Scientific Explanations/Arguments Claim-Evidence-Reasoning (Justification)

Scientific Explanations/Arguments Question - Guiding Question Claim - A one-sentence statement that directly answers the question you investigated It answers, what did you conclude? Does NOT start with yes or no. Evidence - Scientific data used to support the claim Provide sufficient data (more data = strength) Use appropriate data (use data that supports your claim and leave out information that doesn’t support it) Use qualitative and quantitative properties of matter Reasoning/Justification of the Evidence - Ties together the claim and evidence Includes scientific principles that are important to the claim and evidence Shows how or why the data count as evidence to support the claim Provides the justification for why this evidence is important to this claim

Claim Sentence Starters: I observed _____________ when ___________. I compared _____________ and ___________. I noticed _______, when _______. The effect of _________ on ___________ is ___________ As _____________ increased/decreased, _____________ increased/decreased/stayed the same.

Evidence What to include: Analysis - show a trend, difference, change over time, or relationship Use tables, graphs, figures, descriptive observations (qualitative), and/or numeric values (quantitative) Interpretation - explain what the analysis means The graph/table/etc indicates… This graph/table/etc shows… This graph suggests... Sentence Starters: In the data … The evidence used to support _________ is __________. I believe _______ (statement) because _________ (justification). I know that __________ is _________because ________. Based on ____________ , I think ____________ . Based upon ____________ , my hypothesis is ________ .

Reasoning/Justification of Evidence What to include: General scientific principles Background/ prior knowledge Sentence Starters: Based on the evidence, one must conclude… because….. The most logical conclusion that can be drawn from this evidence is that…. because…. These facts work together to build a case that… because… All of this proves that….. because… The reason to believe __________ is because _______.

Physics Example What type of pulley system requires the least force to move the block? A pulley system with two moveable pulleys and one fixed pulley required the least amount of force to move the block. (Claim) The system took an average of 0.82 Newtons of force to move the block. We tried three other systems, but the closest one was still 0.23 Newtons more, because it required 1.05 Newtons. (Evidence) The fixed pulleys just change the direction of the force, while moveable pulleys reduce the amount of force. Using one fixed let us have two moveable pulleys, which decreased the force more than just having one moveable pulley. (Reasoning)

Biology Example What will happen to the shark population if the phytoplankton populations die out? The shark population will die out. (Claim) The shark eats other fish such as the ocean fish and the lantern fish. The ocean fish and the lantern fish eat other organisms such as shrimp and copepods. The shrimp and copepods eat the phytoplankton. (Evidence) All of the other organisms in the food web depend on the phytoplankton, even if they do not directly eat them. Organisms are affected by other organisms in a food web even if they are not directly linked to them. (Reasoning) You might think the shark population would not change, because they do not eat the phytoplankton. But they will actually die out because they eat organisms that eat the organisms that eat the phytoplankton. (Rebuttal)

Example 1 - “My Dad is an Alien” Guiding Question: Is the little girl’s dad an alien? After watching this video clip your group will do a Claim-Evidence-Reasoning scientific explanation on big whiteboards.

Example #1 - “My Dad is an Alien” Guiding Question: Is the little girl’s dad an alien? Claim: Her dad is an alien Evidence: Speaks weird language Has a spaceship; drives a spaceship From a place with a weird name (Albuquerque) Drinks green stuff Looks or dresses funny Reasoning: The girl’s dad is an alien. Aliens are not from Earth so they have their own language or way of communicating. He’s from a place that has a weird name (like different planets or outer space objects). Aliens wear space suits for protection. Aliens use spaceships for travel and he has a car that is very high tech. They walk funny. They drink food that humans can eat (green stuff). Therefore, her dad is an alien.

Example 2 - “Prom Punch” Guiding Question: Did the boy get punched in the face at prom? After watching this video clip your group will do a Claim-Evidence-Reasoning scientific explanation on big whiteboards.

Example #2 - “Prom Punch” Guiding Question: Did the boy get punched in the face at prom? Claim: The boy was punched in the face at prom Evidence: Black eye Kissed another guy’s girlfriend Prom King yelled and walked up to him really mad Reasoning: The boy was punched in the face at prom. When you get hit hard in the face, it bruises because blood vessels break (called a black eye). When someone kisses someone else’s girlfriend, they get mad. When some is mad enough, they may approach you angrily. The boy kissed the Prom King’s girlfriend and the prom king got really mad. The boy had a black eye on the way home. Therefore, the boy was punched in the face at prom.

Example 3 - “Plants in Light” Guiding Question: “Do plants grow better in sunlight?” Sammy wants to see if plants really do grow better in sunlight. He uses 3 plants of the same type and size in 3 locations. Plant A is placed on the table in the center of the room, Plant B is placed inside the cabinet, and Plant C was placed near a window sill. After 5 days Sammy measures the growth of each plant and documents it in the table below.

Example #3 - “Plants in Light” Guiding Question: Do plants grow better in sunlight? Claim: Evidence: Reasoning: