Now You See It, Now You Don't... Dissolving Matter

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SWBAT demonstrate that some matter may seem to have disappeared when it is dissolved, but it is still there.

Big Idea

Students will compose a written paragraph to explain why salt dissolves in water and soil does not.

Lesson Overview

5e Lesson Plan Model

Many of my science lessons are based upon and taught using the 5E lesson plan model: Engage, Explore, Explain, Elaborate, and Evaluate. This lesson plan model allows me to incorporate a variety of learning opportunities and strategies for students.  With multiple learning experiences, students can gain new ideas, demonstrate thinking, draw conclusions, develop critical thinking skills, and interact with peers through discussions and hands-on activities.  With each stage in this lesson model, I select strategies that will serve students best for the concepts and content being delivered to them.  These strategies were selected for this lesson to facilitate peer discussions, participation in a group activity, reflective learning practices, and accountability for learning.

Lesson Synopsis

The Now You See It, Now You Don't...Dissolving Matter lesson takes one class period. Students activate their prior knowledge by using the Give Me Five strategy to generate a list of properties to describe salt, soil, and water. Student use these properties to investigate how water and salt, and water and soil interact. Through an experiment, students identify substances that can and cannot dissolve. They make predictions, observations, and draw conclusions when stirring the substances. After completing their investigation, students reflect on their experiences using a series of questions which are later used in a guided discussion with the whole class.  I introduce key vocabulary terms relevant to the mixtures the students make.  I have them interact with the words by connecting their observations to the investigation of salt and soil in water and writing sentences to demonstrate their understanding of it.

Next Generation Science Standards  

This lesson will address the following NGSS Standard(s): 

PS 1-1 Develop a model to describe that matter is to small to be seen. 

PS 1-3 Make observations and measurements to identify materials based on their materials.

Why do I teach with this lesson?

I teach the Now You See It, Now You Don't...Dissolving Matter lesson with a guided inquiry activity to help students develop inquiry skills as they are investigating particles too small to be seen in matter. Many of my student have very limited background in science as the elementary school's within my district do not formally teach science prior to my students entering the 5th grade (the middle school). I find it important to provide guided inquiries that build their vocabulary and understanding of concepts in order to facilitate scientific thinking for future inquiry lessons. In this lesson,students investigate how some substances can be absorbed by water and others cannot. This investigation supports the notion that matter is neither created nor destroyed when it undergoes a change. By exposing and engaging students with an investigation to model that matter is too small to be seen, I am providing them with a foundation that will support their experience in the next lesson when they conduct an investigation to prove a substance that may have been seemed to disappear, really does still exist. 

Scientific & Engineering Practices

Students are engaged in the following Scientific and Engineering Practices

2.) Developing and using models: Students create a model of salt and water to demonstrate and describe how particles are too small to be seen.

8.) Obtaining, Evaluating, and Communicating Information:  Students use their observations and vocabulary terms to write a compare and contrast paragraph to explain their investigation findings.  Paragraph frames are used to help students compose a scientific written response and further develop their ability to communicate information from collected observations and data.

Crosscutting Concepts

The Now You See It, Now You Don't...Dissolving Matter lesson will correlate to other interdisciplinary areas.  These Crosscutting Concepts include:

2.) Cause and Effect:  Students use two different models to explain how and why some forms of matter can dissolve in water and other forms cannot.

6.) Structure and Function: Students develop a model that illustrates some structures of matter have particles that are too small to be seen, but still serve a function. Salt in many solutions functions as a preservative.

Disciplinary Core Ideas

Disciplinary Core Ideas within this lesson include:

PS1.A Structure of Matter:  Matter of any type can be subdivided into particles that are too small to see, but even then the matter still exists and can be detected by other means.  A model showing that gases are made from the matter of particles that are too small to see and are moving freely around in space can explain many observations.


Classroom Management Considerations

  • Importance of Modeling to Develop Student Responsibility, Accountability, and Independence 

Depending upon the time of year, this lesson is taught, teachers should consider modeling how groups should work together; establish group norms for activities, class discussions, and partner talks.  In addition, it is important to model think aloud strategies.  This sets up students to be more expressive and develop thinking skills during an activity.  The first half of the year, I model what group work and/or talks “look like and sound like.”  I intervene the moment students are off task with reminders and redirecting.  By the second and last half of the year, I am able to ask students, “Who can give of three reminders for group activities to be successful?” Who can tell us two reminders for partner talks?”  Students take responsibility for becoming successful learners.  Again before teaching this lesson, consider the time of year, it may be necessary to do a lot of front loading to get students to eventually become more independent and transition through the lessons in a timely manner.


For time management purposes, I use “lab rats roles” I introduce these roles this at the beginning of the year. I model each role and provide students' opportunities to practice each role with a group during an investigation or lab.  It has proven successful within my classroom keeping students engaged and on task.

Each student has a number on the back of his or her chair, 1,2,3,4 (students sit in groups of 4)and displayed on the board.  For each explore activity, I switch up the roles randomly so students are experiencing different task responsibilities which include: Director, Materials Manager, Reporter, and Technician.  It makes for smooth transitions and efficiency for set up, work, and clean-up. 


5 minutes

I start class by placing a container of water at each table group.  I instruct students to open their interactive notebook and say, "Give Me Five physical properties to describe the water you see." I ask them to discuss and write this list as a group.  Then I ask each group to share the physical properties to describe the water. I tell students to add properties to their list that they do not have.  By doing this, my students develop their list to further scaffold their understanding.  

