8 Water Tricks That'll Melt Your Mind

Annotated Standards

Annotated Standards

of Science

Ryan McGill

Austin Gydesen

Bethany Felker

Initial Draft

Austin Gydesen, Ryan McGill, Bethany Felker

Annotated Standards Group Project

Technology Standards

1) Creativity and innovation - Students demonstrate creative thinking, construct knowledge, and develop innovative products and processes using technology. To do this they will apply existing knowledge to generate new ideas, create original works, use models and simulations to explore complex systems and issues, and identify trends and forecast possibilities. Our initial reaction of this standard is that its a very good standard to have because creativity and innovation are very key attributes involved in not only technology, but learning as a whole. As far as how this standard affects us in our subject area, it means that we will need to encourage the kids to use their creativity while working with science. Whether it be having students create their own models of the solar system, or having them forecast possibilities and trends by using the scientific method, there are many ways to support growth and understanding in this area. Technology may further support these experiences because students could use online simulations and other online resources to help grow their growth and understanding.

2) Model digital age work and learning - Teachers exhibit knowledge, skills, and work processes representative of an innovative professional in a global and digital society. They will do this by demonstrating fluency in technology systems and by collaborating using digital tools and resources to support student success and innovation. We think this is also a good standard to have for teachers because it is important for teachers to lead by example and teach in that way as well. In other words, if we want our students to learn about technology and digital age work and learning, then we better do the best we can to model someone who uses technology and digital age work and learning on an everyday basis. This means that, as teachers, we need to be very tech savy and know how to use and incorporate technology and digital work and learning experiences into science. An experience we could do to support this would be that we could have online lectures and online discussion boards that way the students will have no choice but to learn how to collaborate/learn digitally. One technology that might support this experience would be PowerPoint.

3) Technology operations and concepts - Students demonstrate a sound understanding of technology concepts, systems, and operations. For this, they will understand and use technology systems, select and use applications effectively and productively, troubleshoot systems and applications, and transfer current knowledge to learning of new technologies. Our first reaction to this standard was kind of like “Duh!” of course this is a good standard to have. It’s a good standard because in today’s world everything is shifting towards technology, so it is a good idea to teach our students at least some technology concepts, systems, and operations that way they aren’t totally unprepared for the future. We could design a project where students record data and put it into a table and use that table to make a graph. Technology can further support this because we could have them do it on Excel.

4) Facilitate and inspire student learning and creativity - Teachers use their knowledge of subject matter, teaching and learning, and technology to facilitate experiences that advance student learning, creativity, and innovation in both face-to-face and virtual environments. They will promote, support, and model creative and innovative thinking and inventiveness, engage students in exploring and solving real world problems using digital tools and resources, promote student reflection, and model collaborative knowledge construction.  We think this is an important standard because this standard encompases the whole point of being a teacher.  Teachers should inspire their students to want to learn more, or to have their students think outside the box.  Some experiences we could add to this would be group projects that we have done in the past.  A way to incorporate technology into this standard would be to have students do research on the computer. Students can pick a topic, then either go to the library or look online for more information regarding their topic.  

5) Communication and Collaboration - Students use digital media and environments to communicate and work collaboratively, including at a distance, to support individual learning and contribute to the learning of others. They will Interact, collaborate, and publish with peers, experts, or others employing a variety of digital environments and media, communicate information and ideas effectively to multiple audiences using a variety of media and formats, develop cultural understanding and global awareness by engaging with learners of other cultures, contribute to project teams to produce original works or solve problems. We think this is also a good standard to have because it is important for students to learn how to work together and communicate using digital environments/media because it is a skill they will need for the rest of their lives, especially when they get to college and work in groups like this one and need to know how to use google docs. As far as what this standard means for teaching our subject which is science, it means that we can have students do a lot of group projects. One experience we could design would be that we could have students do a group project and not let them have any time in class to work on it together, that way it forces them to use a technology such as google docs in order to collaborate and get the project done.

Subject Area Standards

SC2.2.1a:Observe physical properties- Students will observe different properties of object such as freezing, melting, sinking, floating, color, size, texture, shape and weight.  This standard, we feel, is important because the whole point of science is to observe. Whenever you go out into the world, or even just sitting in a classroom, you are constantly observing your surroundings.  So to have this as a standard, we feel it is very important to discuss what we are observing.  What the physical properties of the objects are.  We can incorporate our own experiences with this by talking about our observations with looking through a microscope and observing both meiosis and mitosis.  We can also look at how thing are made and the properties of different tools used to make these things. For example, by observing the functions of both a hammer and a screwdriver, you would know when to use one or the other.    

