AUTHOR(S), DATE:

Nicole VanderSal and Dr. Vernard Lewis, May 2004

GRADE LEVELS AND STATE STANDARDS ADDRESSED:

This is geared towards 8th graders, as the California education standards outline a unit on motion. However, this can easily be used for earlier grades by leaving out the velocity calculations, while still forming hypotheses, timing races, analyzing hypotheses, etc. To upgrade beyond 8 th graders, add more calculations on body lengths per time, converting from meters to feet, etc.

MATERIALS:

Invertebrates in individual containers with see-through lids

•  Best in multiples of certain groups, like 3 spiders, 3 beetles, etc.

•  Can use yogurt containers with pantyhose stretched over the top for a semi-transparent lid

• Track (picture)
• Vaseline: put on thin layer around lanes to keep organisms from climbing out
• Dry Erase Markers
• Stopwatches
• Calculators
• Pictures
• Measurements of average invertebrate body lengths
• Soft Tweezers

INTRODUCTION ACTIVITY (10 Min): 

Speed in general (picture):

(Click here for this handout)

•  Pictures of fast animals (cheetah, ostrich, antelope, etc)

•  Overall maximum speeds of these animals

•  Speed with respect to body length of these animals

• Biology of the invertebrates for class

•  Pictures and inverts in jars to pass around for the class to consider:

•  Number of legs, leg length, proportion of body to legs…

• Make hypotheses (write on board)

•  What will be fastest absolute and with respect to body size

PROCEDURE:

Form Groups : (5 min.)

•  Divide into groups for particular organism type (ie. spiders, cockroaches, beetles, etc.) Three or four groups probably, depending on time or material constraints

• Have groups look more in depth at their organism type and see if they think theirs will win or lose, and why (more in depth hypotheses)

Race Invertebrates in "heats" (30 min.) (picture)

• Groups should have optimally at least three students per individual organism

•  One students is in charge of dropping the invertebrate into the track

•  A second student monitors the invertebrate, tells the timer when to start and stop, prods the organism if needed, and marks (with dry erase marker) where the individual stopped if did not run all the way to the finish line (picture)

•  The third student is in charge of timing the individual

• Measure the length of the track from start to finish line (0.40 meters)
• Estimate body length of individual organisms with rulers (in centimeters for “body lengths per second” comparisons)
• Record times of individuals with separate stopwatches (this can be a limiting factor, but students can use watches with a second hand)
• Measure absolute distance each individual ran (to the dry erase mark) (picture)
• If racing multiple individuals at the same time (much more fun, and condenses time):

•  Try to dump individuals in at the same time

•  Do not start timers until your individual organism goes across start line

• Groups take turns running their type of organism (all beetles run together)
• Winner from each organism type will go to the final heat
• Race "winners" of the different types of organisms (fastest beetle against fastest spider)

Re-settle and swap data information (10 min)

• Write individual times recorded for the races (have students write it on the board as they go)

• Write estimated body lengths of the organisms they tested (this is just the body, and not including the legs

ASSESSMENT:

Wrap-up (5 min)

• Which animals were the fastest absolutely, and with respect to body length?
• Which factors of the individuals matter?
• Which hypotheses were supported, or rejected?
• What new things they learned, or were reinforced?

Calculations (during or after class, depending on time constraints)

• Average individual speed (distance/ time)
• Average speed with respect to body length (distance / (body length x time))
• Average speed across individuals of the same type (group average)
• Difference in individual speeds (within a group) from:

•  each other

•  the average for the group

• Difference in group averages between groups

Hints

•  To get different animals running try blowing, lightly pushing, turning off the lights, tapping the table… Anything short of pushing them the whole way.

In case things don't work out…

Some of our values:

•  Beetle- 

Times:

•  0.40m/15s

•  0.40m/6sec

•  0.40m/11sec

•  0.40m/5sec

•  Average body length: 0.017m

-----------------

•  Carpenter Ant-

Times:

•  0.30m/5sec

•  0.22m/6sec

•  Average Body Length: 0.010m

----------

•  Cockroach

Times:

•  0.40m/1.2sec

•  Average Body Length: 0.04m

------------

•  Spider (funnel web)

Times:

•  0.40m/3sec

•  Average Body Length: 0.01m