Concept 2 – Cause and Effect

Hi. It’s Paul Andersen and this
Crosscutting Concept 2. It’s cause and effect. Cause and effect is innate in humans. In other
words from a young age we want to know why something occurs. In other words, what causes
the ripples on the pond? We want to know that mechanism. We want to explain why it occurs.
And so it’s innate in us but it’s something that we also want to develop in a science
classroom. Because in science, cause and effect allows us to explain causal relationships.
This effects that. And in engineering it’s a little bit different. We want to be in control
of the cause so we can also control the effect. Especially in a design. And so when you’re
presented with a question, cause and effect comes right away. And so let me give you a
good question. This is a rattleback. A rattleback is a piece of plastic that has a unique behavior.
And so in this video what I’m going to do is I’m going to spin the rattleback and it
will spin. I’m then going to try and spin it in the opposite direction and it will rattle
and then it will come back again. Let me try that again. So I’m going to spin it like this.
It’s going to rattle. And then it’s going to spin back. And it wants to spin that way
so much that if you just touch it, it’ll start to spin in that direction. Okay. Now I’ve
given you a good question. And so what you should be thinking is what’s causing that
rattleback to have that behavior? In other words is it a magnet that’s in here? Is it
somehow asymmetrical? Is it somehow . . . a weight inside of it? And so, our mind jumps
to this idea of cause and effect. But one thing that we want to make sure that students
understand is that if we’re saying A causes B, then we have to have a chain of interactions
from A to B. In other words we want to link A to B. We really want to make sure that A
is causing B. And sometimes that’s super simple. So if you see a home run, in other words a
baseball go over a fence, you know the cause of that home run. It’s the bat that hit the
ball, because you can physically see it. And so now you have a nice chain of interactions.
Since we can see that and we can video that bat impacting on the ball, we can say that
A is actually causing B. But sometimes it’s unclear. And so for a long history of humanity
we didn’t know what causes disease. We didn’t know what causes chicken pox for example.
A lot of people thought it was just bad air. And if you would have said to somebody that
there’s something on your hands that’s causing that disease and so you need to wash your
hands, people back them would have been skeptical. And the reason they would have been skeptical
is that there’s no chain of interaction. There’s not anything that we can see that’s linking
the washing of your hands to a decrease in those infectious diseases. And until we had
studies where we could actually prove that or we could see the virus, we could see the
bacteria, we really couldn’t say that A causes B. And sometimes those causes are really complex.
And so if we were to look at an ecosystem for example or if we were to look at climate.
Global warming is a great example of that. We know that the climate is getting warmer.
So we can see that in the record. But we don’t know specifically all the causes of the that.
We know that carbon dioxide is one of the big ones. Greenhouse gas is one of the big
ones. But there’s so many variables at play, it’s hard to tell what are all of the causes.
And also sometimes it’s just a probability. So if you’re looking at a particle, what’s
the probability that we’re going to get radioactive decay? What’s the odds of that? Well you can
predict. You have a probability of how often that’s going to occur in a specific period
of time. But we can’t say it’s going to happen right now. And here’s the cause and here’s
going to be the effect. And so one thing that we want to make sure when we’re talking at
this root level of cause and effect, this idea of universality. And it’s an assumption
that we make. In other words, in the universe there are four basic forces. And those forces
are gravity, electromagnetism and then the strong and the weak nuclear forces. And so
basically we’re going to assume that the universe is that same here as it is everywhere. We’re
going to assume universality, that these forces are the same everywhere. And that’s actually
a pretty big assumption. One other thing that we want to make sure that were talking about
is the scale. And so if we’re looking at something at a large scale, like climate or let’s get
a little smaller, let’s say the structure of this protein right here, well that’s definitely
determined by all of the atoms that are found within that protein. But even though we understand
all of these interactions at the small scale that doesn’t mean we can predict what’s going
to happen at the large scale. Even though what happens at the large scale can’t violate
those rules at the small scale. And so what’s the goal in a science classroom? We want to
make sure that our students are starting to see causation. Or link causation, cause and
effect. Example, we would want them to see patterns right away in the early elementary
grades and then we want to explain the unexpected. And so when you see that rattleback spin,
that’s a great example of something that you would want to present your students with,
so they can come up with a lot of different causes that we can then test. We then want
to move on to argumentation. So as we move into middle school and high school, not only
do we want them to put forward a cause but we want to argue for that and give evidence
for that. And so examples could be let’s apply theories to things that we are seeing. Let’s
apply laws that we have, laws of nature, to observations that we make. And then we want
to do that observed phenomena. So actually seeing what’s occurring and then trying to
explain all of the causes that make it occur and then try to make argumentation from that.
And so where would this occur at the early elementary grades? We want to basically start
sensing patterns and we to take those patterns and then try to link those to a cause. So
a great example could be plant growth. And so you could have kids growing plants and
then we could see what’s effecting that. So water is clearly going to effect plant growth
they might say. Light is going to effect plant growth. But you want to come up with as many
different causes as you can. You want them listing those causes out. And then as we move
into older grades, especially in elementary, we want to present them with weird observations.
In other words we want to present them with discrepant events. And so a great example
of one could be the moon. And so the moon is going to go through phases, so a good question
is if the moon looks like this, how are the moon and the earth organized so that you can
get something like that? And it’s a great thing you can do in the classroom where you
take a model of the moon. You have a light source and you can kind of figure out where
do I have to hold the moon if I’m the earth to get a shape that looks like it? As we move
into middle school and high school, we want to start using argumentation. In other words
we want to go to theories, establish theories to explain phenomena. And so why a lever works,
we could go over that in a classroom, but then we could present them with phenomena.
And then they’re going to try to explain that. So that’s a great one that I’ve done in class,
where you put, once they learn that the load and the distance from the fulcrum is related,
you can give them a load on one side and predict how far a load has to be on the other side
so that you can get it to balance. And then we want to give them harder problems as they
move through high school. So this is a dead zone for example. It’s in the Gulf of Mexico.
And every year we have this area in the ocean where everything dies. And that’s because
of decreased oxygen levels. And so you want them to come up with as many different causes
as there possibly could be. You want to list all of those and so then we could start doing
some research or we can start doing some testing to see which of those causes are correct.
So cause and effect is innate in us. It’s really cool and so are rattlebacks. And I
hope that was helpful.

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