SC12.1.3a: Explain how science advances with the introduction of new technology-  Students will use technology to describe mechanical wave properties and how the wave travels through a medium.  Types of waves technology shows include speed, wavelength, frequency, and amplitude.  Students will also use technology to distinguish between temperatures, look at nuclear reactions, and light waves.   This is a standard because it demonstrates the importance of different technological advances.  It will also help demonstrate in a classroom what life was like before a projector, or a microscope, or how without Copernicus, we would still think the earth was the center of the universe.  These different advances help demonstrate how science is used in the real world and not just in a lab setting.  

SC8.1.2b: Describe how scientific discoveries influence and change society- This standard discusses the use of having scientific knowledge and applying that use during scientific investigations. We feel like this should be taught in classrooms because it makes a point to have teachers show the uses of science in everyday life.  For example, in biology lab, teachers will talk about vaccinations and how that has saved the life of many.  Technology is important for this because students can look up articles on the computer that talk about these different scientific advances.  For us, this standard means having students do their own research and learning about how science is incorporated into everyday life.

SC2.4.1a: Identify objects in the sky (the sun, moon, stars) and when they are observable- We feel like this should be a standard, because it should be something every student should know.  Every student should be able to identify the sun in the sky or the moon.  They should also learn that the moon does not create its own light but rather the light we see is just the light from the sun bouncing off the moon. This standard, we feel, merits being a standard because it should be in every teaching curriculum at some point in time.  And students studying science should be taught to identify these objects.  Some experiences we could use to create growth and understanding about this subject area might include when we went outside and observed the stars through a telescope or discussed what we learned in our astronomy class.  Technology that is used in this standard could include  looking at satellite imaging or even looking through a telescope.  

SC8.1.3g: Explain how science and technology are reciprocal- We feel like this is a good standard to have because we think that science and technology go hand in hand.  You cant have one without the other.  To make advancements in science you need to use technology to understand the experiment. Even if you were doing a simple titration, you would need to use technology to understand the safe amount of chemicals to add.  For our life experiences, we could discuss our experiences in how science and technology go hand in hand.  We could have our students do research on new vaccines, or new methods to help cure the common cold. Technology is needed to help with this though because it is one of the tools scientists use in order to make advancements.  

Conclusion-

Science is experiencing constant and ongoing changes all the time.  With the change in science it is allowing for the development of new technologies all the time.  As science continues to change it is our responsibility as teachers to stay up to date and current on all the technologies that we can, especially the ones that we would be able to implement into the classroom.  By doing so it will allow us as teachers to deliver the best learning experience to our students as possible.  This will only further their abilities and knowledge with current and new technologies.

Peer Review for Annotated Standards

              Completeness: This document is complete with the information that was needed.  There are no missing pieces or titles.

        Organization: Here you could have possibly put in the “a.), b.), c.), etc.” under every standard that you were writing your comments on.  This way you could keep it fluent but still give the polished and organized feel!

        Analysis: The analysis is very straight-forward with multiple pieces of information/ideas on each standard. We think that there could possibly be more in-depth with some of your answers… going the extra little bit to explain your reasoning could add to it.

        Clarity: This project is very straightforward and easy to understand.  It may have been much simpler if you gave the bullet points/letters to show each separate thought.

        Adaptations: I think that this document was unique in the sense that it was a cohesive response to the standards versus separating each question and response out.  While we think that it would be much more beneficial to give the bullet points, there is still some value in keeping the document as one fluent thought on a standard versus separate responses.

Ivy and Alexis

Final Draft

Austin Gydesen, Ryan McGill, Bethany Felker

Annotated Standards Group Project

Technology Standards

1) Creativity and innovation - Students demonstrate creative thinking, construct knowledge, and develop innovative products and processes using technology. To do this they will apply existing knowledge to generate new ideas, create original works, use models and simulations to explore complex systems and issues, and identify trends and forecast possibilities.

A) Our initial reaction of this standard is that its a very important standard to have because creativity and innovation are very key attributes involved in not only technology, but learning as a whole.

B) This standard merits being a standard because of the importance of creativity and innovation involved in learning and technology.

