# Mixtures: Characteristic Properties - Phase Change (day 1)

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## Objective

Students will use a computer simulation to understand the particle model of matter.

## Teachers' Lounge

Purpose of Lesson:

The purpose of this lesson is for students to use a PhET Simulation to gain an understanding of the Particle Model of Matter.

Simulations are great teaching tools, not only because they show what can't otherwise be seen but also because they represent the scientific meaning of models. By now students are experiencing scientific models through all sorts of representations, and now I'm growing their understanding to include the very important scientific idea that models represent dynamic systems. Dynamic systems change. So today, by using the simulation, students are also changing the inputs and as a result the outputs of a system model.

5 minutes

Learning Goal:  Discover how particles in matter react to energy.

Opening Question:  How does heating a substance change it?

The most common answer to the question is "It gets hot."  The second most common is "It melts."  I think these answers show that kids are thinking very much at a bulk level and not at a molecular level.  Today's lesson will be all about shifting that viewpoint.

Students record their opening question on their learning goal sheet and are ready to start class 3 min after the bell has rung.  I reward students who get started early with ROCK STAR SCIENTIST tickets.

## Hook

5 minutes

This States of Matter video is boring but awesome!  It includes a ton of great information all given in a flat British monotone. To combat this, I show the video, but stop it at different points to talk about what the students already know.

The purpose of showing this video is to access prior knowledge and give them a chance to see the particle model of matter before using the PhET model and that experience is valuable because when the students get to the PhET Simulation, they have some understanding of what they are looking at.

## Understand and Describe the Problem

10 minutes

The purpose of this section is for students to understand what they are going to be doing during the activity and what success looks like.  I tell the students that they will be using a PhET Simulation on the computers and answering some questions on the worksheet.

To start I have the students look at the worksheet and answer the first two questions.  This is a great time to give multiple examples of solids, liquids, and gases and listen to students preconceived notions. I like to ask the students what the particles are doing inside the substance.  The biggest misconception that the students have at this point is that the particles in solids aren't moving and that gases are not made out of matter.

This is a great time to pull out these misconceptions.

## Obtain and Carry out a Plan

25 minutes

I like to introduce the students to the PHET simulations, showing them different aspects that they will be able to experiment with later.  It is really important to lay out the ground rules when kids are on computers.  For example, I tell students that the must remain on the first page of the simulation until their work is complete and then they are free to experiment.  Students that are not following this direction are asked to leave the computers and make up the work later.  Below is a screencast of how I might introduce this.

Once students have had a brief introduction, I turn them loose to complete the work.  As students are working I walk around and keep an eye on the computers to make sure that students are on task.  Before students turn in their work I check the questions to make sure that their answers are written at the appropriate level.  Once their work has been checked students are free to experiment with the PHET simulation.

Below is a video of a student and me having a discussion about the PHET simulation.

## Closure

3 minutes

Closing Statement: "Today we looked at how energy changed the particles in matter.  Tomorrow we are going to investigate if this is characteristic for different substances."

Closing Question: "How did energy change the particles in matter?"

Closure depends greatly on timing and is not as easy to plan in advance as opening.  You can find more information about how I manage closure here.