Separating Mixtures: Problem Solving 1

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Objective

Students will be able to use scientific processes to plan, design and carry out a method for separating a mixture.

Big Idea

Create a flow chart model to guide you through a lab.

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Purpose of Lesson:

The purpose of this lesson is to let students investigate and observe their mixture and make a plan for separation.

Major Strategies to Watch for:

1) Structured discussion- Students use sentence starters to have a structured discussion.

2) Flow chart- Students make a flow chart to display their plan on how they are going to separate the substances.

Ready. Set. Engage

5 minutes

Learning Goal: Explore your mixture and supplies and create a separation plan.

Opening Question:  What characteristic properties are important to consider in a separation lab?

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.  

Follow the links to learn more about the beginning of class strategies and ROCK STAR scientist tickets

Hook

5 minutes

Hey Jude by Lyrical Flowcharts is an awesome video that shows using a flow chart to diagram the lyrics to that Beatles classic. Before watching it, I ask students if they know what a flow chart is and have any ideas of why to use them.  

About a minute into the video, I stop it and talk to the students about the purpose behind the flowcharting.  Why would someone flowchart?  What does it accomplish?  How does it help the listener understand the song?

Afterwards we watch the rest of the video...because...well, it's a really good song!

Understand and Describe the Problem

10 minutes

In this lab students will be given a mixture of sand, salt, iron filings, and wood shavings and be asked to separated it.  

I start this lab by giving the students the supplies they will be using.  Since they are planning their own labs this gives the students a chance to start visualizing how they will set up their experiment. At the same time I hand out the mixture so the students can start to do an observation and discussion.

 

 

 

 

 

 

 

  

 I ask students to start making a plan for figuring out what is in their mixtures and how to separate it.  For this conversation students are NOT responsible for writing anything down or turning in thoughts.  That will happen in the next section.  This section is all about brainstorming and building excitement.  

To help structure the student discussions, I put up our anchor chart for discussions and ask the students to use it in their planning. 

 

Obtain a Plan

20 minutes

I like to use flow charts to plan this lab.  This not only helps the students learn a different type of process map, but it allows them to make quick changes to their procedure. 

I use rectangles for mixtures, triangles for a lab process, and circles for single substances.  This is a flow chart I made as a model to show students how to make their own flow charts.  In this model the mixture is salt and sulfur.  I chose this because the students have already had the experience of working with this mixture.

Below is a video of a focus lesson I would do to show students how to make a flow chart. 

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After the focus lesson, I release the students to start building their own flow charts in teams.  Attached is a picture of student work.

Closure

3 minutes

Closing Statement:  Today we looked at our mixtures and supplies and made a plan.  Tomorrow will be the time to separate the mixture.

Closing Question: How are you going to start your lab tomorrow?

The purpose of this question is to give students a starting point tomorrow so that the students feel comfortable getting started right away.

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.

 

Ready. Set. Engage. Day 2

3 minutes

Learning Goal: Use your separation plan to complete the separation of your mixture.

Opening Question:  What do you think is going to be the most difficult part of the separation today?

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.  

This is a great opportunity for students to do some pre-thinking and get settled into class.  It is difficult for middle school students to go from class to class each day and just dive back into activities.  Questions like these can help put students back into activities they started yesterday.

Follow the links to learn more about the beginning of class strategies and ROCK STAR scientist tickets

Hook- Day 2

5 minutes

Because this will be a very independent lab, it is important to me to remind students of lab norms. I use LAB SAFETY Video - I Think School to do this.

After the video I have the students come up in groups with four important rules for us to follow. We put all the norms on the board and the students get to vote on the most important four. This year the lab norms my students had were;

- Wear goggles

- Stay calm.  Only get out of your seat to get supplies.

- Be considerate with supplies.

- Only do experiments that have been approved by the teacher.  

They great thing about collaborative norms is you can always add to them if you need to, but generally kids do a great job of setting them up and then it is easy to hold kids to the community norms.

Carry out Plan and Evaluate Results - Day 2

30 minutes

Now it is time for students to work independently to separate the substances. This is a tricky lab to supervise because students are all doing different things at different speeds. Invariably they are going to make mistakes and need help.  

I tend to spend this day on my feet running from lab to lab trying to help out. I ask the students to wait quietly at their desks while they are waiting for help. Often time other students at the table can help, but it is important to me that students aren't wandering around the room. One strategy I use to keep my eyes on the entire class is watchful helping. I make sure to approach the students from angle that allows me to see the other students in the room. When I lean down to help, I am always also scanning the room for potential problems. This type of mindfulness has a high effect rate on management and learning and is mentioned in Robert Marzano's book Classroom Management That Works.

To make this lab easy to grade, I have the students put their pure substances on paper towels and label them. At the end of the working period I can easily go around to each table and quickly mark off each substance. Don't forget to leave plenty of time for students to clean up! This is a messy lab and students need plenty of time to clean.

Closure

5 minutes

Closing Statement:  Today we completed our lab and separated the mixture.

Closing Question:  Were there any parts of the lab that you would do differently if you were going to do it again tomorrow?

The purpose of this question is to give students a chance to process and reflect on the lab they did and let them problem solve and evaluate their own results.  This question is best discussed with their partners and then shared out at the table. 

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.