Transcript Chapter 5, Section 1 Sounds in Vibrating Strings

Test Friday (Safety and
Collisions)
To the back of the room:
-Determine your Mass off egg and
compartment
-choose a spokesperson to explain your
design
-have your rubric out for official grades
-Typed components level 3 will be
accepted no later than tomorrow
morning.
warm up
Number your paper from 1-20
1. Mass
2. Time
3. Energy
4. Acceleration
5. Force
6. Applied Force
7. Work
8. Velocity
9. Net Force
10. Frictional force
11. Kinetic Energy
12. Force of weight
13. Gravitational Potential Energy
14. Acceleration
15. Acceleration due to gravity
16. Inertia
17. momentum
18. Pressure
19. Elastic Potential Energy
Content Objective:
SW be introduced to Big Idea #5 for the class,
and brainstorm ideas which can be used to
evaluate “Entertainment Value” for Chapter
Challenges.
Language Objective:
We will know the objective was met when we can
come to consensus on what will be needed in
order to develop and present a quality chapter
challenge.
Big Idea #5
The Properties of
Sound and Light
Demonstrate Wave
Behavior
Let Us Entertain You
Chapter Challenge pg 480
Brain Storm:
What are the qualities of an Entertaining
Presentation?
http://www.youtube.com/watch?v=8TrvKg1Xb2k
Pre test
Waves and Energy
A toy train with a mass of 1.0 kg coasting at .5m/s
overtakes and collides with a .25 kg cart moving the
same direction at .3 m/s. When they collide they lock
and continue forward.
1) Draw before and after momentum diagrams.
2) Is this elastic or inelastic?
3) What is the final speed of the carts?
Collect Projects
What’s on the test?
Content / Language Objective:
SW Investigate the variables which influence
the pitch of a vibrating string, being able to
write an explanation on how to change the
pitch of a stringed instrument, using words
learned during the investigation.
Chapter 5, Section 1
Sounds in Vibrating Strings
Pg 484
What do You See?
What do You Think?
Homework: due Monday
Read PT pg 486
CU pg 487 #4
PTG pg 490 #2,3,6
Honors:
Include
APP pg 488 #1-4
Investigate:
Read as class
Copy the data table on page 485
Team reader and other members:
Quietly read steps #1-4
Material Specalists:
Meet me in the back Once your set-up go to step #3
-Clamp
-cup
-Pulley
-string
- 500g mass
-meter stick
##3-4 10 minutes
#5-6 10 minutes (3 more masses)
In your Journal:
Frequency:
Number of vibrations (cycles)
occurring per second.
Units:
waves/s
cycles/s
1/s
Hz
In your Journals, draw the following graphs:
f
Tension
f
L
Draw what you think the curve of each graph would
look like. Quadralogue
Crucial Physics
Let’s Look at the String Equation!
Copy in your Journal
f=
_T___
4 mL
Grab a white board and marker
White board challenge #1
in your groups, place the units for each variable in the equation
and solve for the units for frequency:
T = kg.m/s2
m = kg
L=m
f=
_T___
4 mL
Class share, What are the units for frequency?
White board challenge #2
Now, looking at the equation, with your white board group,
predict what you think a Tension vs frequency and Length vs
frequency graph would look like
f=
_T___
4 mL
Class share
Pass out graph paper and fold in half
f
Tension vs frequency
T
-----------------------------------------------------------------------f
Length vs frequency
L
On your own, make the following table and using the equation,
solve for “f” make m = 1, L=1:
T
f___
4
8
12
16
20
f=
Graph it!
_T___
4 mL
On your own, make the following table and using the equation,
solve for “f” make T = 4 and m=1:
L
f___
1
2
3
4
5
f=
Graph it!
_T___
4 mL
You do:
Next to each graph you just drew, explain the
relationship between the two variables:
Stem #1:
As tension increases, frequency ……………………
Stem #2:
As length increases, frequency ……………………
Tape / staple into your journal
You do
In your Journal, write a summary explaining how
length and tension effect frequency of a
vibrating string
Do now:
1. Which of the following statements describes the
relationship between the pitch heard and the
vibration rate of a string under tension?
a) As the vibration rate increases, the pitch increases.
b) As the vibration rate decreases, the pitch
increases.
c) As the vibration rate increases, the pitch decreases.
d) The vibration rate and the pitch heard are not
related to each other.
2. Which of the following are the units for Frequency?
vibrations / s
cycles / s
Hz
1/s
waves / s