Microscope Mania (Part 1/2)

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Students will be able to provide evidence that all living things are made up of cells.

Big Idea

Students read a text about the Cell Theory through the lens of the NGSS Crosscutting Concepts and look at a variety of substances (both living and non living) under microscopes!

Introduction and Connection to the NGSS and Common Core

This is the first lesson in this Cells Unit.  Students are introduced to Cell Theory as they read text through the lens of the NGSS Crosscutting Concepts in order to make deep connections and generate questions they have surrounding the content.  Then, students look at living and non living things under microscopes.  On Day 2 of this lesson, students support claims with evidence as they write a scientific argument.

This lesson is specifically designed to meet the following NGSS and Common Core Standards:

MS-LS1-1  Conduct an investigation to provide evidence that living things are made of cells; either one cell or many different numbers and types of cells.

CCSS.ELA-LITERACY.WHST.6-8.1.B  Support claim(s) with logical reasoning and relevant, accurate data and evidence that demonstrate an understanding of the topic or text, using credible sources.

CCSS.ELA-LITERACY.RST.6-8.10  By the end of grade 8, read and comprehend science/technical texts in the grades 6-8 text complexity band independently and proficiently.

Science and Engineering Practices:

The NGSS states that students at any grade level should be able to ask questions of each other about the texts they read, the features of the phenomena they observe, and the conclusions they draw from their models or scientific investigations (SP1). In addition, any education in science and engineering needs to develop students’ ability to read and produce domain-specific text (SP8).  In this lesson, when students read text for information and draw connections beyond the text to the cross cutting concepts, they do just that!  In addition, students have to write a written argument explaining if they believe a single cheek cell is a unicellular organism (SP7)

Crosscutting Concepts:

Specifically, this lesson ties to the idea that that phenomena that can be observed at one scale, may not be observable at another scale.  As students recognize that cells may become visible with the use of a microscope, they are able to connect to this idea of Scale, Proportion, and Quantity.

In addition, his lesson allows the students the opportunity to connect to all of the CCC's.  As they read, students make connections to each category and post their connections on sticky notes on a large class graphic organizer.

Connecting to the Essential Question: What are you supposed to learn today?

5 minutes

As this is the first day of the unit, provide students with their Cells Unit Plan.  Explain that today is an exciting day because the students' focus changes.  With a new unit comes a new Essential Question.  Remind them that this EQ will be their focus for each lesson during the unit.  

So, each day when they cross the threshold into my classroom, I ask them, "What are you going to learn today?"  Students should always refer to this EQ as their focus.  Explain that the new EQ for the Cells Unit is, "How do cells contribute to the function of living organisms?"  Show students that this EQ is easily available for reference both on the front board and on their Unit Plan.  Remind the students that the skills listed on the unit plan are the targets they have to meet in order to reach mastery.  

Let students know that today's lesson will focus on Skill 1:

"I can provide evidence that organisms are made of a single cell or many cells.".  

Have students silently read the skill along with the bulleted list below the skill and then give themselves a self-assessment score of where they feel they are at in their learning to begin this unit.  Students rank themselves on a scale of 1 - 4 (4 being mastery).  Explain to students that as this is the first day of the unit, there is nothing wrong with them feeling as if they are at a 1 or a 2. We will build mastery each day!

Mini Lesson: Cell Theory, The Ladder of Discourse, and Crosscutting Concepts

30 minutes

Students read the Cells and Living Things and climb the Ladder of Discourse.  (Please realize that the reading is something I wrote.  I refer to my daughter and reference some things that I have seen in my class.  Feel free to use the reading; however, any text that you have referencing the difference between living and non living things and the cell theory will work!  It doesn't have to be the same text I use.)  

The Ladder of Discourse is a strategy I use in my class to help students think critically as they read.  For middle school students, informational reading can just become words on a page.  The Ladder of Discourse is a way to help students recognize what they should be thinking about as they read so that they can gain an understanding of the text.  The levels of the Ladder of Discourse are "Tweets" (text to self connections), "Huh?'s" (questions or concepts they do not understand), "Found It" (finding answers to questions through context clues or finding science answers), and "Discourse" (combining ideas to think beyond the text).  The resource Ladder of Discourse: Description of Rungs provides background about the "rungs" students use when reading.  

For middle school students, thinking critically during reading is a challenging task.  However, being able to think beyond the text is key to real understanding of scientific concepts.  This "thinking beyond the text" is what we call the rung "Discourse".  I have found that the NGSS has provided us with an invaluable tool in the Crosscutting Concepts.  These provide students with themes that can guide their critical thinking.  When they read, students have out their Ladder of Discourse: Description of Rungs document so that they have a description of the Crosscutting Concepts next to them with the CCCs fresh in their mind.  As they read, they try to make connections to the CCCs.  This could be in the form of a statement, idea for an experiment, a prediction, or a question.  In order to do this, students have to slow down when they read.  Every 2 - 3 sentences they stop and think about what connections they are making to the text and they document their thinking by "talking to the text".

I have found that with the implementation of this strategy, my students depth of understanding from reading has dramatically increased.  As students read, they "talk to the text", to document what they are thinking.  

Notice in the picture below how the student wrote, or "talked", on her paper what she was thinking about as she read.  (I know you can't quite read everything in this picture - I just wanted to give you a visual of what "talking to the text looks like.  There are readable examples coming.  Keep reading to see them!)

