Review 9: Converting Measurements Part 2

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Objective

SWBAT use ratios to convert measurement units between and across measurement systems.

Big Idea

Which reverse bungee jump was higher – 54.3 meters or 175 feet? Students practice comparing measurements withing and between measurement systems.

Do Now

5 minutes

See the Do Now video in my Strategy Folder for more details.  During this review unit, I have selected multiple choice questions that cover as variety of topics. 

To check the do now, I ask students what they think the most common wrong answer for the first problem is.  I ask students to raise their hands as I call out each letter.  This gives me a quick gauge of what students are thinking.  I am looking for students to quickly explain why someone would mistakenly select A. 9%.  What were they thinking?  What did they probably forget?  For the third problem I say that point A is 1 ¾, since there are four lines from 1 to 2.  I call on a student to explain why I am incorrect and to share the value of B. 

 

Guided Practice

10 minutes

After the Do Now, I have a student read the objectives for the day.  I tell students that they will be building on their work in Review Lesson 4 and continuing to use their foldable as a resource to convert measurements.  I’ll tell students to get out their foldables to use during the lesson.  I ask students why it is important to be able to convert measurement units.  Students will likely share about the importance of being able to change one measurement into different units when designing or building something. 

I call on a student briefly explain our strategy for converting measurements.  I stress to students that by using ratios we can see what units we have and what units we want to have and then change them.  I stress that for each problem students must create a ratio showing the relationship between the measurement units you are given and the units you want to convert to.   I have found that this strategy works better for my students than telling them to divide if they are changing from a “larger” unit to a “smaller” unit.  The ratio strategy also sets them up to convert measurements from metric to customary and customary to metric more easily.

We complete problem 1 and 3 on page 3 together.  For each problem I ask a student to use their foldable to find the relationship between the two units in the problem.  We set up a ratio and then set up the next ratio with what we know and what we are trying to find out. 

Students work on the other problems on page 3.  I circulate making sure that students set up ratios.  

Taking Conversions to the Next Level

20 minutes

For #7 a volunteer reads the problem and we answer the questions to the side.  I ask students whether the answer is A. 5.  I call on a couple students with different opinions.  I am looking for someone to mention that the two measurements are in different units so we first must create common units.  We solve the problem together.

Students work on problems on page 5 and 6 independently.  Before moving on to the next section, they check their answers with the key that is posted in class. See the Posting A Key video in my Strategy Folder for more information.

 

Comparing Measurements

10 minutes

I circulate to monitor student work and behavior as they work on page 7 and 8.  Again, I look to see that students are creating ratios to convert measurements.  If students are struggling, I ask them what the question is asking.  From there I have them identify what two units we are working with.  We create a ratio comparing the two units (ie. 1 meter/3.3 feet) and then set up what we want to know.  If a student is struggling I will have them change 54.3 into feet because the calculation will be less calculated.  Another option is to offer the student a calculator.  This way a student who is struggling with carrying out the operation will not be hindered in comparing the measurements which is the objective of the lesson.

If a student completes this section correctly I will ask them to brainstorm something they want to know the height/weight/capacity of.  Once they have determined an object I’ll ask them to get on a computer at the back of the room.  They need to look up the measurement of the object and then I’ll tell them to convert that measurement into a unit from the other system (for example gallons to liters).  They can use google to find the relationship between the two units.

Closure

15 minutes

See the Closure video in my Strategy Folder for more details.  I ask students to share strategies for (c) and (d) for #27 on page 6.  I am looking for students to set up a ratio that 1 inch/ 20 miles to help them determine the missing measurement.  I ask students to share strategies for #1 on page 7.  Is it more efficient to change one measurement into another? Why or why not?    

With the last few minutes have students complete the ticket to go independently.  See the Ticket to Go video in my Strategy Folder for more details.