1. Scientific Method and CER

2. Observation: objective; based on the 5 senses, not opinion.
Science: a method for studying the natural world by gaining knowledge through observations and investigations.
Scientists gather information through observations and design investigations based on inferences.
Observation: objective; based on the 5 senses, not opinion.
Ex. The ground is wet.
Inference: subjective; a guess about an observation based on evidence.
Ex. It rained. Someone spilled something.

3. Steps of the Scientific Method
Identify a problem
Gather information
Formulate a hypothesis
Design and experiment
Record and organize data
Analyze data
Draw conclusions

4. Step 1: Identify a problem
Observe the world around you
Using observations, identify a problem you would like to solve
Example: Do fish that are kept in a tank grow as large as fish in the wild?
This is a question you DO NOT know the answer to and can’t look up.
“Why” and “What would happen if..” are good beginnings of scientific questions.

5. Uses our senses to gather information Qualitative: uses our 5 senses
Observation
Inference
Uses our senses to gather information
Qualitative: uses our 5 senses
Ex. Fish that live in a 5 gallon tank do not grow as large as fish kept in a pond.
Quantitative: uses numbers
Ex. Fish kept in a 5 gallon tank are 2 centimeters long. Fish in the pond are 10 centimeters long.
A logical interpretation of events based on prior knowledge or opinion
Educated guess
Ex. Fish that are kept in tanks have less room to swim and get stronger so they grow less.

6. Step 2: Gather Information
Use references to do background research
Books
Journals
Magazines
Internet TV
Videos
Interview Experts
Example: Fish
Live in ponds and streams
Are naturally found in bodies of water larger than fish tanks.

7. Step 3: Formulate an hypothesis
Hypothesis: a testable prediction that attempts to answer a question.
Usually predicts a cause and effect relationship between variables.
“If” “Then” “Because” statement
Fish:
If fish are kept in a tank less than 5 gallons then they will grow less than fish in the wild because they have less room to develop muscle mass.

8. Step 4: Develop an experiment
Materials
A list of all the things you need to conduct your experiment
Tank
Fish
Food
Etc.
Procedure
Step by step instructions
Identifies the variables used in the experiment

9. Variables: Independent & Dependent
The variable that can be changed or manipulated
After “If”
Example:
The size of the fish tank
Is measured in the experiment
Changes because of the independent variable
After “then”
Example:
Growth of the fish

10. Variable: Constant
All the factors in the experiments that are kept the same
Everything except the independent variable
Keeps the experiment ‘fair’
The amount of food given to fish
The temperature of the water
The chemicals added to the water
The types of things in the tank with the fish
Ages of the fish used in the experiment

11. Variable: Control
A control group in a scientific experiment is a group separated from the rest of the experiment. This group is not being experimented on.
Example:
The fish that are in their natural environment (pond)

12. Step 5: Record and Organize Data
Write all observations and measurements
Use a table to organize your data
List your independent variable on the left side
Record your dependent variables on the right side
If you have more than one dependent variable, use a new column for each dependent variable
Independent (tank)
Dependent (size)
5 gallon tank
2 cm
10 gallon tank
4 cm

13. Step 6: Analyze Data
A picture is worth a thousand words, they say. A graph? Maybe more.
Scientists use graphs to show relationships and model trends. The type of data dictates which graph would be most useful. Here are a few examples:

14. Graph Types

15. Graph Types

17. Step 7: Draw Conclusions
Good conclusions are based on validity from repetition
Conclusion should include:
A clear statement of if the data supports the hypothesis or not.
Never say “proven,” “disproven,” ”correct,” or “incorrect”!!
CER model

18. What is a Scientific Explanation?
Claim Evidence Reasoning

19. The claim-evidence-reasoning model provides you with an objective, scientific structure to support you in developing a conclusion.

21. I have evidence that proves my Dad’s a space alien.
He speaks a weird language.
He drinks green stuff.
He says he’s from Albuquerque (I’m not buying it).
I mean, just look at him.
And one more thing. He has a space ship.
The evidence doesn’t lie.
My dad’s an alien.

22. Question:
What do you want to know?
Claim:
• A statement that answers your question (one sentence)
Evidence for your claim:
• Scientific data that support the claim
• Data need to be appropriate
• Data need to be sufficient (more data = strength!)
Reasoning (how your evidence justifies your claim):
• Based on scientific principles
• Each piece of evidence may have a different justification for why it supports the claim
• Usually several sentences; useful prompts include “if, then”, “therefore”, “because”, “since”

24. Question: …
Question:
Claim:
Evidence:
Reasoning: … …

25. The evidence doesn’t lie...
Question: Who is my Dad?
Question:
Claim:
My Dad’s a space alien
Evidence:
He speaks a weird language
He’s from Albuquerque
He drinks green liquids
He dresses funny
He drives a spaceship
Reasoning:
The evidence doesn’t lie...

26. Question: Who is my Dad?
Question:
Claim:
My Dad’s a space alien
Evidence:
Reasoning:
He speaks a weird language
He’s from Albuquerque
He drinks green liquids
He dresses funny
He drives a spaceship
Aliens are not from Earth so they have their own language
Some people believe that aliens have landed in NM
Which is why many aliens are seen with green skin
Aliens wear space suits for protection
Aliens use spaceships to travel

27. Science and Engineering Practices
Asking questions and defining problems
Developing and using models
Planning and carrying out investigations
Analyzing and interpreting data
Using mathematical and computational thinking
Constructing explanations and designing solutions
Engaging in argument from evidence
Obtaining, evaluating, and communicating information

28. Practices relevant to C-E-R
Asking questions and defining problems
Developing and using models
Planning and carrying out investigations
Analyzing and interpreting data
Using mathematical and computational thinking
Constructing explanations and designing solutions
Engaging in argument from evidence
Obtaining, evaluating, and communicating information

29. Practices relevant to C-E-R
Asking questions and defining problems
Developing and using models
Planning and carrying out investigations
Analyzing and interpreting data
Using mathematical and computational thinking
Constructing explanations and designing solutions
Engaging in argument from evidence
Obtaining, evaluating, and communicating information

30. Lets Practice!
Problem: Does the size of the pot a plant is grown in affect how tall the plant will grow?
Hypothesis: If the plant pot is larger, then the plant will grow taller, because the roots have more room to spread out.
Observations: After 31 days the following plant heights were recorded.

31. Claim:
Evidence:
Reasoning:

32. Claim: With a larger pot, the plants growing will grow taller.
Evidence: The bean plant in the pot with a 5 cm diameter grew 15 cm tall and the bean plant in the pot with a 25 cm diameter grew 39 cm.
As the pot size increased from 5 cm to 25cm in diameter, the bean plant height increased from 15 cm to 39 cm.
Reasoning: Because the bean plant height increased as the pot diameter increased, it proves that the larger diameter pot will grow a taller plant. Plants roots need space to spread out to maintain the height of the plant and collect the nutrient the plant needs. There is also more soil in the larger pot, so there are more nutrients.