How are Mass and Weight Different?

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Objective

SWBAT explain what mass is and how it's different from weight.

Big Idea

Knowing the difference between mass and weight is important for understanding how gravity works.

Lesson Overview- 5 E Lesson Plan

5 minutes

Unit 3: Gravity

Lesson 3: How Are Mass and Weight Different?

5E Lesson Planning:

I plan most of my science lessons using the BSCS 5E Lesson Model: Engage, Explore, Explain, Elaborate, and Evaluate. For a quick overview of the model, take a look at this video.

I use this lesson model because it peaks the students' interest in the beginning during the "Engage" portion and allows for the students to actively participate in the investigations throughout the subsequent steps. The “Evaluate” component of the 5E Lesson Model can be used in many ways by the teacher and by the students.

A great resource for lesson plan frameworks and explanations is the Community Resources for Science. The 5E Lesson Template and Planning Prompts come from this website. (Link to these resources).

Unit Overview:

In this Unit students will do some investigations about gravity. They will learn about how the planets stay in orbit around the Sun and will re-create Galileo’s pendulum experiments. They will also learn about Sir Isaac Newton’s work and his Laws of Motion as they relate to the idea of gravity.

Lesson Overview:

In this lesson, students will be learning about the difference between mass and weight. We will do this by first learning a song and then measuring the masses and weights of the objects we used in the previous lesson. 

Materials needed:

  • wiffle ball
  • tennis ball
  • ping pong ball
  • golf ball
  • paper
  • aluminum foil
  • cardboard
  • other small objects that are similar in size and shape but have different masses ( examples: pens, pencils, erasers, etc.)
  • spring scale
  • balance scale and mass weights

Next Generation Science Standards:

The NGSS standards that will be covered in this unit/ lesson are:

5-PS2-1. Support an argument that the gravitational force exerted by Earth on objects is directed down.

Disciplinary Core Ideas:  This lesson aligns to the Disciplinary Core Ideas of PS2.B: Types of Interactions  The gravitational force of Earth acting on an object near Earth’s surface pulls that object toward the planet’s center. (5-PS2-1)

Crosscutting Concepts:

Cause and Effect:  Cause and effect relationships are routinely identified and used to explain change. (5-PS2-1)

Science & Engineering Practices:

Engaging in Argument from Evidence

Engaging in argument from evidence in 3–5 builds on K– 2 experiences and progresses to critiquing the scientific explanations or solutions proposed by peers by citing relevant evidence about the natural and designed world(s).  Support an argument with evidence, data, or a model. (5PS2-1)

Engage

10 minutes

I show the students the following video of the Mass vs. Weight song. I give each student a copy of the Mass vs. Weight Lyrics so that they can learn the song and so they can use any information from the song to support their learning. Since this concept is a challenging one for most students (and even for most adults) I want to give the students a fun and easy way to remember what we are learning.

We then write the following terms and definitions in our Science Notebooks:

Mass, Weight, grams, kilograms, Newtons, scale, and balance. (insert photo of student notebook)

I remind the students that we learned how to use the spring scale and balance at the beginning of the year and that we would be using them in the investigation today. (I do a quick review with the students on how to use these tools).

 

 

 

Explore/Explain

30 minutes

I tell the students that they will be measuring the mass and weight of objects from the previous lesson:

  • wiffle ball
  • tennis ball
  • ping pong ball
  • golf ball
  • paper
  • aluminum foil
  • cardboard
  • other small objects that are similar in size and shape but have different masses ( examples: pens, pencils, erasers, etc.)

I give them a Mass Vs. Weight Object data collection sheet  to glue into their Science Notebooks.

I tell them that they will need to record their data on the worksheet and that the units we will be using are grams for the mass and  Newtons for weight. I make sure that they know that the balance scale is used for measuring mass and the spring scale is used for measuring weight.  (I model again how to use both of the tools so that the students are ready to perform the task).

I have the students work in their science groups to measure their objects and tell them that they should take turns with the tools so that everyone gets some practice. 

I make sure to walk around to check that everyone is completing the investigation and recording their data. This is also an opportunity for me to evaluate how the groups are working together and that they are using the tools appropriately. 

After about 15-20 minutes I ask the students to finish up their data collection and I check to make sure they have all had enough time to finish measuring all of the objects. We record the data on a large poster so that everyone can check to make sure they are close to the measurements everyone has recorded. Here is the Mass and Weight poster.

 

Elaborate/Evaluate

25 minutes

I make sure to clarify anything that students noticed while they were measuring the objects and I ask them the following questions to answer in their science notebooks to help support their thinking:

How are mass and weight related?

Compare and contrast mass and weight. 

What instruments are used to measure mass? Which are used to measure weight?

How would you describe the difference between mass and weight to a first or second grader? 

I have been using Webb's Depth of Knowledge to develop questions for my students and work towards making these questions at a level 3 or 4. Here's an explanation about DOK.

To review the difference between mass and weight, I show the students the following YouTube video

For this lesson I am evaluating the students' work based on my observations. I take some notes about how each students is working in their groups and I look at their Science Notebooks to see that they are recording their data and taking notes. At the end of the unit I will check each student's Science Notebook for completion and will grade them based on a rubric.