
Core ideas and cross-cutting concepts. The framework and the NGSS define big ideas
that have explanatory power for making
connections among ideas
We want to think about questions. 
Instead of memorizing facts, formulas, and procedures,
the NGSS emphasize the usefulness of
ideas in explaining phenomena and
especially in making sense an unfamiliar phenomena.
This is water, because you can see some water right here.  
these fewer big ideas in each
discipline focus on a deepening of
knowledge to allow students to make
connections among ideas and across
disciplines to mirror the way scientists
approach the world. 
For example, a scientist could look at a rain event with
the lens of patterns. Is it similar to
other rain events? Or systems--where are the
inputs and outputs of the flow? Or cause
and effect--how will the water affect the
soil in this area? These are lenses that
the teacher must make explicit for
students who are learning to acquire the
unique way that scientists approach
phenomena.
That's the best way to make them aware is to see that 'oh, someone may have just
said something that is going to really
help us understand.' 
How does a teacher,
such as Melina, approach science, so
that students can think about patterns
and cause and effect, to discuss
interactions between the Earth systems
in an authentic way?
So they start out the day after a rain and the students are
just thinking about 'what is the evidence?'
So scientists use evidence when they may
claims, and this is kind of a new thing for a lot of kids to think, 'I can say something,
but it has to have evidence to back it.'
What about footprints? We didn't see many
of those yesterday.
I think it rained, because wet footprints.
Because the wet footprints, very nice.  
The first day the students
show that they have a lot to build on.
That they have a lot of ideas about what
counts is evidence, and how you can
determine if something is evidence of
snow and rain.
We start with questions,
simple questions, like 'do we know that it
snowed last night?' 
What would the
evidence be for that then. Yeah. 
There's snow on the floor.
That we would have seen snow
on the ground or not. 
On the trees.  
And on the trees. 
There was snow on the ground. Anything else? Yeah
Probably snowed in the morning. And
what would your evidence for that be?
Could have snowed a lot.
Because there might have been a lot of snow on the ground. 
I'm going to say a lot. How's that?
Good. So then this would be our
evidence. What we observed that made us
think that 'yes, indeed, it snowed. 
The students do not mention the cross-cutting
concept in their idea. Melina will want
to prompt them to start thinking about
using language that cues the lens of
cause and effect, patterns, and systems,
the cross-cutting concepts in the
performance expectations.  
The grass was wet, because I think it was raining.
Muddy puddles, muddy puddles, maybe it rained.
Melina supports the students
through her prompts, cues, and questioning.
Right, so it dried and then now
again in the morning, it's wet and not
only are the leaves and the trees and the
grass wet, but [her] shoes were wet,
and where they went yesterday afternoon,
let's say? Afternoon? 
No! 
Students start
with ideas than mud is evidence of rain
because it is still wet.
Many of them either focus on the
evidence of actual water, or the evidence
of soil mixed with water.
Next, the students talk about other kinds
of evidence like a river that water can
carve into the Earth over time.
Is that mud over here? 
No!
What is that?
Water.
It's what? Can you say that really loud? 
Chips.
Chips of what?
Wood!
Melina uses a sorting
activity and a discussion for men to
build the idea that you can find
evidence of rainwater by observing the
track it made.
Maybe they were digging a line and then the water went, and it was like a river.
Maybe, someone, her or him, were driving their bicycle, and then they made a line in the dirt.
Ok, so we have water you can see. Which
ones belong in that category. 
That one.
This one.
What else? 
This one.
This one, ok. 
This one. 
And then these are the ones where you can't see
the water? 
I can kind of see the water. 
The core idea becomes more
sophisticated when the students observe
and discuss rapid changes to the land
with the help of a video of water and
debris flow in Yosemite.
The ice will surge into place and with enough
thickness it stops, and the creek
will flow a different direction.
The water will drain out of where it's just deposited it, leaving this what looks like snow. 
But you'll see
this lava flow effects, where the ice is
going to accumulate and build up
blockages that stop it from coming in a
certain direction.  
Notice that the students are using the cross-cutting concept of systems, or patterns, to help
them think about the core idea. 
So you see some evidence of water maybe from day before,
or the week before. 
And Melina's cues help them make the connection.
And this one, there's change because 
the water brought these things. And then it got dry, and the things were there, and the land changed.
Have you ever seen that before?
Yeah.  
You're sitting there looking, and what do you see?
Sometimes, there's some things that the water comes, and then it comes to this, and then it goes down
But it brings plants, sometimes, and they get stuck.
The big ideas can that students are working toward is that there are patterns that
can help you think about changes to the
land. Students are moving toward
developing more complex ideas and coming
up with rules that can guide future
thinking in Earth science. 
It takes time to incorporate cross-cutting concepts.
Melina has come so far and thousands of
other teachers are on the same journey.
Reflect and think about your own
experiences and share them below. 
How are you asking questions related to the cross-cutting concepts in your own
classroom

