Straight from the Heart

Cheryl L. Trammell             Delano Elementary School
                               3937 W. Wilcox Street
                               Chicago IL 60624
                               (312) 534-6620

Objectives:

(These objectives are adaptable for all grade levels.)

The main objectives of this mini-teach are to define and demonstrate the 
functions of the heart; observe the vibration of a match due to the pulsation of 
blood in the wrist; to construct a simple stethoscope and use it to listen to 
your heartbeat; to measure your heart rate (pulse); to compare your heart rate 
with your partner's heart rate; and to calculate the number of times your heart 
beats in one hour. 

Materials Needed:

Heart Model           Vibration Observation        Stethoscope Models
one-half pear         modeling clay                surgical tubing
per student           paper match                  2 funnels per model
surgical tubing                                    modeling clay             
plastic spoons
scalpels
"heart" vocabulary

Strategy:

Heart Model
1.  Have students turn pear upside down and remove seeds.
2.  Cut out two hollow openings at the top and two larger ones directly
    under them to represent the four chambers in the heart.
3.  Introduce the largest artery and the largest vein by inserting surgical 
    tubing in proper positions.
4.  Discuss function(s).

Vibration Observation
1.  Insert the match into a very small piece of clay (the smaller the better).
2.  Flatten the bottom of the clay.
3.  Place your wrist, palm side up, on a table.
4.  Place the clay on your wrist, and move the clay around on the thumb side
    of the wrist until the match starts to slowly vibrate back and forth.
5.  Count the number of vibrations that the match makes in one minute.

Stethoscope Models
1.  Have students work in pairs.
2.  Cut the hoses for the stethoscopes into approximately 3 feet lengths.
3.  Set out all the material on supply table.
4.  Prepare a sample stethoscope.  Slide the hose over the end of each funnel.  
    Use clay to hold funnel in place.
5.  Instruct students to be quiet because it will be very hard to hear the 
    sound of a heartbeat if there is a lot of background noise and talking.
6.  Have one student place one end of the funnel on his ear while the second 
    student places the other funnel near the left side of the chest.
7.  Have students listen to the heartbeats of themselves and partners using 
    stethoscopes and compare rates.
8.  Calculate the number of times your heart beats in one hour.

Performance Assessment:

At the conclusion of the mini-teach, students will be able to answer the 
following questions:

     Heart Model:
      1.  How many chambers are in the heart?
      2.  What are the names of the chambers?
      3.  What are the functions of the chambers?
      4.  What is the name of the protective covering of the heart?
      5.  What is the name of the largest artery?
      6.  What is the name of the largest vein?

     Vibration Observation:
      How many times does the match vibrates back and forth with a
          regular heartbeat?
          (For adults it will vibrate 60 to 80 times in one minute.
          The vibration for children is from 80 to 140 beats per minute.)

     Stethoscope:
      1.  Did you hear the "lubdub" sounds of the valves snapping shut with each 
          heartbeat? 
      2.  How do you think the stethoscope works?

Conclusions:

Students will understand the functions of the heart and that as the heart 
contracts, blood is forced through the blood vessels.  The blood moves at a 
rhythmic rate causing the blood vessels in the wrist to pulsate.  All blood 
vessels have this throbbing motion, but the vessels in the wrist are close to 
the surface of the skin and can be felt more easily.  The movement of the blood 
under the clay causes it and the match to vibrate. 

The students will also understand through the use of the stethoscope that sound 
waves pass along the tube to the ear and that the funnel collects the sound 
made by the beating heart.