C) As far as how this standard affects us in our subject area, it means that we will need to encourage the kids to use their creativity while working with science.

D) Whether it be having students create their own models of the solar system, or having them forecast possibilities and trends by using the scientific method, there are many ways to support growth and understanding in this area.

E) Technology may further support these experiences because students could use online simulations and other online resources to help grow their growth and understanding.

2) Model digital age work and learning - Teachers exhibit knowledge, skills, and work processes representative of an innovative professional in a global and digital society. They will do this by demonstrating fluency in technology systems and by collaborating using digital tools and resources to support student success and innovation.

A) We think this is also a good standard to have for teachers because it is important for teachers to lead by example and teach in that way as well. In other words, if we want our students to learn about technology and digital age work and learning, then we better do the best we can to model someone who uses technology and digital age work and learning on an everyday basis.

B) This standard merits being a standard because it is important that teachers model themselves as tech savvy professionals, since the goal is for the students to sort of pick up on some of the knowledge that their teachers have.

C) This means that, as teachers, we need to be very tech savvy and know how to use and incorporate technology and digital work and learning experiences into science.

D) An experience we could do to support this would be that we could have online lectures and online discussion boards that way the students will have no choice but to learn how to collaborate/learn digitally.

E) One technology that might support this experience would be PowerPoint, or even Google Docs, because both of them can be used to collaborate digitally.

3) Technology operations and concepts - Students demonstrate a sound understanding of technology concepts, systems, and operations. For this, they will understand and use technology systems, select and use applications effectively and productively, troubleshoot systems and applications, and transfer current knowledge to learning of new technologies.

A) Our first reaction to this standard was kind of like “Duh!” of course this is a good standard to have!

B) This standard merits being a standard because in today’s world everything is shifting towards technology, so it is a good idea to teach our students at least some technology concepts, systems, and operations that way they aren’t totally unprepared for the future.

C) For teachers, this standard means that we need to incorporate technology into our classes, and make sure the students know how to use the different technologies.

D) We could design a project where students record data and put it into a table and use that table to make a graph in order to illustrate the data in the table.

E) Technology can further support this because we could have them do it on Excel or Google Docs spreadsheet, which would further broaden their knowledge of technologies.

4) Facilitate and inspire student learning and creativity - Teachers use their knowledge of subject matter, teaching and learning, and technology to facilitate experiences that advance student learning, creativity, and innovation in both face-to-face and virtual environments. They will promote, support, and model creative and innovative thinking and inventiveness, engage students in exploring and solving real world problems using digital tools and resources, promote student reflection, and model collaborative knowledge construction.  

A) We think this is an important standard because this standard encompases the whole point of being a teacher.  

B) This merits being a standard because as teachers, the number one goal is to facilitate knowledge, learning, and creativity. In our opinion the number two goal would be to inspire the students in a way that makes them want to learn and create, so obviously any standard that combines the two main goals of teachers, should be a standard.

C) Teachers should inspire their students to want to learn more, or to have their students think outside the box.  

D) Some experiences we could add to this would be group projects that we have done in the past.  

E) A way to incorporate technology into this standard would be to have students do research on the computer. Students can pick a topic, then either go to the library or look online for more information regarding their topic.  

5) Communication and Collaboration - Students use digital media and environments to communicate and work collaboratively, including at a distance, to support individual learning and contribute to the learning of others. They will Interact, collaborate, and publish with peers, experts, or others employing a variety of digital environments and media, communicate information and ideas effectively to multiple audiences using a variety of media and formats, develop cultural understanding and global awareness by engaging with learners of other cultures, contribute to project teams to produce original works or solve problems.

A) At first glance, we believe this is a very important standard, maybe even the most important.

B) We think this merits being a standard because it is important for students to learn how to work together and communicate using digital environments/media because it is a skill they will need for the rest of their lives, especially when they get to college and work in groups like this one and need to know how to use google docs.

C) As far as what this standard means for teaching our subject which is science, it means that we can have students do a lot of group projects, both digitally and non-digitally.

D) One experience we could design would be that we could have students do a group project and not let them have any time in class to work on it together, that way it forces them to use a technology such as google docs in order to collaborate and get the project done.

E) There is a vast list of technologies that could be incorporated in order to support these standards including Google Docs and Prezi.

