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to Lesson Plans
(4th grade 50-60 min)
PURPOSE:
The student will use the harmless Madagascar cockroach to aid
in comparisons of size and relative ability in smaller species.
The student will use math skills to make comparisons to human
capabilities. The student will use previously learned skills in
measuring, massing, and predicting.
Science TEKS 4th grade
*Scientific inquiry 2a-e: asking questions, formulate and test hypotheses, collection formation, analyze and interpret information, draw conclusions and organize evaluate information
Math TEKS 4th grade
*Solving problems with addition, subtraction, multiplication,
division 3&4
*measuring 11
MATERIALS:
*male and female hissing cockroaches
*paper towels (roll)
*plastic petri dishes
*sewing thread, brightly colored
*clear tape
*pennies ( 50 per group)
*balance or spring scale, gram or milligram
*data sheet
*small ruler
*marker
MOTIVATION:
The best motivation would be to simply pull out a roach and let
the students begin to observe characteristics. Get a child to
touch the roach along the abdomen so that the roach will 'hiss'..
Another way might be to have the children predict how many pennies
one little roach could pull. After massing the roach, show by
conversions how many times its weight their guess would be. Then
follow with the activity.
ACTIVITY:
This will be done as a demonstration with student participation. The students need to lay out and tape to the table a long line of paper towels. Have one or two students to be in charge of adding the pennies. Have another student be in charge of marking on the paper towel when the roach moves 1/4 inch (or use 1cm if metric). Another student or students can be in charge of massing the roach and massing the pennies. The thread is to be tied with a nonslip noose at the end and placed over the head of the cockroach. The other end of the thread is taped to the bottom of the petri dish (without lid). Have the students decide how many pennies they would like to start with; probably one of the initial guesses. The student marks as the dish is pulled 1cm, and another penny is added. This continues until the cockroach can no longer pull. Have a student remove the pennies and count them while another student helps the teacher cut the harness off the roach and it is replaced into its cage. The pennies are then massed and the calculations done to compare roach mass to pulled mass and to determine how many times over the roach pulled. Then have the students calculate the comparable amount they would have to pull to be equal. This can then be repeated with another roach, wither the same sex or opposite sex for comparison of anatomy and ability.
SAFETY TIPS:
Although the roaches will not bite, they do have spurs for gripping
on their legs and can hurt or startle the children.
CONCEPT DISCOVERY:
The teacher should help the children to explore the roaches' adaptations
which allow them to pull so much material for their size. The
mathematical aspects include proportions. The teacher will probably
have to demonstrate the calculations. It is also necessary to
remind the students that this roach is considered an exotic species
and cannot be released into the surrounding habitat.
GOING FURTHER:
If the teacher has access to his or her own culture, then it may
be possible to have the students themselves conduct this experiment
in pairs or small groups. Also, various comparisons can be made:
small male versus small female; large male versus small male;
carpet versus paper towel surface; petri dish versus small can,
etc. It was also suggested that a version of this activity using
grasshoppers could be done in lieu of hissing cockroaches. The
grasshoppers are easier to catch and many students would feel
more comfortable holding them. Grasshoppers can be marked on the
dorsal side with model paint and them comparisons can be done
regarding jumping ability and distance.
CONNECTIONS:
History: students can research the arrival of the Madagascar cockroach
into the U.S. and what types of restrictions are placed on these
and other exotic species