Mixtures: Characteristic Properties - Reteach/Extend

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Objective

Students will be able to review their knowledge about characteristic properties and use that knowledge in an authentic lab situation.

Big Idea

What is the substance? How do you know?

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Purpose of Lesson:

The purpose of this lesson is to help students solidify their knowledge and ability to use characteristic properties as a method to identify substances.  Part of this lesson is a review done as a game show and part is an inquiry lab.

Ready...Set...Engage!

3 minutes

Learning Goal: Review our knowledge of characteristic properties and use that knowledge in the lab.

Opening Question: If a mystery substance was placed before you...how would you try to identify it?"

Students write in response to the question. We'll return to these responses.

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

This is a really neat video on The Properties of Water. I only show about the first 2 minutes for this class because the information on molecular structure, surface, tension, and polarity is not in our learning goals!  But I love to stop the video and point out the part on solid, liquids, gases and the section on density. Used wisely, this is a great wrap-up video. 

Reteaching

10 minutes

I love to use game shows for review because it's fun and engaging but the students are still learning the information.  This site has more information about different game formats you can use in class for review.

For this lesson, I used the game Un-Wheel of Fortune.  First I picked a phrase that the student teams would be guessing.  My phrase today was

"Characteristic Properties can be used to identify substances."  On the board I write out the phrase using just lines instead of letters.  Just like in the game Wheel of Fortune, the students will be trying to guess the phrase.

Then I broke the students into 6 teams.  In my class this is really easy because my students are already set up at desks. 


I like to have the teams come up with team names that have something to do with our science content.  Not only is this fun, but it is an additional way to uplift concepts.  

Then I ask the questions.  You can either go around the room and ask each team a question separately, or set each team up with a bell and let them ring in when they have the answer.  If they get the answer wrong or partially wrong they cede the points to the next team.  

After each question the teams earn a point and have a chance to guess a letter for the phrase.  The teacher fills in the letters.  Any team can try to guess the phrase during each term.  The team that guess the phrases gets an additional 2 points.

  1. Name the characteristic properties we studied in class (boiling point, magnetism, solubility, and density). If students name extra characteristic properties those are simply extra points. (color, odor)
  2. Name items that are NOT characteristic properties. (mass and volume)
  3. Name four items that are less dense than water. (wood, sulfur, alcohol, ice)
  4. Name four items that are MORE dense than water (metal, corn syrup, salt water, rubber)
  5. Describe ways that particles respond to energy.
  6. What are some parts you need to include in a graph?

At the end of the game, the winner is the team that has the most numbers of points.  

In the video, I show how you might set up your board and run the game.

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Extension

20 minutes

In the Characteristic Property Lab students apply what they have learned about the characteristics of substances to identify a substance. This is more of an inquiry lab than many of my experiments since the students are using their own knowledge and planning their own procedures (SP3). Like all inquiry labs, this experiment can get a little hectic because students are deciding on what and how to do their inquiry. Managed correctly, inquiry labs are more motivating and engaging for students. For more on how to manage them, please see my reflection.

I prompt the students before they begin that they should be working like scientists today. I want them to seriously observe and describe the substance. The point is not to get done first...the point is to get the most evidence for your argument.  

The substances that I use in this lab are sulfur, iron filings, sugar, alcohol, water, oil, and sawdust. I put the substances in the back of the room in numbered containers. Then I give each pair of students a number. This way the students are all working with different substances. I like to put the lab supplies at a table in the center of the room. This controls the flow of student movement and allows me to keep an eye on the glassware. If I see a student about to begin an inappropriate experiment, I can quickly find them and investigate. I generally don't let students go to far in the wrong direction without first offering them a cue to getting back on track. 

I also do not give them sentence starters for the conclusion to the lab. I'm looking to see whether I can start taking that scaffold away. It is my expectation that they continue to use the rigorous science discourse model although it doesn't have to be the exact same words. (The anchor charts are still in the room, I just don't point them out to the students.) I'll be checking on this when I review their labs.

Closure

3 minutes

Closing Statement: "We have been studying characteristic properties and how they can be used.  Our next unit will be about using these properties to separate mixtures."

Closing Question: "What are the most important things to know about characteristic properties?"

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.