Subject Area Standards

SC2.2.1a:Observe physical properties- Students will observe different properties of object such as freezing, melting, sinking, floating, color, size, texture, shape and weight.  

A)This standard, we feel, is important because the whole point of science is to observe. Whenever you go out into the world, or even just sitting in a classroom, you are constantly observing your surroundings.  By learning to observe the properties of certain objects, you gain a better understanding of the world around you.  If you know why ice melts, you can try to save the polar bears.  To be able to observe physical properties is a very important life skill to have.

B)So to have this as a standard, we feel it is very important to discuss what we are observing.  What the physical properties of the objects are.  Even though this standard is kind of an obvious thing to teach especially in a science field, we feel that it is important to have it written out for every teacher to know and understand.  That way there is no question as to what should be taught in a science classroom.

C) We feel that with this standard, we can incorporate many hands on experiments in our classroom.  By being able to observe changes of state, or how to make a golf tee, students can learn and understand the world around them.

D)We can incorporate our own experiences with this by talking about our observations with looking through a microscope and observing both meiosis and mitosis.  We can also look at how thing are made and the properties of different tools used to make these things. For example, by observing the functions of both a hammer and a screwdriver, you would know when to use one or the other.    

E)Technology will be able to support the ways we teach science because science and technology go hand in hand.  We need a microscope to look at bacteria or cells of a plant.  We need a telescope to be able to understand our universe.  So we will be able to use technology no matter what subject we teach.  

SC12.1.3a: Explain how science advances with the introduction of new technology-  Students will use technology to describe mechanical wave properties and how the wave travels through a medium.  Types of waves technology shows include speed, wavelength, frequency, and amplitude.  Students will also use technology to distinguish between temperatures, look at nuclear reactions, and light waves.   

A) We feel like this should be a standard because it helps students understand how much technology influences the science field.  It helps to show students what they need to understand about the world around them.  When a new technology is discovered to help solve a science question, science is improved.  We wouldn't be able to calculate velocity as accurately as we do now without some physics scientist inventing a machine to help us.  

B)This is a standard because it demonstrates the importance of different technological advances.  It will also help demonstrate in a classroom what life was like before a projector, or a microscope, or how without Copernicus, we would still think the earth was the center of the universe.  These different advances help demonstrate how science is used in the real world and not just in a lab setting.  

C) For us in the teaching world, we will be able to bring in news articles about different advances, we will be able to incorporate group discussion about why the students think this will help advance technology and what they think this will mean for the future of science.  

D)We can discuss different times we had used technology to help us write a science report, or when we went to look through a telescope to see the night sky.  We could make assignments where the students bring in readings and share their new technologies with the class.

E) Students will need access to computers to research the different ways that technology is helping to advance science, so when thinking about how technology could be incorporated this is one way to go about it.   

SC8.1.2b: Describe how scientific discoveries influence and change society- This standard discusses the use of having scientific knowledge and applying that use during scientific investigations.

A)We feel like this should be taught in classrooms because it makes a point to have teachers show the uses of science in everyday life.  For example, in biology lab, teachers will talk about vaccinations and how that has saved the life of many.

B)This merits being a standard because teachers need to bring real life experiences into the classroom.  A lot of students learn better when they can see the real world application.  So by this being a standard, students and teachers are able to look at the different discoveries and see how society is influenced by these.

C)This standard means that as a teacher we will need to be able to discuss with our students the different discoveries that influence society.  We will need to be able to explain clearly to the students how these discoveries are very important to our society and how they are important to the students themselves.

D)When we were all in a science class, we had to write research papers.  We had to go to a computer, look up a certain topic, and write a 10 page report on that.  In doing so, we became well versed in our topics we were learning and we could give a presentation on that topic.  If we spit the students into groups, then had each group research a certain scientific discovery, then that group of students would learn about how that discovery influenced society and how that discovery could influence them.

E)Technology is important for this because students can look up articles on the computer that talk about these different scientific advances.  For us, this standard means having students do their own research and learning about how science is incorporated into everyday life.

SC2.4.1a: Identify objects in the sky (the sun, moon, stars) and when they are observable- A)We feel like this should be a standard, because it should be something every student should know.  Every student should be able to identify the sun in the sky or the moon.  They should also learn that the moon does not create its own light but rather the light we see is just the light from the sun bouncing off the moon.

