1. Designing Experiments, part 2 September 3, 2015 (1.3 in your books)

2. Meme Moment clue

3. Scientist of the Day

4. Neil deGrasse Tyson Went to the Hayden Planetarium when he was 9 and suddenly wanted to be an astronomer Started lecturing on astronomy at 15 Carl Sagan invited him over Wrestling, rowing, and dance at Harvard Started running the same planetarium Took over Carl Sagan’s show

5. Controlled Experiments, part 2 A controlled experiment is one where only 1 variable is changed at a time This makes it easy to see cause & effect When you change 1 variable, you’re hoping to see a change in the result Independent variable: The variable you change on purpose Dependent variable: The change you see as a result of changing the independent variable

6. Vocabulary Manipulated variable: independent variable Responding variable: dependent variable Repeated trial: repeating the experiment several times to get better data through averages. Also called rigor. Replication: letting someone else repeat your experiment to check for biases 7 th and 8 th grade

7. Features of a Good Experiment 1.Free of bias o Personal o Cultural o Experimental 2.Controlled experiment o Test one variable at a time to see what actually changes the result 3.Repeated trials o Always better to do it more than once – that way you can take averages 4.Replication o Let other people repeat the experiment to see if they get the same result o Helps check for biases

9. Scientific Theories A scientific theory is very different from a normal theory. There are 3 ways to use a theory: 1.Normal person: just a guess. Sometimes silly. “Sam is late for class. He must have been abducted by aliens!” 2. Semi-scientific: sometimes people will use hypothesis and theory interchangeably. “My theory is that Diet Coke & Mentos is the biggest explosion.” (should have said “hypothesis” instead) 3. Scientific theory: An almost-indisputable explanation that’s constantly being tested. It’s a fact! “Germ theory states that some diseases are caused by microorganisms like bacteria.”

10. Scientific Theories You can call scientific theories facts. Germ theory Molecular theory Evolution Theory of relativity (E=mc 2 ) Gravity Plate tectonics Climate change

11. Scientific Laws vs. Theories Scientific law: Describes patterns that you always see in nature without trying to explain why. Usually involves math. “Narrow” Scientific theory: Explains why you usually see a particular thing in nature. The observations are indisputable facts and the theory is constantly being tested. “Broad” The main difference is the “why.” e.g. It’s germ theory because you can’t just throw math at it and figure out what disease bacteria will cause. (This is a very simplified explanation.)

12. Scientific Laws You can also call scientific laws facts. Law of conservation of energy Hooke’s law (how a spring coil moves) Newton’s law of universal gravitation (different from the theory of gravity because it doesn’t apply to things like black holes) Most laws look like math equations, but it might be weird math.

13. Questions Any questions about the slides? Any new questions?

14. New Questions What was the most dangerous dinosaur? Possibly the spinosaurus, which hunted on land and sea.

15. New Questions What is the most dangerous big cat? What is the most dangerous fish apart from sharks? What kinds of water snakes are venomous? What is the biggest snake in the world? Green anaconda is the heaviest (227 kg); reticulated python is the longest (10 m).