Guided Inquiry Based Lesson

Hi folks!  Here's to another lonnnng week and short weekend!  Please, one of you brainy scientist ezplain that phenomena to me!

This week's assignment was to perform a guided inquiry lesson from a list of movement activities.  I, being brave or stupid - fine line there, chose the one I knew least about - Pendulums.  As a child I was always in awe of them, and found myself like the Christmas Story kid mesmerized by them in a x-mas store display - wondering how and why it worked.....not really,   just amazed at watching the continuous motion  (Look at what music did for Frankenstein)

I was offered the question that would a heavier pendulum take longer to stop swinging than a lighter one.  Just like the Falling Bodies example, I, too, quickly shout out the wrong answer!!

first off  ; heres the experiment i stole:

Objectives:

1.      Investigating the behaviour or pendulums.

2.      Identifying variables that affect the “period” of the pendulum.

3.      Understanding that time and motion are related.

4.      Gathering and organizing data to make predictions.

5.      Concluding that the period of a pendulum and the frequency of its swing are related.

6.      Conducting controlled experiments.

Background Information:
Pendulum activities are excellent ways to develop the science process skills of Observing, Hypothesizing, Identifying and Controlling Variables, Predicting, Measuring, Recording and Interpreting Data, and Drawing Conclusions. They require simple, inexpensive materials, and lend themselves to cooperative groups. Language and Math skills are integrated throughout the activities.

The “frequency” of a pendulum is the number of swings it will make, back and forth, from its release position - in a unit of time. The frequency is dependent mainly upon the length of the string. As the length is decreased, the frequency increases. As the length increases, the frequency, or number of swings, decreases. The length of the pendulum is the critical variable that determines the number of swings a pendulum will make in a unit of time.

Any weight that is suspended of a string, cord, rope, or any other material that is free to pivot from an anchor or release point is a pendulum. Neither the weight at the end of the pendulum nor the distance the weight is displaced from its resting position affects the length of time it will take for the pendulum to make one complete swing back and forth.

General Guidelines:

1.      Journal entries must be made for every test or trial run as well as data charts.

2.      Group sizes work best composed of 3 or 4 members.

3.      Grade level: 4 - 6

4.      Time: 45 minutes per activity.

Materials per Group

·         4 pennies

·         4 paper clips, regular size

·         2 strings, the same length

·         1 metric measuring tape

·         2 pencils

·         1 scissors

·         4 Student Activity Sheets

·         4 Student Graph Sheets

·         1 Instruction Sheet called Building a swinger (4 washers may be used in place of the paper clips and pennies)

Materials For the Class

·         1 ball of string

·         1 number line

·         1 box of paper clips, regular size

·         1 role of masking tape

·         2 pennies for each group

·         1 timer, watch, or clock with a second hand (washers can be substituted for the paper clips and pennies 1 - 2 per group)

Procedure

1.      Show students a pendulum (a string with a tied on washer on the bottom, a tied on paper clip on the bottom, or a paper clip holding a penny which is tied on the bottom. Without labelling this as a pendulum, ask students what they could do with this “swinger” (swing it back and forth). Demonstrate how to swing it back and forth in your hand (you might play the recording of the “Syncopated Clock” at this time). Tell them that a weight (called a bob ) swinging back and forth on a string is called a Pendulum, or a swinger. Discuss how hypnotists use the swinging technique to make patients sleepy. Relate a swinging pendulum to the swinger on a grandfather clock. Have students predict how many times the swinger will swing in 15 seconds.

2.      Ask, “How can my pendulum be changed? What could be changed in the swinger system that might change the number of swings in a set amount of time?” (There are 3 variables that affect the pendulum’s behaviour: weight of the bob of the pendulum, the swing - position from which the pendulum is released, and the length of the string of the pendulum). Point out that anything you change in an experiment that might affect the outcome is called a variable. Ask, ”How will changing one of these variables affect the pendulum? How can we find out?”

3.      Set up a “Materials Station”. Direct students to send a person from each group to gather supplies. Pass out Student Activity Sheets, Directions For Building a Swinger, Graph Paper, and Data Charts. Review with students the directions and construct a sample pendulum.

4.      Discuss the procedure for doing the experiment. Ask, “Which variables need to be controlled to standardize the procedure?” Emphasize that it is important for everyone to do the test the same way:

a.       All desks or tables used as the base for the pendulum should be the same.

b.      Pencils need to be alike and taped to the table securely the same way (same amount of pencil sticking out over the desk edge, facing the same direction-with eraser end sticking out over the edge, same amount of tape securing pencils on the desk at the same position on the pencils).

c.       Swingers should be constructed exactly the same way, and hung on the pencils the same way.

d.      Amount of time for the swings should be the same.

e.       Method for counting the “swing” should be the same - when released, the swinger will swing away and then come back. That is one cycle . Each time the swinger comes back close to the point from which it was released, it counts as one “swing”.

f.       Swings should be released at the same height and angle - straight out and parallel to the table.

5.      Swing a demonstration pendulum for the students to observe. Count the swings out loud together. Give them time to practice swinging their swingers and counting (silently).

