Lesson 7 of 20
Objective: SWBAT determine that sound waves travels better through solids than air.
Setting the Stage
The students will work in teams today to conduct tests on conductivity. The goal being that they learn sound waves are better conducted through solid matter rather than the air. his activity as a foundational lesson for the next lesson in the unit. The next lesson will be creating cup phones. The concept of sound waves being conducted are key to understanding why the cup phone works.
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.
|S1-2:7||Students demonstrate their ability to EXPLAIN DATA by…
|S1-2:29||Students demonstrate their understanding of Sound Energy by…
I gather the students on the carpet for a quick discussion about the word conduct. I write the word on a sentence strip (it will later be added to our vocabulary wall) and lead a discussion about the word.
"Today we will be learning about conduction and how sound waves are conducted through solid surfaces and the air. Your job will be to determine if their is a difference in sound when you listen to the sound conducted through the air compared to through a table."
As I stated earlier I am choosing this activity as a foundational lesson for the next lesson in the unit. The next lesson will be creating cup phones. The concept of sound waves being conducted are key to understanding why the cup phone works.
The students work in teams of two or three for this activity. They need a metal spoon and a table. They use their science notebooks to make a prediction, record their observations, and draw a conclusion. They will use these notes to guide them in their discussion during science circle.
"I would like you to open up your science notebooks and set it up for today's entry. Today's focus is Conducting Sound Waves. You will tap a spoon on the table and record what you hear. You will then have your partner tap the spoon on the table and you will put your ear on the table (before your partner taps the spoon). Which test will conduct clearer sound waves? Before you do this, you must predict which test will conduct sound waves more clearly. Conduct each test a few times and then switch roles. When you are done write down if your prediction was correct or not and what you learned."
I have included a video of the introduction to this activity.
When students do both steps, they will begin to realize that they can hear the sound of the tapping spoon much louder when they put their ear on the table because sound waves are conducted better through solid surfaces than air.
The students gather on the carpet to discuss their findings. There may be a variety of ideas and results. The discussion should focus on the idea that sound waves are conducted better through solids and liquids than air and other gasses.
"I would like you to share what your found out or what you concluded from your results. Was there a difference in the sound? Why do you think this happened?"
Advanced Preparation: You need a metal hanger for each group of 4 and need to tie a string on each end of the hanger.
"I want you to hold the hanger upside down by the ends of the string and then bang the hanger against the table. Now repeat the procedure but, while holding the strings, put your fingers in your ears. Then bang the hanger against the table."
"Once you have tested the hanger both ways, I want you to use your science notebook and write what happened. Then I would like you to tell me what you learned about sound travel."
The point of this task is for students to discover that Sound travels better through a solid (string), than through a gas (air).
I use the Science Journal Scoring Rubric to score the students entries. Not only am I looking for the the criteria outlined in the rubric but I also check to see if they were able to connect the science circle discussion to the hanger task.
It is expected that students investigate different objects, observe and describe the vibrations of those objects and the sounds that are made.