"Jude" > wrote in message
oups.com...
..
>
>
> Ummm, the child is 9. I thought it was pretty good that she was able to
> identify that yeast is another ingredient used to leaven breads.

Well, there are many ways to leaven thing including steam. You ignored my
points. First you are mixing various types of leavening agents - chemical
and biological. Second, you are not making a meaningful comparison since
you aren't letting the yeast work. Exactly what does the experiment prove
other than that not allowing the yeast to ferment is not an valid way to
leaven baked goods? It doesn't compare the leavening ability of yeast vs.
baking powder. It just illustrates that not following directions is a
recipe for failure.

The
> only variable is that she is changing the leavening agent.

Except that baking SODA is not a leaving agent. It is PART of a system that
requires an acid. Baking POWDER is a complete system and is a leavening
agent. Also, all leavening agents only work in a specified range of
temperature and over a specified time. By not giving sufficient time for
the yeast to ferment you have designed a flaw in the protocol. Again, it
makes no sense to say that a particular agent is inferior when you design a
system that guarantees failure.


She will
> substitute 2 t of yeast for the 1 t each of soda and powder in the
> original recipe. She will see why it doesn't work, and she will learn
> that yeast leavens differently that soda or powder.

No, she will see that it doesn't work but there is no clear reason WHY it
doesn't work because you haven't design the experiment to include TIME as a
variable. The only conclusion one could make was that yeast isn't a
leavening agent. In fact, one could argue that the yeast might be dead
since you have no control to prove otherwise. Again, this starts to get way
too complex for a 9 year old so why clutter the system with meaningless
comparisons? A more fair comparison would be to add the yeast to one batch
and the baking powder to another and bake-off a portion a set intervals.
Given enough samples over a long enough period of time you would see that
the leavening properties of baking power diminishes and the leavening power
of the yeast increases with time.

There really is no
> other variable in effect here.

See above. You are obviously wrong.


Her science teachers agreed that this
> was an entirely appropriate experiment for a 4th grade.

And of course, a 4th. grade teach is the ultimate authority on science.
That's why all the very brightest students can be found majoring in
education leaving the slackers to study physics, mathematics, chemistry,
engineering, medicine, etc. Oh, wait, it was just the opposite when I
attended college.

This is not a
> college-level organic chem class.

This would be an experiment for inorganic chemistry. When you mix in the
yeast, you would have to take it to biochemistry.

Its the elementary school sciecne
> fair, and a kid whose mom cooks and bakes, thus a fun project to try,>
> emulating Mom.

Oh, sorry. I thought this was about science, not emulating mom. I also
didn't realize that having fun and being logical were incompatible concepts.


> Again, this is a fourth grade. It is not MY assumption, it is HER
> hypothesis. A hypothesis for a science fair project is simply a theory
> to be tested. How many fourth graders have a deep knowledge of how CO2
> is produced by chemical leavening agents?

Sorry, when you said that she researched how CO2 was produced, I took your
word for it. Maybe you meant something else?

My knowedge has zip, zilc,
> zero to do with this. Amazingly enough, I'm a mom who is actually
> making HER do her own science fair project and see what she can learn.
> My knowledge does not come into play here. The purpose of the science
> fair is for a child to deisgn an experiment and then to perform it.
> They analyze the results and gain new knowledge based on what happens.
> The purpose of her experiment os so she CAN learn more about how
> leavening agents work. Not to mention that since the original recipe
> calls for a combo or soda and powder, it's probably a good hypothesis.

First, you didn't post the original recipe. Secondly, I find it
inconsistent to first argue that the girl is young and naive and then to
insist that she will be able to learn anything from a muddled experiment. I
have suggested a couple of ways to simplify the experiment so one can draw
clear conclusions that are explainable. And, while you claim that the girl
is on her own, she is using YOUR recipe - one that uses two potential
leavening agents, thus mudding the waters. I agree that the experiment is
your daughter's, I think that as a parent you could ask questions and be
part of a discussion that could guide your daughter. I guess that some
people see parenting as a hands-off endeavor.
>
> I disagree that it would be more educational to bake only variations on
> the bread and never follow the original recipe we are using.

The "original recipe" is the first in a chain of errors. Unless your
daughter found this recipe herself, you have interjected yourself into the
process and therefore can not claim an "arm's length" relationship.

What would
> she learn from that? The purpose of comparison is to have 1 loaf that
> comes out exactly as it should, following the recipe to a T, and then
> vary the recipe to see what happens. Without 1 loaf made exactly as
> directed, we have no 'control' to compare to.

At this point it is impossible to tell. That is my point. In addition, we
have no idea if the baking soda in the "original recipe" is included as a
leavening agent or as a way to increase browning, enhance gluten formation,
or to modify the flavor. You have made the assumption that baking soda is
always a leavening agent- but it isn't. See, the recipe is inappropriate to
test your daughter's hypothesis.

>
> You do realize that most 4th grade science fair experiments consist of
> putting food coloring into a vase with a carnatin and seeing the flower
> absorb the color? This one she came up with is perfectly appropriate
> for a little kid.

Your premise about the flowers doesn't support your argument about
appropriateness of your daughter's project. You also ignored all my points
that explained why the experiment isn't appropriate because it introduces
too many concepts and leads to no clear conclusions.


perhaps a high school students with many more years
> of sceintific experimentation would be interested in the advanced ideas
> you propose, but not a little kid.


That's the point. Unless you streamline the experiment, it would take an
older student to design and execute the experiment, analyze the data, and
compose a logical discussion of the data.