After reading and "talking to the text" (writing down what they are thinking about as they read on their paper), have the students write down one of their "discourse" on a sticky note. On my board, I draw a chart with headings naming each NGSS Crosscutting Concept.  Students write their discourse on the sticky note and place it on the appropriate poster it connects to.  

Now, I will say, this strategy takes practice!  It is not a magical strategy that makes reading easy.  It is a tool, however, that provides students with a structure and thought process for critical reading.  If you stick with it, I promise you that you will see an increase in the depth of thinking your students demonstrate while reading.  As another tool to help with this strategy, I have included a resource called Ladder of Discourse Sentence Starters that I used with my students when I first began implementing this to get them thinking about the Crosscutting Concepts.  Have students use these sentence starters to help get them started!

Take a look at some of the ideas and questions that my students generated during this reading.  None of the comments on the sticky notes were stated in the text, it was all their own connections and conclusions beyond the text.  They are all ideas the students connected to because they were thinking about the Crosscutting Concepts as they read.  If you take the time to read each sticky note, I think you will see why I am so excited about this strategy.  Some of these sticky notes come from readers that have struggled.  I realize some of them aren't perfect, but the shear idea that these are the thoughts going through their head when they are reading serves as evidence that the strategy is making a difference.  As this is the first lesson in the unit, many of these are questions that they have generated.  However, through the Crosscutting Concept lens, I think you will see there is deep thinking and scientific connections in the questions they develop.

Scale, Proportion, and Quantity:

Energy and Matter:

Systems and System Models:

Cause and Effect:

Structure and Function:


Reflection: How do the NGSS Crosscutting Concepts transform the way students read?

After implementing the "Ladder of Discourse" strategy that asks students to use the NGSS Crosscutting Concepts to help them think beyond the text when they read, I was amazed with what my students are thinking about as they interact with text.  While I was feeling confident about the success of the strategy, I wondered how the students were feeling about their growth as a reader.  So, I pulled random students of all ability levels and asked them how the Crosscutting Concepts have changed them as a reader.  

I started to write a reflection that included the video of some of the students responses that is shown below, but I felt the students' words were too powerful for this video to not warrant a section of its own.  Listen to these 7th graders explain how they have changed as a reader as a result of the NGSS Crosscutting Concepts.  Consistent application of this strategy has truly been transformative.

Microscope Mania

45 minutes

Provide the students with the Microscope Mania Lab Document.  Set up microscopes around the room.  My school has a cart of microscopes so I set up 16 of them, but you could do this with much less than that if you had limited access to them.  When I set up this lab, I have eight stations with two microscopes at each station.  

The stations include:

  • Sugar
  • Cheek Cells
  • Elodea Cells
  • Onion Cells
  • Salt
  • Pencil Shavings
  • Skin Cells
  • Corn Starch/Flour

With the exception of four of stations, I prepare the slides for each microscope.  The four slides students must create themselves are the cheek cells, skin cells, elodea, and onion stations.  

While my students have used microscopes earlier in the year, I review some microscope tips with the students before beginning:

  1. Remember that you should never pick up a microscope!
  2. Moving the stage up and down helps bring images into focus.  
  3. Using the diaphragm to adjust the amount of light that gets through can help you see images more clearly.
  4. Only use the smallest two objective lenses!  For this lab, the smallest two lenses provides the best images (with the microscopes I have).  And, if students use longer lenses, I have had situations where they moved the stage up too high and touched the lens to the slide resulting in iodine getting on the lens.
  5. If you are having trouble getting your microscope into focus, ask me for help!  (I have found that middle school kids often will do this lab and not be sure if what they saw is correct.  Encourage them to ask for help during the lab.  Seeing the correct images is critical to understanding.)

Explain to students that they will work their way from station to station to examine the slides.  Show them where the 3 stations are in which they will have to follow a procedure to mount their own slides.  Emphasize to them that their goal as they look at the slides is to find Patterns.  Scientists look for patterns in data to make predictions about phenomena and find the causes of events.  In this lab, students should look for patterns in the images of living vs. nonliving things that they look at under the microscopes.  

Before moving to the next station, I ask students to stop and talk as a group about any patterns they saw in the following:

  1. Similarities/differences in the structures between the living and nonliving things
  2. Similarities/differences between structures of the cells of the living things that come from plants and the living things that come from animals

Allow students to move through each lab station.

The Microscope Mania Procedures that I post at the lab stations are included in the resource section.  It is important to note a couple of safety tips:

  1. Emphasize to students that when using the toothpicks at the cheek cell station that they only need to lightly brush the side of their cheek.  They do not need to poke or scratch their skin! 
  2. Throw away used toothpicks to prevent the spread of germs.
  3. When finished with the student prepared slides, students should rinse off slides before moving to the next station.

For more on the student work and completion of the lab document, see the lesson for Day 2!

Closure Day 1: Formative Assessment

5 minutes

As an exit ticket, have students complete the Formative Assessment slip.  Before the next class, sort the formative assessment slips into stacks of similar learners.  In the following day's lesson, I meet with these groups to provide specific instruction geared towards specific student needs.

This student includes some important elements required for mastery:

  1. She draws a diagram that includes pictures and labels that shows a living thing is made of cells, but sugar is only made of molecules.
  2. She includes a title that describes the purpose of her diagram.
  3. She states Part 1 of the cell theory in her caption.
  4. She states that the cheek cells are living and thus are made of cells.

**Caution:  Even with students that show mastery such as this, a follow up conversation needs to be had.  Many students begin forming the idea that living things are made of cells while nonliving things are made of molecules.  They can have the misconception that living things are not made of molecules.