Vibrating Rulers

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Objective

SWBAT record the vibrations and sounds a ruler makes when force is applied to it.

Big Idea

Students will conduct a simple experiment that has them holding a ruler down and applying force to create vibrations against the table. Students will notice a difference when the ruler is positioned at different lengths.

Setting the Stage

1 minutes

Materials:  Rulers

Students will work in teams as they observe what happens to a ruler when it vibrates against a table. The students will try holding the ruler (hanging off the table) at different marks and record what it looked and sounded liked when it was pushed upon and released.  The students will end the lesson with a discussion about their results.   

Our district has not moved toward implementation of the NGSS yet.  However, sound waves is a concept that is in our current curriculum.  I am pushing my students toward the full NGSS expectations of both light and sound waves.  Since it is above what the district requires, I am can push the students to go beyond the expectations.  Below is the district Grade Expectations for this unit.

Grade Expectations:

S1-2:7 Students demonstrate their ability to EXPLAIN DATA by…
  • Developing a reasonable explanation based upon observations (e.g., I found out…).
S1-2:29 Students demonstrate their understanding of Sound Energy by…
  • Investigating different objects, observing and describing the vibrations of those objects and the sounds that are made.

Science Concepts:

      a. Sound is caused by vibrating objects.

Engage

5 minutes

The students will gather on the carpet. They should bring a clipboard and a pencil.

"Before we get started, I want to review three vocabulary words with you.  The words are vibration, pitch, and volume."

I go over these words to make sure that they remember the meanings and to highlight them before we get into the testing phase of the lesson.  By discussing these at the beginning of the lesson, I am encouraging and reminding them of terms that they can use in their writing.  This intentional teaching, is a way that I encourage students to use precise science words in their writing.  

"Today we will be experimenting with rulers.  You will be using rulers to make nosies through vibrations."

The NGSS expect students to understand that vibrating matter can make sound.

"Has anyone ever put a ruler on the edge of the table, pushed down on it, and then released it?  What happen when you did this?"  Today you are going to conduct an experiment that has you using a ruler in this way."

 

Explore

20 minutes

You will need to hand out the following Sheet to each student.

The directions are on the sheet but I will introduce the task and model how to hold the ruler on the edge of the table.  This way my visual learners will understand how to compete the task.

"You will each need a ruler and a recording sheet.  You can work at your assigned table spot.  You will hold the ruler like this.  Then you will push it down and release it.  After you have done it a few times, record your observations on the table.  You will then repeat it at the 2 inch mark and the three inch mark.  It is important that your record what you are seeing, hearing, and feeling. " 

Our district curriculum expects that students Investigate different objects, observing and describing the vibrations of those objects and the sounds that are made.

Explain

10 minutes

I gather the students back on the carpet to discuss their findings.  I ask them to explain their findings and to share any interesting things that they noticed.  This is a great opportunity to incorporate the terms pitch and volume into the conversation.  The modeling of the use of specific vocabulary will help reinforce the definitions and encourage the students to use the words in their writings and conversations.  

"I would like to discuss some things you found out today during your exploration.  Who would like to start?"

If none is mentioning vibrations, sound, pitch, and/or volume, I will incorporate it into the students conversations about their results.  

 

Elaborate

5 minutes

I will play the following video for the class.  I want them to see how a vibrating ruler can change pitch and volume.  Once they are done watching it, I will ask them to fill out the following sheet (see resource in evaluate section).  

I want the students to be able to use their learning from their explorations and the video to answer some questions about today's task.  

Evaluate

5 minutes

"I would like you to partner up and work on this sheet together.  I want you to discuss your answers before your write anything down.  Make sure to use the vocabulary wall and incorporate the science vocabulary words into your writing."

I am looking that students demonstrate an understanding that the frequency of the ruler’s vibrations is affected by the length of the part extending over the edge of the table. They will also observe that changing the length of this part causes the pitch of the sound to change: more length produces sounds with lower pitch and less length creates sounds with higher pitch.