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SWBAT understand that matter is made of molecules and molecules behave differently depending on the state of matter.

Big Idea

Molecule motion is imperative for understanding the basics of liquids, solids and gases and their transitions.


5 minutes

Teacher Tip: This lesson introduces students to the idea that matter is composed of tiny parts called molecules. Students will analyze various examples of molecules for each state of matter and will then create a definition of a molecule using this visual information. MS-PS-3-2 is addressed throughout this lesson as students are making connections between the arrangement and motion of the molecules and the specific state of matter they exist within.

To begin, students will make observations by completing the prompts on the student notes sheet and observing the images of molecules found at the top of the notes sheet. 


Looking at the pictures, make observations.

I see…

I notice that…

I wonder if…

After 4-5 minutes of students working independently, I ask students to share their responses with the class, writing down any valuable responses on the SMARTBoard. 


15 minutes

Students now receive images of molecules for all 3 states of matter and their molecules. They will make more detailed observations about the molecules in relation to one another using their notes sheet and each other as a reference. 


Look at the pictures of each state of matter (liquid, solid and gas) and make observations about each one specifically.


I see ______________ .              

I notice ______________ .


I see ______________ .

I notice  ______________ .


I see ______________ .

I notice  ______________ .

Students are expected to specifically describe what they see. (How are they arranged? in lines? rows? randomly?)


5 minutes

For a bit of personal and independent reflection, students now take about 5 minutes to individually respond to the following questions on their notes sheets: 

Answer the questions below based on your observations above.

  1. In which state of matter were the molecules closest together?

  1. In which state of matter were the molecules furthest apart?

  1. In which state of matter were the molecules lined up in neat rows?

After about 5 minutes, I ask 1-2 students to share their responses with the class. Should any student disagree with a response, I give them the opportunity to explain why they are not in agreement. They must provide their reasoning for this.  


10 minutes

Students now receive a sample of each state of matter (cup or water for liquid, a wood block for solid, and a cup of air for gas). Using the samples, they complete a chart by making observations and connections between the behavior of the samples and the descriptions of the molecules. 

Now, take your observations one step further. Observe the liquid, solid and gas sample and make connections to your molecule observations.


5 minutes

The last part of the lesson asks students to sketch the molecules for liquid, solid and gas on an index card as a form of an exit ticket. This gives them the chance to recall what they've learned in this lessons well as strengthen their understanding of the molecule arrangement for each state of matter. 

Should your students need extra help, assign this student homework reinforcement