Grades 3-5

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Let’s Get Loud

The Big Idea You’ll use water and straws to generate different sounds, then make a pan flute out of milkshake straws. Finally, you’ll get to yell into a decibel-meter and find out how loud you are - using math the whole time to create funky music! Supplies Bedtime Math provides: You provide:

★ Milkshake straws: 8+ per kid

★ Measuring tapes: 1 per kid

★ Scissors: 1 per kid ★ Markers: 1 per kid ★ Rolls of masking tape ★ Paper or plastic cups: 1 per kid; half-filled

with water, to start ★ Free sound meter app for a smartphone or

computer (e.g. Decibel 10th for iPhone) ★ Free keyboard/piano app (for bonus)

Key Prep: ★ Fill 1 paper or plastic cup for each kid halfway with water. ★ Make your own pan flute to use as an example during the activity.

What’s the Math?

★ Measuring length ★ Comparing and sequencing lengths ★ Simple relationships between variables

Grades 3-5

2

Kickoff

Intro to the kids: “Did you know that no one can hear you yell in outer space? That’s because there’s no air! When we make sound, we’re actually rippling the air in waves. Today we’re going to test 2 math ideas about sound: the pitch, how high or low the sound is, and the volume, how loud it is.”

A Watery Whistle (5 minutes)

Intro to the kids: “The strings or pipes of a xylophone or a guitar play different musical notes because they’re different lengths. We can see how this works with a milkshake straw and a cup of water.”

1. First, have everyone take 1 full-length straw and practice blowing across the top of the straw, rather than through it. When they do it right, they should hear a musical note.

2. Next, each kid puts a straw into their cup half-filled with water. 3. Tell the kids to blow across the top of the straw as they move it

up and down in the water. Ask the kids:

★ “What happens to the sound? Why?” ★ Talk about how the length of the column of air relates to the pitch

– low or high notes – just like piano strings or xylophone bars. Bonus (optional): Ask the kids:

★ “Why does this happen?” ★ See if they can explain that shorter pieces produce sounds with

shorter wavelengths, which are higher in pitch.

4. Have everyone drink or pour out the water in their cups for the next activity!

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Be the Pied Piper (25 minutes)

Intro to the kids: “Now we’re going to use this idea to make our own pan flutes!”

1. Hand each kid 7 more straws, a measuring tape, a marker, and scissors.

2. Using a measuring tape, each kid measures and marks his/her 8 straws with a line at the following lengths (1 length per straw):

o 9 inches o 8 inches o 7 1/8 inches o 6 3/4 inches o 6 inches o 5 3/8 inches o 4 3/4 inches o 4 1/2 inches

3. Kids draw an X on the part of each straw past the marking – this

is the piece they will throw out. 4. Then, kids cut each straw at the line they drew, and put their

completed flute pieces into their cup to keep track of them.

5. The kids test the sounds of their straws: they hold each straw with one end pointing up and blow gently across the top.

Ask the kids: ★ “Do the straws sound the same?” ★ “Which straws made higher notes?”

6. Using masking tape, kids tape over one end of each straw so no air can escape.

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Ask the kids: ★ “How does the sound change when you cover one end?” ★ Answer: It drops by 1 octave! 7. After taping the ends, kids put

the straws in order of length from longest to shortest, with the longest on the left.

8. The top open ends should all be lined up.

9. Help kids tape across the straws to hold them together.

10. Now kids blow across the top to make music!

Ask the kids:

★ “How does the sound from the straws change with length?” ★ Answer: Shorter straws make higher notes. ★ “In math, the way 2 or more things change with each other – like

the pitch and the length of straw - is called their correlation. When the temperature outside goes up, what else goes up?” (e.g. thirst; eagerness to go swimming) “And what goes down?” (e.g. layers of clothing)

Bonus (optional): If you have a tuned instrument handy (guitar, keyboard, smartphone app), you can use that to identify the notes the kids’ pan flutes play (A, A#...), and then write the notes on the tape.

Grades 3-5

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Be Loud (15 minutes)

Intro to the kids: “Did you know that you can use numbers to measure noise? Sound is measured in decibels. Let’s use a sound meter to find out how loud YOU are!”

1. Roll out 10 feet on a measuring tape, lock it, and place it on the floor. Kids gather at one end of the 10-foot measuring tape, while you stand at the other.

2. Open up one of the suggested free sound meter apps. 3. The musicians play their flutes one at a time, 10 feet away from

your sound meter. Watch and compare the meter readings!

4. Now try voices! Kids take turns standing 10 feet from the meter and talking, while a partner watches the meter to see the range of readings and the peak sound.

5. Then, one volunteer holds a long, loud note on “ah”. Everyone notes the decibel level.

6. Then the hollerer walks towards the meter while holding that loud note.

7. See if the next yeller can get louder! NOTE: Encourage them not to screech – they’ll actually be louder if they belt instead.

Ask the kids: ★ “What happened to the decibel reading as people got closer?” ★ “Unlike an inch which is always the same amount, decibels change

with distance for the same sound: they drop as you stand farther from the noise, and rise as you stand closer.”

★ Cool fact: when you go up 10 decibels, you double the loudness!

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===A Touch of Class

To the kids: “Did you ever realize there is so much math in music – and that it’s just like the math you see in class? Your book might ask:”

★ “Which is longer, 1/8 inch or 1/2 inch?” (Answer: 1/2 inch.) ★ “If you have 3/4 inch and cut off 1/4 inch, what’s left?” (Answer:

2/4 inch, which is 1/2.)

Kids can take home their pan flutes to explore music and math even more!