Evidence vs. Inference
Write at least the statements in green
Ancient Greek
philosophers started
the scientific tradition
of logical thinking, but
they sometimes
missed out on an
important aspect –
gathering evidence.
Many philosophers developed their claims
through contemplation and thought rather than
experimental procedure, which sometimes led
to errors.
Aristotle contemplated these facts:
*Males are larger than females, and
have more room in their mouths
*Males fight more than females, and
sometimes use teeth to fight
*Males eat more than females, and teeth
are required to eat
Aristotle made this claim:
“In mammals, males have more teeth
than females.”
If he had conducted
a scientific survey,
he would have found
that males and
females have the
same number of
teeth.
Our claims must always be based on evidence,
not just logical ideas.
• Evidence is what you know for sure. Evidence
comes from direct observations, measurements,
or experimental data.
Two types of data come from observations:
Qualitative Data characteristics that you
can observe with your
senses (color, texture,
taste, odor, etc)
Quantitative Data numbers obtained by
counting or measuring
(height, mass,
temperature, etc.)
• Inference is what you
assume or guess based
on the evidence and
based on your own
experiences.
Let’s practice gathering evidence
and making inferences.
Where is this kid and what is he doing?
What is the temperature?
Evidence:
Inference:
What is the occasion?
Evidence:
Inference:
What happened?
Evidence:
Inference:
Inference vs. evidence
• What is the evidence here?
• What inferences might you make?
Inference vs. evidence
• What is the evidence here?
• What inferences might you make?
Inference vs. evidence
• What is the evidence here?
• What inferences might you make?
Some scientists investigate things that they cannot
observe directly. For example, scientists cannot
see living dinosaurs. Scientists want to know more
about dinosaurs, so they gather evidence
about them in other ways.
One way that scientists find out more about
dinosaurs is by making observations of coprolites,
fossilized dinosaur droppings.
When scientists figure out what is in the dinosaur
poop, they can then make inferences about what
the dinosaur ate when it was alive.
They are not observing the dinosaur eating—they
are using evidence to make an inference.
Over time, scientists gather more evidence that
helps them know whether or not their inferences
were correct.
Let’s examine some multiple pieces of evidence,
make inferences, and put multiple inferences
together to make a claim.
We had some neighbors
move in last week, and I
want to know more about
them before I deliver a
house warming gift. I stole
some of their trash…
I found …
Evidence:
Inference:
I found…
Evidence:
Inference:
I found…
Evidence:
Inference:
I found a poster…
Evidence:
Inference:
I found…
Evidence:
Inference:
I found…
Evidence:
Inference:
How many children are in the family?
What are their approximate ages?
Big Ideas:
1- All science knowledge is
based on evidence.
2- When we get new
evidence that is different
from before, we change
our ideas to include the
new evidence, but we still
keep the old evidence.
3- Science knowledge is
always changing.