Molecules Move

14 teachers like this lesson
Print Lesson


SWBAT design an experiment that tests the effect of temperature on molecular motion.

Big Idea

Student-centered learning leads to deeper conceptual understanding. Let your students develop experiments to test the effects of temperature of molecular motion and you will see their passion and understanding unfold.

Do Now

5 minutes

I want to establish an understanding of students' alternative conceptions going into this lesson. According to a study performed by Johnson, 1988 and cited by the American Association for the Advancement of Science Project 2061 website, 21% of students think that water molecules in a glass are not moving.  

This probing question will establish a baseline that we can build off of during our lessons on this topic. Student reflections are a valuable formative assessment strategy that I use at the end of most lessons, because it allows me to assess how students ideas have evolved as they learn more about a topic.  They also illuminate the manifestation of new or promotion of preexisting misconceptions.  I can then coordinate lessons that challenge their beliefs.  

Do Now (written on board):

What are the water molecules doing in a cup that is sitting on an undisturbed surface?

This do now allows me to establish two things:

1) I can probe students' ideas about molecular motion, prior to teaching the lesson, to see what they recall from lesson 1.1.

2) The topic will be covered in class, allowing me to reassess their understanding of the same topic at the end of class.   I will ask them to provide evidence that supports their claims.

It is important that the Do Now is "memorialized" right away, as a class. I write the responses on the board but I don't allude to the accuracy of their statement. These statements are now present throughout our activity, and I will revisit them as a formative assessment at the end of class.

Planning and Carrying Out Investigation (SP 3)

10 minutes

I state that today we will be testing the following driving question:

"Do liquid water molecules always move at the same rate?" 

Again, I want my students to develop an ability to plan and carry out investigations (SP 3), but since this is a relatively new practice, I guide them by saying that they can model their design after the beaker and food coloring demonstration from yesterday.  

I then give out this graphic organizer that helps focus students' attention while they organize their investigation.  Additionally, they also have this handout in their notebooks that can be used as a reference.  Here is a sample of a student's entry.

Circulate around the room and help students with the challenges they may face with setting up experiments.  Once their experiments are approved groups can begin experimenting.  They should be sure to record their findings in their science notebooks.

Here is what it looks like as kids are carrying out their investigation:

Analyze Results and Modeling

20 minutes

Once students have collected the results from their experiments they should begin analyzing the meaning of their findings.  

Students should create models using pictures and descriptions to explain what they think is happening at the molecular level.  

Students can then deepen their understanding by viewing these American Chemical Society simulations, and take notes in their science notebook.


5 minutes

Checking for understanding is an important process that happens at multiple points of a lesson.  Since students are generally interpreting data, observations, simulations and processing other group members ideas, I want to make sure that individual students are grasping the most basic principles surrounding this topic.  As such, I give each student this worksheet to complete and circulate around the room, intervening/providing remediation where necessary.  

We then review their answers at the conclusion of class.  

To bring it all together, we discuss our post conceptions and compare them to our pre conceptions that were recorded on the board during the Do Now. This comparison is an important part of this lesson. 

Students are assigned this sheet to complete for homework.  

Video of Experiment

1 minutes

Teachers can use this video to review, remediate, show to kids who were absent, etc.