Catalyst

1. Catalyst *No calculators today Melvin wanted to see if getting more hours of sleep at night would improve his focus the next day. 1. What is the independent variable? 2. What is the dependent variable? 3. What could a controlled variable be?

2. Agenda

3. Consumer Reports Research Project • The purposes of the project: • 1. To practice using the scientific method to solve a real-world problem • 2. To learn how to write lab reports • 3. To make a recommendation to buy a certain product • Ex. The video recommends that we buy Energizer Lithium batteries because they last the longest. • If you are testing paper towels, you should tell us which brand to buy by the end of your experiment. • Rubric • Let’s watch the video again….

4. Consumer Reports Research Project • Group members: Susie Scientist, Charlie Chemist, Peter Physicist • The product we will be testing is… AA batteries • The question we will be answering is… Which brand of AA batteries lasts the longest for the money? • In order to test our product, we need at least three different types or brands. They are as follows: • 1. Rayovac • 2. Energizer • 3. Duracell

5. Consumer Reports Research Project • The question we will be answering is… Which brand of AA batteries lasts the longest for the money? • The independent variable in our experiment is… the different brands of batteries • The dependent variable in our experiment is… the length of time the batteries last • The way we will test the dependent variable is to… take pictures with cameras with the different batteries in them to see which batteries will take the most pictures before dying

6. Agenda

7. Scenario #1: The CD Burner • Your friend has found a new free CD-burning program. He claims it can burn CDs much better than your old program. You put the new program on your computer, and find that you can burn a CD in 3 minutes flat. Your friend says, “See? I told you it was better.” • a) do you support your friend’s claim? why or why not? • b) what would be the variable in this problem? • c) what would be the control? • d) what other controls might you suggest could be added?

8. Scenario #2: The Diabetes Test • Your doctor has suggested that you get a test for diabetes. Diabetes is a condition where there is too much sugar in the blood. If you have diabetes, some of that sugar will come out in your urine. This test uses a simple dipstick to show whether or not there is sugar in the urine. After providing a urine sample, the doctor dips in the dipstick, and right before your eyes you can see that the dipstick turns bright red. The doctor says, “a-HA! Just as I thought!” • a) what is the conclusion? • b) what is the hypothesis? • c) what is the variable? • d) what is the control? • e) what is MISSING from this experiment?

9. Scenario #2 Continued: The Diabetes Test • In a related experiment, the doctor performs the same test, with the same kind of dipsticks (fresh ones, of course) on two more substances: water with 7 tablespoons of sugar stirred in; and plain tap water. Results from this test show that the sugar-water dipstick turns bright red. The tap water dipstick turns green. What does this do to your interpretation of the previous experiment? • a) what is the role played by the tap water? • b) what is the role played by the sugar water?

10. Scenario #3: Rust • A scientist set up the following experiment to try to tell the effect of acid rain on car paint. She arranged for there to be four cars of similar age, body type, and paint job to be monitored in four different places around the continent. Car #1 was in Oregon; car #2 was in Toronto, Ontario; car #3 was in Akron, Ohio; and car #4 was in Area 51, Nevada. With each car, she counted the number of rust spots that developed after one year. Her results are shown in the following table:

11. Scenario #3: Rust • a) what are the controls in this experiment (if any)? • b) what are the variables in this experiment? • c) what is the hypothesis in this experiment? • d) what does this experiment prove? • e) what is this experiment MISSING?

12. Scenario #4: The Bilingual Dog • Mr. Jones has taught his dog Rover to understand French. Mr. Jones noticed that every evening, after dinner, when he went to the door with his coat on and said "Walkies," Rover immediately understood and came running. Mr. Jones was going to France for the summer, and, as an experiment in international understanding, decided to teach Rover French. He started to say "Allons-y!” instead of "Walkies." To his delight, Rover very quickly understood and came running. From this, Mr. Jones concluded that Rover did indeed understand French. • a) What is Mr Jones's hypothesis? • b) what is the main observation made by Mr Jones? • c) what is (are) the variable(s) here? • d) what is (are) the control(s) here? • e) does this experiment prove Mr Jones’ hypothesis? Why or why not? • f) what further explanations might be possible for the main observation? Is this the only explanation? • g) Can we devise a test to discriminate between these possibilities? How?

13. Scenario #5: Penicillin • In 1928, Sir Alexander Fleming was studying Staphylococcus bacteria growing in culture dishes. He noticed that a mold called Penicillium was also growing in some of the dishes. A clear area existed around the mold because all the bacteria that had grown in this area had died. In the culture dishes without the mold, no clear areas were present. • Fleming hypothesized that the mold must be producing a chemical that killed the bacteria. He decided to isolate this substance and test it to see if it would kill bacteria. Fleming transferred the mold to a nutrient broth solution. This solution contained all the materials the mold needed to grow. After the mold grew, he removed it from the nutrient broth. Fleming then added the nutrient broth in which the mold had grown to a culture of bacteria. He observed that the bacteria died. • a. State the Question that Sir Fleming was trying to answer. • b. What was Fleming's hypothesis? • c. How was the hypothesis tested? • d. Should the hypothesis be supported or rejected based on the experiment? • e. This experiment led to the development of what major medical advancement?

14. Scenario #6: The Strange Case of Beriberi • In 1887 a strange nerve disease attacked the people in the Dutch East Indies. The disease was beriberi. Symptoms of the disease included weakness and loss of appetite, and victims often died of heart failure. Scientists thought the disease might be caused by bacteria. They injected chickens with bacteria from the blood of patients with beriberi. The injected chickens became sick. However, so did a group of chickens that were not injected with bacteria. • One of the scientists, Dr. Eijkman, noticed something. Before the experiment, all the chickens had eaten whole-grain rice, but during the experiment, the chickens were fed polished rice. Dr. Eijkman researched this interesting case. He found that polished rice lacked thiamine, a vitamin necessary for good health. • a. State the Question that Dr. Eijkman was trying to answer. • b. What was the initial hypothesis? • c. How was this hypothesis tested? • d. Should the hypothesis be supported or rejected based on the experiment? • e. What should be the new hypothesis?

15. Agenda

16. Exit Slip Tell whether the following are observations or inferences, and IF it is an observation, tell whether it is qualitative or quantitative. • 1. He is angry at his brother. • 2. He is six feet tall. • 3. What is the difference between a conclusion and a hypothesis?