plan on taking measurements?
Hi Johnathon,
We are planning on completely covering and sealing the bags as much as we can and we are using 'baby' spider plants over the duration of the experiment. We are planning on using 24 'baby' spider plants and performing replication. We are planning on not using any soil for our experiment.
Hi Arsh,
Thanks for the clarification. Removing the soil should be a quick way to minimize bacterial or fungal growth that may inhibit the experiment. It sounds like a good design.
Hi Kyle, Arsh, Josh, Winston and Phylicia,
My name is Johnathon and I am sorry to see that your project did not get a mentor in time but I am happy to say that I am here to help. I am not sure if I will be the permanent replacement mentor for the duration of your experiment but I am here to help for the time being. I will mostly focus on your most recent posts and ask a few questions. It is great to see that your team is off to a good start.
best,
Johnathon
Our experiment has been well thought out and we have consulted with Mr Roche. However, we would love to hear any input you may have. Even though we are leaning towards humidity testing, any modifications or fresh ideas that you would like to help widen our horizon would be greatly appreciated. Thank you!
Hi Kyle,
It is good to hear that you are on track to conduct your experiment. Feel free to keep me updated on any new ideas that you may have for your project.
Good luck.
best,
johnathon
Hi,
To help us manage our time better we created a Gantt chart, which helps us visualize how much time we have for each task. The Gantt chart details the start date of each task and how long we have to complete it. The chart will be attached to this project page.
Hi Josh,
Great work. It always helps to be organized and to have a plan!
best,
Johnathon