My book "Plant Biology Science Projects" has a few exercises that can be
done in one period:
- starch testing of leaves
- leaf disk measurement of photosynthesis
- use fingernail polish to make impressions of stomata and examine
them under a microscope and count density of stomata
- measure transpiration of potted plants with a balance under high
and low transpiration environments
- measure carbon dioxide production and oxygen consumption of
germinating seeds
- calculate costs of various houseplant fertilizers (mostly math
application)
Other possibilities:
- study transpiration by dying carnation flowers (need to wilt
flowers ahead of time so dye taken up rapidly)
- determine what makes Venus flytrap traps close (repeat Darwin's
experiment)
- examine dispersal of winged seeds (Jan. 99 Amer. Biology Teacher)
- cook and eat unusual plants or wild plants
- extract chlorophyll and make a chlorophyll absorption spectrum
using a spectrophotometer
- students set up a mini-terrarium and take it home to observe
- key out unknown plants using a field guide
Many exercises can be done in one period if the teacher sets up the
experiment in advance and just has the students take the final data.
This is the cooking show strategy because on cooking shows they mix up
the recipe, pop it in the oven, and then immediately open another oven
containing the fully cooked dish.
- deficiency symptoms of hydroponic plants (students record plant
size and symptoms)
- count roots on cuttings treated with and without rooting hormone
- record germination percentages of seeds treated in various ways
such as scarification or stratification, different light colors for
lettuce seed
- cut flower vase life as affected by various treatments such as
aspirin, sugar, flower preservatives, etc.
You really do limit yourself if you only do labs that can be done start
to finish in one period. Students often become more fascinated with
plants by observing them daily or several times a week so they see them
grow. For example,
- forcing an amaryllis or other flowering bulb in the classroom
- growing plants hydroponically to observe root growth and deficiency
symptoms
- growing Wisconsin Fast plants, hand-pollinating them, and watching
seed develop
- germinating seeds
- root cuttings with rooting hormones
- photoperiodism effects on flowering
- carbon dioxide deficiency
- grow ChiaPet or grasshead
- growth regulator effects on plant growth
- plant tissue culture
- acid rain effects
- seismomorphogenesis (shaking effect on growth)
- vegetative reproduction - give each student a foliar plantlet from
Devil's Backbone (Kalanchoe daigremonitiana) and have contest to see
which student can grow the most plantlets by the end of the school year.
David Hershey
dh321 at excite.com
QDurham wrote:
>> I'd sure be interested in hearing about short (one class period ideally)
> hands-on exercises/experiments for middle grade kids. These sorts of
> activities are easily accomplished in physical sciences, but are tough to do in
> Botany/Biology
>> Quent
