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Describe a New Substance; EDC Insights
 Lesson
at a Glance:
Curriculum: EDC Insights, The Mysterious Powder, Kendall-Hunt Publishers
Grade: Upper elementary
Topic: Learning Experience 10: Using Science Skills to Describe a New
Substance
Prior to this lesson, Rebecca’s class had been working
for four weeks, investigating the different mystery powders, and trying
to identify them by observing their properties during various chemical
reactions.
In Rebecca’s adaptation of this lesson, the class took
two substances that they were familiar with, baking soda and vinegar,
and mixed them together. “They
knew that there was going to be a chemical reaction,” says Rebecca, “but
we took it a step further and put them into a closed container and weighed
them before and after they were mixed, to see if the matter would be
conserved.”
The first time the students did the experiment, they
put a balloon over the top of the bottle in which the reaction occurred,
so they could watch
the newly created gas fill the balloon. When the class weighed their
bottles afterwards, however, several students found that their bottles
weighed
less than they had before the reaction took place. Thinking that either
the balloons had small holes in them or that the seals were leaky,
Rebecca rethought the experiment and had the students replace the balloons
with
the bottle caps.
She recounts, “This time the students found
that the substances weighed the same before and after they were combined,
even though some of the matter
disappeared from view. And I think it’s important that students
realized that, sometimes in science when you do an experiment, it
doesn’t
always go the way you expect.”
After this lesson, Rebecca did
several follow-up lessons where the students investigated conservation
of matter through other chemical
reactions. “It’s
kind of a hard concept,” she said, “because if you watch
a piece of wood burn, it seems to be gone. So, the idea is to get
students
to understand that it’s not gone; it’s just changed its
form.”
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