Observing
Bulbs
Part II: The Mystery Inside
Overview:
If you've done Part 1
of this lesson, you've carefully observed the outsides of the tools
you'll use to gauge spring's arrival. What more can you discover by
looking inside these precious packages? |
What
do you suppose we would find if we looked inside a tulip bulb?
Teacher
Background: A
bulb is an amazing container: a swollen underground stem that
stores food energy and contains a miniature plant with flower,
leaf, and root parts, all ready to spring forth when conditions
are right. But don't reveal this to your students just yet;
let them first make their own discoveries! |
Laying
the Groundwork
Ask, What will we find inside a
tulip bulb? Accept all ideas and ask students to explain their
thinking. Finally, invite the class to take a trip inside and see
for themselves.
Exploration
- Dissect
bulbs. Give each group of 4 to 6 students a magnifying
lens and a bulb. (Make sure these are extra bulbs and not
the ones students will plant.) Slice each bulb in half lengthwise,
from the pointed top down through the base of the bulb. If you
have enough, also slice one horizontally for comparison or ask
students how they want you to slice it.
- Draw
and reflect. Pass
out copies of the journal page, My
Tulip Bulb: An Inside Peek. Tell the class that this may be
their only chance to look inside a tulip bulb, so they should
try to draw every detail they notice. Explain that each part of
a living thing serves a role in survival.
As students focus on specific parts of the bulb, have them think
about the "why" (Why is this here?) and the "what"
(What could it be?) behind each part they see. What
new observations and ideas do they have when they look through
the magnifying glass?
- Share
ideas.
As a class, discuss the different parts of the bulb students observed.
Make a class chart like the one here (to the right).
- Compare
ideas with what scientists say.
Finally, explain that a tulip bulb contains all that's needed
for a tulip plant to burst forth, grow, and flower when conditions
are right in the spring. Give each small group a copy of the Parts
of the Tulip diagram. Have them try to find the labeled parts
on their own bulbs if they haven't already. Compare what they
learn with the ideas on the class chart. What new questions do
they have?
|
|
WHAT
we saw |
WHY
we think it's there |
WHAT
it could be |
Things
that look like rings of an onion |
To
protect the tiny plant we think we see? |
Not
sure; leaves? |
|
|
|
Use
a class chart to share your ideas
|
Discussion
and Journaling Questions
- Now
that you've explored bulbs, inside and out, why do you think we're using
them to track the greening of spring?
- How
do you think different bulb parts will change in the spring? What do
you think will cause them to change?
- Do
you think the weight or size of a bulb will affect when or how it comes
up and blooms in the spring? How? (Consider doing the Digging Deeper
activity, below.)
Digging
Deeper:
Using Bulb Observations to Make Predictions
Now that students understand that tulip bulbs will, in fact,
grow into new plants, consider conducting this activity. Do this
before you put the bulbs in the ground. It engages students in
making predictions about how the size or weight of bulbs (explored in
Part 1) might affect their growth in the spring.
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