B)This standard, we feel, merits being a standard because it should be in every teaching curriculum at some point in time.  And students studying science should be taught to identify these objects.  

C)We think that having this as a standard, it means that we need to make sure our students are able to identify different objects in the sky.  They should be able to look out their bedroom window and look at the big white ball in the sky and realize that that object is our moon.  It is an object that circles the Earth and will constantly be doing so.  They should be able to tell the difference between an airplane and a star.  

D)Some experiences we could use to create growth and understanding about this subject area might include when we went outside and observed the stars through a telescope or discussed what we learned in our astronomy class.  Students should be able to have the understanding of different objects in our sky.  

E)Technology that is used in this standard could include looking at satellite imaging or even looking through a telescope.  Also students could use the website, Google Earth to look at different rotations in our sky.  

SC8.1.3g: Explain how science and technology are reciprocal-

A)We feel like this is a good standard to have because we think that science and technology go hand in hand.  You cant have one without the other.  To make advancements in science you need to use technology to understand the experiment. Even if you were doing a simple titration, you would need to use technology to understand the safe amount of chemicals to add.  

B) This merits being a standard for obvious reasons.  It is understood that you need one to help the other.  In order to gain a great experience and understanding in the science field, you need technology to get you there.  This standard is very important to help students see the real world applications of science, and to understand the use of different technologies.  

C)For us in teaching, we should be able to incorporate science in whatever we are working on whether it be giving a lecture, or having the students do a lab.  We should be able to explain why science and technology are so important and how they go hand in hand.  

D)For our life experiences, we could discuss our experiences in how science and technology go hand in hand.  We could have our students do research on new vaccines, or new methods to help cure the common cold.

E)Technology is needed to help with this though because it is one of the tools scientists use in order to make advancements.  Technology is also able to help us understand the world around us.  It is able to give students and teachers hands on experience in understanding different things in our world.  

Conclusion:

Science is experiencing constant and ongoing changes all the time.  With the change in science it is allowing for the development of new technologies all the time.  As science continues to change it is our responsibility as teachers to stay up to date and current on all the technologies that we can, especially the ones that we would be able to implement into the classroom.  By doing so it will allow us as teachers to deliver the best learning experience to our students as possible.  This will only further their abilities and increase their knowledge and competence with current and new technologies.

Reflection:

When rewriting our annotated standards paper, we separated each of our topics into different bullet points.  By doing this it made our paper seem more organized and then we were able to discuss more fully on each of the topics we needed to write about.  By receiving feedback, we were able to see how our paper looked to other people. To us, we liked writing our paper without the bullet points, but then after receiving our feedback we learned that to make it more organized, we should add the bullet points.

By giving feedback to other groups, we were able to look at how other groups wrote their papers.  We could then take some ideas of how they organized their papers and we could incorporated those ideas into our final draft.

Finally, being able to write this and to research our subject areas standards, we were able to learn about the standards schools require us to uphold as teachers.  We were also able to learn about the different topics we would be teaching.    

Ecology and Evolution Paper 2014

The effect of increased salt concentrations, specifically sodium chloride and calcium chloride, on the per capita growth rate of Spirodela polyrrhiza

Remy Sass, Bethany Felker, Jennifer Blake

Ecology & Evolution

Thursdays 1:30-4:20, Section 152

Emily Hudson

10 April 2014

Abstract

Population ecology studies the perpetual vacillation of populations in the ecological world. By understanding the concepts of how populations change in response to the environment, better steps can be taken to monitor and predict both population sizes and the effects of the fluctuations. In particular, the response of the small freshwater plant Spirodela polyrhiza to the increase of salt concentrations, specifically increases of CaCl and NaCl, was studied. The knowledge gained in this study can be effectively applied to the study of freshwater ecosystems. It was hypothesized that the higher the concentration of salt, the more negatively the growth rate will be affected. It was also hypothesized that increases in CaCl would more negatively affect the growth rate than increases in NaCl. Various salt concentrations were increased in small populations of duckweed and then were allowed to proliferate for a week. The final population count and growth rates were then analyzed. The results showed that the increase in salt concentration negatively affected the growth rate of S. polyhiza, however, there appeared to be no significant difference between the effects of CaCl and NaCl on the growth rates of the populations. Large concentrations of salt may impede the plants ability to successfully function properly. Therefore, salt concentrations negatively impact the plants growth rate.

