Common core State Standards

  • ELA: 

    English Language Arts

  • W: 


  • 7: 

    7th Grade

  • 1b: 

    Write arguments to support claims with clear reasons and relevant evidence.

    a. Introduce claim(s), acknowledge alternate or opposing claims, and organize the reasons and evidence logically.

    b. Support claim(s) with logical reasoning and relevant evidence, using accurate, credible sources and demonstrating an understanding of the topic or text.

    c. Use words, phrases, and clauses to create cohesion and clarify the relationships among claim(s), reasons, and evidence.

    d. Establish and maintain a formal style.

    e. Provide a concluding statement or section that follows from and supports the argument presented.

Download Common Core State Standards (PDF 1.2 MB)


Common core State Standards

  • ELA:  English Language Arts
  • RST:  Reading Standards for Literacy in Science and Technical Subjects 6-\x80\x9312
  • 7:  7th Grade
  • 3:  Follow precisely a multistep procedure when
    carrying out experiments, taking measurements,
    or performing technical tasks.

Download Common Core State Standards (PDF 1.2 MB)


Common core State Standards

  • ELA:  English Language Arts
  • RST:  Reading Standards for Literacy in Science and Technical Subjects 6-\x80\x9312
  • 7:  7th Grade
  • 7:  Integrate quantitative or technical information
    expressed in words in a text with a version of that
    information expressed visually (e.g., in a flowchart,
    diagram, model, graph, or table).

Download Common Core State Standards (PDF 1.2 MB)

Making Sense of Density
Lesson Objective: Students perform a lab to explain why density = mass/volume
Grade 7 / Science / Lab Work
ELA.W.7.1b | ELA.RST.7.3 | ELA.RST.7.7

Thought starters

  1. How does the use of technology enhance student understanding?
  2. What strategies are used to check for individual understanding throughout the lab?
  3. What might be overlooked if Mr. Treadgold did not ask probing questions as each group completed the activity?

I love this lesson! My students have been engaging in it for 3 years now and they get so much out of it! I love showing how mass and volume are proportionate to density and watching their "light bulbs" go off. Thank you, Mr. T, for sharing this lesson.

Side note: Kent was also a great resource as I reached out to him when I first did this in my classroom.

Recommended (0)
What was the eye dropper for in the lab?
Recommended (0)
I found that I could use PVC pipe cut up in different lengths for the the cylinders. It is easy to cut and they fit in the graduated cylinders.
Recommended (1)
I love the idea of letting the kids work on excel to input data.
Recommended (0)
Mr. Treadgold, thank you for showing and sharing your investigative activity into density. Although the video was short, I couldn't discern if there was any "missed teaching opportunity" because like all the videos here on teaching channel, the public is not being shown how a whole lesson pans out. What I like about the way the ratio of mass and volume on the same axis in your graph is that it shows that the value of the density remains constant as a horizontal flat line. This is a good buy in. Traditionally, one would have students plot mass versus volume and get a diagonal line. And I like how this constant ratio is shown as a horizontal. Well done! I'm certain that your students benefit from your ample experience and depth of knowledge. Others don't have that luxury. Happy teaching!
Recommended (0)


  • Transcript for Making Sense of Density – Kent Treadgold

    Killer tracks under “Kent Treadgold”

    Hi, I'm Kent Treadgold. I teach

    Transcript for Making Sense of Density – Kent Treadgold

    Killer tracks under “Kent Treadgold”

    Hi, I'm Kent Treadgold. I teach 7th grade science at Explorer Middle School in Everett, WA. Today we're going to be exploring density in my classroom.
    “How many people think water is more dense? How many people think oil is more dense?”

    The challenge of teaching density to middle school students is that it's a very abstract concept and most of what they're used to dealing with is concrete and real and things they can feel and see.

    Prior to today, the students had only been introduced to the idea of density from sitting in their seats in the classroom and having me right up on the board density equals mass divided by volume. For 98% of them, that equation was meaningless. Today they're going to have hands on experience finding the density of these different objects and this is when they're going realize what the concept of density is really all about.
    Today were going to continue with the solid density activity that you started yesterday.
    Today when the students come in they will go in to their lab areas with their partners. They will then start measuring the mass of the four cylinders, they will then measure the volume of the four cylinders and they will start calculating the density.
    When you’re working with the cylinders we’ve got 4 different sizes, we’re going to have small, were gonna have medium, were gonna have large, and were gonna have Mr. T. Where would Mr. T go in this arrangement? Ok the biggest one is Mr. T I agree with that. Let’s go to work.
    (Classroom interaction)

    Today the students are going to be using computers to collect data. They open excel and they create the file. I used to create templates in excel where they would enter the data. Well I found it to be much more valuable to have the students create their own spreadsheet where they collect their data-- for them to enter the formulas and for them to create the chart. The single most important item that I want students to take away from today's activity is that density will not change as the size and shape of an object change as long as the material is the same material.

    After they've calculated the density, they call me over. This is a great time to just check to make sure the groups are in fact making accurate measurements and you can do a quick scan within a second or two of a group's data and see if they made a mistake or not. If the data looks good, at this point the students will then graph the data.
    “So the volume keeps on increasing, the mass keeps on increasing but the density stays the same because they are made of the same material.”
    When I first designed this lesson I was hoping that the graph itself would be the culminating point where it would be realized that density doesn't change as the sample size changes. I found as I was doing it with students that I needed to ask them some probing questions after they created the graph that would cause them to go back and look at their data, to look at the graph and figure out the answers to those questions.
    “The four cylinders are all made up from the same material what do you notice on the graph about the mass as the cylinders get bigger?”
    “The volume and mass both get bigger, but the density stays the same”
    After that one of the questions I pose involves slicing a cylinder lengthwise so let’s revisit number 6 before we do number 7, pick one of the cylinders. You take Mr. T and you slice it that way what size will it be? It’d be half, if we sliced it in half hollow what would it’s volume be? Half of what it was, excellent. So now we need to calculate the density. 1.14 which means? It would stay the same. You got it!
    And one of those questions will trigger that realization in almost every case and when that happens they are able to do the last step, which is just write a general rule for the density of any material.

    One of the great things about this lesson is that students are able to be successful no matter what their academic level is. I am hoping that students will realize the concept of density, and I’m hoping they arrive at it not through listening to me but through working on their own and with their fellow group members to arrive at measurements and arrive at answers to questions.

School Details

Explorer Middle School
9600 Sharon Dr
Everett WA 98204
Population: 919

Data Provided By:



Kent Treadgold
Science / 7 / Teacher


Teaching Practice

All Grades / All Subjects / Collaboration

Teaching Practice

All Grades / All Subjects / Planning

Teaching Practice

All Grades / All Subjects / Engagement

Lesson Idea

Grades 9-12 / ELA / Tch DIY


Professional Learning


English Language Learners


English Language Arts