Science as a Why is the sky blue

Science as a

Why is the sky blue? Have you ever wondered why the sky is blue? One of the first science questions that was asked was why is the sky blue? They first made an observation: The sky is blue. They then asked the question: Why is the sky blue?

What’s Next • Come up with a hypothesis with your neighbor for the question: why is the sky blue? • Remember: A hypothesis means a testable statement. • The hypothesis should be in the form of a statement, (sentence) and the sentence needs to have the ability of being tested

So… Why is the sky blue?

• By: D. Gioffre, Hillsborough Middle School, Hillsborough, NJ 08844 • www. engineeringplanet. rutgers. edu • Pictures from: – http: //teacherweb. com/CT/Madison. Middle. School, Trumbull/Mr. Curry/links 1. aspx

What is Scientific Method? Process which outlines a series of steps used to answer questions.

What are the steps? 1. OBSERVATION: Process of gathering information about events or processes. 2. HYPOTHESIS: An educated guess made to answer questions or problems. 3. EXPERIMENT: conducting a carefully controlled search for truth about a hypothesis. 4. CONCLUSION: Analyze results to see if the hypothesis is correct. If not, start over.

designing the

What is Experimental Design? Includes two groups: Control and Experimental.

control group Group where all factors are held constant. This is needed for comparison!

experimental group Group you are testing where only one factor is changed. There are three variables within the experimental group: Dependent, Independent, and Controlled.

dependent variable The result. It’s what happened. What you measure. The response. The ‘’then” part of a hypothesis.

independent variable The factor you purposely change/manipulate. It’s the thing you are testing. The ‘’if” part of a hypothesis.

controlled variables / constants all factors which are NOT allowed to change during the experiment

repeated trials Experiments must be repeated several times using exactly the same conditions to see if the results are consistent. The more times you repeat the experiment, the more VALID your results are.

-axis anipulated ndependent MIX ependent esponding/ Result DRY

Theory vs. Hypothesis Theory- A well tested explanation that brings together many observations. It’s not a law and not absolute truth! Supported by lots of experimenting by lots of scientists. Hypothesis- A proposed scientific explanation for a set of observations.

Inference vs. Observation Inference- making a decision based on what you already know. Ex: We can’t test all the water, but we test a little and know it’s safe. We infer that all the water is safe to drink. Observation- gathering information about things in a careful, orderly way. We use our sight and hearing a lot when making observations.

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N E E P X R E M I 6 4 2 fe A T L dr o ps dr o no U G rt ili O R ps ze r rt ili fe fe fe TR rt O ilize L r N CO P ze r What group is this?

What are these called? S T N A T S N O C

What variable is this? e l the results (of adding fertilizer) b a i the response (to adding fertilizer) r a the effects (of adding fertilizer) v t n e d n e p e d The plant growth that you observe here can be called. . . 0 2 4 6

What do you do if you want to test the type of soil instead of fertilizer? iv type of soil fertilizer constants amt. of water dv plant growth fertilizer type of soil amt. of soil type of plant Fertilizer becomes a constant. Type of soil becomes the IV. type of planter size of planter type of light location

Evaluate the experimental design in the next two slides.

Dirt: The New Muscle Juice • • Eight year old Play with trucks 2 months Give water • • Eighteen year old Weight lifting 6 months Give Dirt Which kid will be stronger? Good experiment?

Questions • What are the controlled variables? • What is the independent variable? • What would be the dependent variable?

forming a

iv dv constants fertilizer amt. of water plant growth type of planter ve b r ve type of plant + + amt. of soil rb type of soil size of planter type of light location If fertilizer is added to plants, then plant growth will improve.

Take 7 minutes to design an experiment using the IVCDV chart to test the strengths of various sunscreen on aliens. 5 spf 10 spf 15 spf 20 spf