Next, I place a container of salt at each group and ask them to repeat the process by discussing physical properties and Give Me Five physical properties of the salt.  I ask for shares and display these on the board.  Again, I call on students to share the physical properties of salt with the class and encourage other students to add properties they do not have to their list. I write their responses on the board. I want them to note the properties of each substance and recognize how their composition may affect how they react with other substances.

Finally, I hand them a container of soil and ask them to follow through with the same strategy, listing five properties of soil We share the physical properties of soil aloud and my students add properties to their list if they did not have them.

I use the Give Me Five strategy to activate students prior knowledge on physical properties. Since this unit started with properties of matter, I anticipate students will easily apply their knowledge to the substances salt, soil, and water.  I ask for five properties to encourage students to think more critically about possible physical properties rather than just thinking of one or two of them.  In addition, allowing students to collaborate provides them the opportunity to elicit ideas from and prompt one another to be active participants.



25 minutes

After identifying physical properties of water, salt, and soil, I instruct students to open their interactive notebook.  Then, I move students' attention to the standards board and call on one students to read it aloud:

"Today we will observe how water reacts when a substance is added to it by creating a model to investigate this reaction."  I tell them we are using the the substances salt and soil throughout the investigation. 

I use these materials because each one reacts differently to water, salt is known as a solute so salt particles separate and spread out evenly in the water, which is the solvent. Soil particles are big and small; therefore most of the soil settles at the bottom of the water (solvent).

Guided Inquiry

I review the lab rats' roles and task card procedure with my students. Then, I instruct students to set up their working station according to the task card procedure. Students take two clear containers and fill them each with one cup of water. Next, they add two tablespoons of salt to one container of water. Following that set up, they add two tablespoons of soil to the second water filled container.

Once each container is set up, I ask them to predict in their notebook about what will happen to each substances in water when it is stirred and share with the class. 

At this point, I move them into stirring each container, observing the reaction, writing what they notice in their notebook: water and salt, water and soil.

With their recorded observations, I post the following guiding questions on the board and ask students to draw a conclusion about the investigation by writing a response to each one.

  • Why do you think on the salt was absorbed by the water?
  • Why do you think the soil was not absorbed by the water?
  • Do you think the salt disappeared? Why or Why not?
  • Have you created a solution?  If so, describe what it is.

These questions and their responses are used as part of our class discussion as I guide them through drawing a conclusion based on their outcomes.


25 minutes

Reflecting On and Explaining Our Investigation

Once groups have completed the task card investigation, I tell them to keep their interactive notebook open and I ask student volunteers to share their observations of what they noticed in the investigation. I note their key words by writing them on the board.  I am looking for words that relate to the texture, actions/ behavior, color, etc.  Next, I ask them to think of other things in their life this investigation reminded them of. (Examples might include kool-aid, lemonade, iced tea, coffee, hot chocolate etc.) This question helps them personalize the investigation by connecting their own experiences with it. Finally, I hand out a pre-made cardstock sentence frame "When___________, I  _________ (describe what happened)." to each group and ask them to construct a statement together for when the soil and salt were added and stirred into the water.  I ask the lab rats' reporter from each group to share with the class and I post on them board as I move on to bringing specific key terms to students' attention.

Using a premade sentence frame helps my students clearly compose a scientific written response and further develop students’ capacity to communicate/interpret information presented as data. 

sentence strip

Connecting Vocabulary to Our Investigation

Now, I hand out a vocabulary graphic organizer to the students and point out the words dissolve, solute, solvent, and solution.  I ask them to say the words with me out loud as this gives them an opportunity to practice hearing and saying the terms. This practice is beneficial to special education students and English language learners as they develop their academic language. 

I have students share their written responses from their investigation and I connect the key terms to their findings to further explain why salt and soil reacted differently to the water.  Salt particles are so small that they dissolve, or separate, and spread out evenly in the water. The water molecules able to absorb them because they are so small. In this case, water is the solvent, or substance another material is being dissolved in. Together, they make a solution which is a mixture of substances that spread out evenly and do not settle. On the other hand, with soil, particles are too big; therefore, most of the soil settles at the bottom of the water (solvent).


As we make connections, I explain how they are filling out each section (statement, explanation,investigation connection, illustration) of their vocabulary chart graphic organizer.   In the statement box, students are writing a sentence using a vocabulary word from the box. A statement is written about salt and soil separately. Then, students write an explanation  using a word(s) on why salt dissolved and soil did not.  In a third box, illustration, students are instructed to draw a picture and label with vocabulary words to illustrate soil and then the substance salt.  In the last box, students are instructed to use terms from the vocabulary box and write a connection from the investigation.


5 minutes

In the remaining time, I wrap up this lesson by handing out a homework assignment that asks them reflect upon their experience and outcome during their investigation. I further explain that they are using their observations, evidence, and vocabulary from the lesson to compare the models of salt and soil solutions. I provide students with a paragraph frame to construct this written piece.

Using a paragraph frame will help students, especially my English language learners and special education students, compose a scientific written response and further develop thinking and writing skills to communicate/interpret information presented as data.

The next day, I collect these written pieces to check for understanding.  I am assessing their understanding on the fact that salt has not disappeared, it has dissolved. And although the particles are too small to be seen, they are still present. I am looking for evidence from their investigation to support this notion.