Scientists Measure with Care

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Objective

SWBAT demonstrate the basic measures of length, mass, volume, and temperature by estimating and measuring objects and recording the information.

Big Idea

Without standard practices and units of measurement, scientists would not be able to ensure the validity of their results or communicate effectively with the scientific community.

Engage

10 minutes

Even though my students are older, they still enjoy a good read-aloud. I like to incorporate read-alouds in my class when they are appropriate. The beginning and/or end of a lesson usually provides a good time to do so, as it can be a great way to connect content to literature. 

I start this lesson with a read aloud of the book, How Big is a Foot, by Rolf Myller. (If a copy of the book is not available to you, you can watch a video read aloud on Youtube.) The story is about a king who wants to build his wife a bed for her birthday. He measures the dimensions needed for the bed with his feet. When he has the bed built by a carpenter's apprentice, it is way too small, which angered the king and resulted in great trouble for the apprentice. Throughout the course of the story, we realize that the apprentice used his own feet, which were smaller than the king's.

After reading the story, I ask the students to reflect on what we have already learned that scientists do, and to think about what this book may have to do with the practices of scientists. After giving them about a minute to reflect on their own, I have them use their laptops post their ideas to a Padlet that I have created ahead of time. (For low-tech classrooms, this can also be done using sticky notes and sticking them to a wall or whiteboard.)

We read through everyone's responses and try to decide, as a class, the focus of today's lesson, based on the read-aloud. I circulate throughout the room, listening to student conversations and select a student who has correctly identified that scientists must measure properly. I ask them to share their ideas, confirming that today's lesson will address the need for scientists to measure accurately.

Explore

30 minutes

I pass out the advance organizer worksheet and direct students to decide whether each statement on the page is true or false.  They write their answers under the "Before Watching" column, placing a star next to each answer that they are not too sure about. This will help to provide focus as they view the Bill Nye Video, "Measurement" (below).

I explain that we are about to watch a video on the topic of measurement. As we watch, it will be each student's job to revise their answers, selecting true or false in the "After Watching" column. For every statement they think is false, they must rewrite it to make it true, using specific evidence from the video. (Students are familiar with the term "Evidence" from the Inference and Evidence lesson we have completed earlier in the unit.)

Explain

60 minutes

As students watch the video, I quietly set up stations throughout the classroom. (I have prepacked several plastic bins with all of the supplies they will need for each station, so I only need to place the bins in several locations throughout the room.) 

Once the video is over and students have had 3-5 minutes to complete the advance organizer, they are directed to look around the room, where they will notice that several stations have been set up for today's activity. I point out each station, identifying the materials they will work with. I am careful to use the correct terminology (triple balance beam, graduated cylinder, etc) while pointing out each station, in order to expose students to and model the use of academic vocabulary.

I pass out the measurement station packets and we go over the directions as a class, highlighting important steps that they will need to focus on and/or remember as they work. I let the students know they they will NOT complete the last page of the activity just yet. They should stop just before that page. (We will address that later in the lesson.)

After addressing any questions, I put the students in groups of four have each group select one station as their starting point, making sure there is only one group at each station.

As the groups work through the stations, I circulate throughout the room, asking questions such as:

  • "How can you be sure your measurement is correct?"
  • "How does your estimate compare to the actual measurement?"
  • "Explain the process you are using to measure."
  • "How might this process be different if you were measuring something much (smaller, larger, heavier, etc)?"
  • "How did you check your measurement for accuracy?"
  • "How did your estimates change as you got more practice measuring (mass, length, volume, etc)?"

Elaborate

20 minutes

As a class, we share out our data for several of the stations. I have one student serve as the scribe, recording everyone's measurements on a large chart on the board. Once we have collected our class data, I prompt the students to identify outliers or disagreements in measurement (rounding, incorrect units, etc) and to explain why there may be disagreements in the data we collected. If there are large discrepancies in the data we have collected, I select 2-3 students to remeasure the given object in front of the class (under the doc cam, if size permits) in order to get a more accurate measurement.

Finally, I pass out copies a variety of articles for the class to read. Each article describes how a simple measurement error led to wide-scale problems. I have each group read one of the articles and then orally summarize their reading for the class. The purpose of this activity is not to close read or to focus on summarizing skills, but rather to read for relevancy and to help students realize how simple errors in measurement are not just a problem in the lab, but can lead to massive, real-world problems.

Articles:

Evaluate

5 minutes

The students will compete the reflection questions located on the last page of the measurement station packet. They will tear this out of their packet and turn it in for me to assess. Ideally, the students have provided a thorough response to each, identifying the purpose of proper measurement in science. Many will answer he questions by referring to scenarios or information presented in the video, which is fine. It provides a context which is easy for students to understand and to relate to science, so I don't mind if they use it in their responses. They also turn in their advance organizers for me to use as evidence of learning.

I also have the students complete the "What do Scientists Do*?" paper in their science journals. This allows them to summarize their learning and provide a place to refer to later if they need additional prompting or support.

*The "What do Scientists Do?" paper is used throughout the unit. It is best to have students keep it in their science journal or another place where they can return to it throughout each lesson in the unit. We add to it as we build understanding and study each trait of a scientist.