Introduction

The world is an incredibly dynamic place. The environment, landscape, and all of the world’s inhabitants are in a constant flux. This concept provides the foundation for the study of populations, or population ecology. Population ecologists observe and analyze changes in population size by investigating how the interactions between the populations and the surrounding environment influence those changes (Molles 2013).

        If a population has unlimited resources and no competition or predation, it has the ability to show exponential growth; nothing will hinder the individuals from continuing to proliferate and from the offspring surviving to reproduce. Realistically, though, resources are not unlimited and competition or predation may be present.  The cap on a population size is due to limiting factors that stunt the continued growth of the population, such as the lack of a particular resource. Carrying capacities, which are the maximum numbers of individuals that an environment and its resources can support, dictate the size of the population when it stops growing exponentially (Molles 2013).

        This experiment studied the effect that the availability of nutrients had on the population growth of the small, freshwater plant Spirodela polyrhiza (S. polyrhiza), more commonly known as duckweed. Duckweed is generally found as dense floating mats in ponds and ditches (Driever et al. 2004), and it prefers conditions with high phosphorous and nitrogen concentrations (Van der Heide et al. 2006). Often, the dense duckweed mats on the water’s surface inhibit the growth of other freshwater plants, such as algae and macrophytes, by restricting the oxygen supply and availability of light. Such inhibitions of growth may greatly reduce the overall biodiversity of the ecosystem. Organisms higher up on the food chain  may also feel the indirect effects of the algae and macrophyte population changes (Van der Heide et al. 2006).

        Understanding the dynamics of population growth for species, such as S. polyrhiza, is vital to the study of populations and their impacts on the environment and vice versa. By understanding how to manipulate the population size of duckweed, the growth and proliferation of other organisms may also be controlled and monitored.

        The purpose of this study was to determine the effects that increasing a highly concentrated and slightly concentrated nutrient in the growth medium, sodium and calcium respectively, would have on the population growth rate of the organism. It was predicted that an increase of 0.1 g of salt, NaCl or CaCl, would negatively affect the growth rate of the duckweed, an increase of 0.05 g of NaCl or CaCl  would have a slight negative effect on the growth rate of the duckweed, and an increase of 0.01 g of NaCl or CaCl would hardly affect the growth rate of the duckweed. These predictions were made based on the concept that plants generally respond to high salt stress by stunting both growth rate and plant size (Maas and Grattan 1999).

Materials/Methods

This experiment took place over a time span of seven days within the Ecology and Evolution lab on the campus of the University of Nebraska-Lincoln. On the first day, 27 plastic 100 mL cups were obtained.  Each cup was filled with 50 mL of distilled water and 50 mL of a Swedish growth medium. The contents of the Swedish growth medium can be found in table 1.

Table 1.  Swedish growth medium concentrations

The 27 cups were then divided into three groups. One group, the control, had nine cups while the other two experimental groups also had nine cups each. NaCl was added in small increasing increments of 0.01 g, 0.05 g, and 0.1 g to one of the experimental groups. Each amount was added to three cups. CaCl was added in the same manner to the other nine cups. No salt was added to the control cups (table 2).

Table 2. Amount of salt added to each sample cup

Group	Control	NaCl	NaCl	NaCl	CaCl	CaCl	CaCl
Cup numbers	Cups 1-9	10-12	13-15	16-18	19-21	22-24	25-27
Amount of salt added	0 g added	0.01 g added	0.05 g added	0.1 g added	0.01 g added	0.05 g added	0.1 g added

After all of the solutions were made, six fronds of duckweed were added to each of the cups and the cups were then placed under a light with a cycle of 18 hours on and 6 hours off for one week.  After the duckweed populations were allowed to grow for one week, the fronds were counted and the amount of water loss was calculated and noted. The results were then statistically analyzed by ANOVA.

Results

Our results supported our hypothesis because the addition of 0.1 g, 0.05 g, and 0.01 g of NaCl F(3, 14) = 5.57, p = 0.0099 (Fig. 1), as well as the addition of 0.1 g, 0.05 g, and 0.01 g of CaCl into the growth medium negatively affected the growth rate of the S. polyrhiza, F(3, 14) = 12.55, p = 0.000295 (Fig. 2).

Figure 1. The averages of 0.1 g, 0.05 g, and 0.01 g of NaCl and CaCl added to the 50:50 water and Swedish growth medium was compared to the control group, showing the number of fronds of Spirodela polyrhiza within each cup.