6.      Have a trial swinger test. Students should first predict, and then count the actual number of swings in 15 seconds. Repeat the process, saying “Go” and “Stop” each time to verify the results. Ask each group for their counts. (The counts should all be 12).

7.      Have students record their data on their data sheets. (This may be a good time to end the activity. Review students’ observations and conclusions the next day before beginning the next activities).

8.      Ask students if a new release position will affect the number of swings, and take a vote. Suggest that they experiment with the variable of release position. Instead of releasing the swinger straight out (parallel to the floor), release swingers at about a 45 degree angle. Reinforce the fact that all other variables must stay the same. Have students predict the number of swings; then conduct the experiment. Compare the results to the original experiment. (The number of swings should be the same).

9.      Ask students how to test whether weight will change the number of swings in 15 seconds. Double the number of objects on the end of the pendulum. Have them predict the outcome. Conduct the experiment, holding all other variables constant. Compare the results with the other experiments, and record the data. (The number of swings should be the same).

10.  Have students make new swingers of various lengths to test the variable of length. Label the length of each string. Remind students to again control all other variables (weight, release position, time, etc.) when they do the experiment. Ask for predictions for the number of swings in 15 seconds. Conduct the experiment and record the data. (Long swingers will need high anchor positions). Make a numbered line of the chalkboard, or hang up a pre-made line, numbered from 5-30. Each student, or group, should hang their swinger below the number on the number line that represents the number of swings their pendulum made in 15 seconds. Let everyone observe the swingers and discuss the pattern they make. (The number line should show a smooth curve along the bottoms of the hung swingers).

11.  Have students make a statement to conclude the relationship between the number of swings a pendulum makes in 15 seconds. (The longer the string -the fewer the swings; the shorter the string - the more swings the pendulum makes).

12.  Ask students to use their knowledge of swingers to predict the number of times a new swinger (of a length not used) will swing in 15 seconds. Provide additional strings and bobs to make new pendulums to test these predictions. An additional activity would be to have students predict the length for a pendulum to make it swing a designated number of times (You may want to save this for the next day).

13.  Review the variables that made no difference in the swings (release position, weight) and which did make a difference (length). Reinforce the relationship between the length and the number of swings (longer pendulums make fewer swings; shorter pendulums make more swings). Make up problems such as:

a.       If Tammy has a pendulum 15 cm. long and Frank has one 25 cm. long, whose pendulum will swing more times in 30 seconds? (Tammy’s).

b.      If a pendulum clock was running slow, how could you help to correct it? (Shorten the length of the pendulum, or the arm).

c.       If a heavy person and a light person both start to swing on a swing in a park at the same time, will they swing with the same frequency? (Yes).

d.      If you are swinging from an overhead bar, how could you increase your frequency of swings? (Shorten your length, by drawing your legs up to your stomach).

e.       Where have you seen pendulums in your environment?

14.  For bright students, challenge them to plot the points representing the length of each swinger and the number of times it swings in 15 seconds on graph paper. The lengths of the swingers go across the bottom of the graph -the X axis (the independent variable). The number of swings of the pendulums in 15 seconds are represented by the numbered lines going up the side of the graph - the Y axis (the dependent variable).

15.  Extension:
Hang two equal pendulums next to each other and connect them with a rubber band stretched across both strings or with a soda straw that has been split on each end. Make one pendulum start swinging and observe what happens. (They interact and one pendulum transfers energy to the other to make it start swinging). Ask what would happen if you moved the straw (or rubber band) up the pendulums or down? (It speeds up as the straw moves up; the swings slow down as the straw is lowered).

16.  Discuss the concepts of kinetic and potential energy in relation to these experiments. (The bob has all potential energy when held at maximum height; it loses potential and gains kinetic energy when released - and then reverses this, until it comes back to a resting position).

Now that that is out of the way!

My kids were really able to make these pendulums using assorted classroom materials  -  my personal favorite was the child who used my ear of corn egg-timer.  They were fascinated that they could build these REAL scientific instruments in such a primitive way!

After I cheated, read the results and practiced the experiment as i drove to work - YES  the kids results were the expected ones - the weight did not effect the freuency, however pointed out to my my Janeequuah that the size of the twine or string effected the bob!  This is what i LOVE about the guided inquiry...it answers specicfic questions - but opens the door for much more learning!!!!

What went well with my class was the desining and performance of the activity - but unfortunantly classroom management when working in groups is still a struggle.  The school was marred with many fights and disruptions last week which led to preoccupied chatter and lack of complete academic cooperation!

Next time i do this experiment, I will work on a grander scale - the kids ove to see bigger and better generally - so i can take this activity to the auditorium and dangle the pendulums from the overhead balcony as my pivot area - just focusing on not letting objects fly wildly about like an old zim-zam!!!!

My goal; however, was to answer a specific scientific question by creating a model and oberving and recording results - which was a SUCCESS and also a bonus that inferring was involved to come up with the WHY of the problem!

I apologize for no pictures -this week - cam is on the fritz again!  ciao for now!