In addition to ANOVA, t-tests were performed in order to determine the significance of each individual experimental group compared to the control group.  The 0.01 g NaCl (p = 0.01975), 0.01 g CaCl (p = 0.01835), 0.05 g CaCl (p = 0.00004989), 0.1 g NaCl (p = 0.0003722 ), and 0.1 CaCl (p = 0.0002885) all displayed significance when compared to the control.  However, the 0.05 NaCl (p = 0.1499) appeared to have very little significance.  

Discussion

Comparable to much of the research that has been done on the effects of salts on S. polyrhiza population growth, our data indicate that the addition of NaCl and CaCl have a significant effect on the growth of the population.  The results indicate that the duckweed responded negatively to the addition of the salts, causing them to die and/or display brown spotting and streaking.

The death of the duckweed plants, as well as the brown spotting and streaking that appeared on their fronds, was likely due to the high salinity of the environment.  According to Maas and Grattan (1999), plants usually respond to high environmental stress (in this case, the environment being the salt in the growth medium), by stunting their per capita growth rate and frond size. Yilmaz (2006) confers that high salinity environments significantly inhibits the growth rate of the duckweed. High salinity environments cause hypertonic cellular environments, and the plant’s cells shrink and may ultimately die. High salinity environments also disrupt the homeostasis of the plant, as well as negatively affect the metabolic rate (Yildiztugay 2014).

After the S. polyrhiza was allowed to grow for one week, there appeared to be a significant difference in the number and condition of the fronds between the control and experimental groups.  Even the smaller concentrations of the salts that were added resulted in a significant decrease in the population growth rate in comparison to the controls group’s rate, which suggests that the environment heavily influenced the capacity to which these plants could grow.

When the t-tests were performed in order to compare each individual concentration to the control, all of the concentrations except for the 0.05 NaCl exhibited significance.  This odd result could be due in part to chance and/or human error in the data collection.

The chlorine within the salt compounds could have affected the results of the experiment. In order to increase the concentrations of the sodium and calcium, the nutrients had to be added as salts. As the sodium and calcium concentrations increased, so did the chlorine concentration.  Therefore, the sodium and calcium alone may not have caused the brown streaking and spotting on the S. polyrhiza fronds; the chlorine may have played a role as well.  

If this experiment were to be replicated, three factors would be taken into consideration. First, it may be possible that a drastic increase in the amount of salt added could potentially wipe out the duckweed population. This experiment showed that even a minute amount of these compounds could start to kill the plant; which is evident in the quantity of brown streaks and spotting on the fronds.  Therefore, if the environment increased in salinity, the stress would be extremely overwhelming to the duckweed, which may result in a sharp decrease in the per capita growth rate and the size of the plant. A similar experiment must be conducted in order to determine a range in maximum and minimum salt concentrations that the duckweed would be able to live in.  

Next, the amount of solution in the cups would also be taken into consideration if this experiment were to be repeated. It is possible that the brown streaks and spots on the S. polyrhiza fronds could have been attributed to the lack of regulation of the evaporation rate. By keeping the amount of liquid stable, evaporation would be eliminated as an outside factor that could alter the results. If the experiment were to be repeated, we would ensure that the solution volume stayed the same by adding water to the cups in order to negate the effects of evaporation.

Lastly, the significance between the increases of calcium and sodium would be analyzed. It would be interesting to further investigate the differing effects that calcium and sodium have on the plants.

This study is relevant to areas outside of the lab as well, especially when discussing the effect of salt on roadside plants.  According to Hudler (date unknown), when salt dissolves in water, the sodium and chloride ions separate from one another and are readily absorbed through the [plant’s] roots.  Therefore, when snow containing salt is plowed off into the roadside landscapes, the salt absorbs a great deal of the water that would otherwise be available to the roots of the plants.  When there is a loss of water and oxygen, the plant’s potential to grow declines.  Overall, it is clear that road salt  has a massive effect on the population growth of plants on the side of the road.  

In conclusion, the addition of the salts had a significant effect on the growth rate and size of the duckweed fronds.  The results collected in our study are in agreement with Maas and Grattan (1999), which suggested that high salinity environments would negatively impact a plant’s growth.  The data acquired from both of these studies will therefore provide insight into what the ideal environment for a duckweed plant is.    

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