1.2.5 Practice: Chemistry in the World Chemistry Sem 1 Points Possible:25

Question 2: Scientists Observe Patterns and Rules

Observations of the physical world lead to the discovery of patterns. Understanding patterns leads to the discovery of rules. Understanding rules leads to the discovery of how the physical world works.

a. Patterns in nature involve anything that happens over and over again. A pattern could repeat itself at a specific time of day, time of the month, or time of year. Describe one of these kinds of patterns. (Example: A full moon occurs every 28 days.) (1 point)

b. What rule does the pattern you picked above point to? (Example: The appearance of a full moon every 28 days means that the moon orbits the Earth every 28 days.) (1 point)
Question 3: The Scientific Method

a. The Question:

In 1988, three gray whales were trapped in Arctic ice. Television crews captured the frantic attempts of hundreds of people to save the whales. Eventually, a Soviet icebreaker and U.S. National Guard helicopters arrived to help free the whales. The cost of the rescue mission exceeded $5 million.

i. Write a scientific question related to the whale story. (1 point)


ii. Write a nonscientific question related to the whale story. (1 point)


b. The Hypothesis:

Your little sister asks you a scientific question: "Does chocolate milk come from brown cows?" In order to answer the question, you decide to form a hypothesis.

Explain whether or not the following statements are effective hypotheses.

i. Brown cows produce chocolate milk. (1 point)


ii. Brown cows never produce chocolate milk. (1 point)


iii. Brown cows produce white milk. (1 point)


c. The Experiment:

i. A student conducts an experiment to determine whether adding salt causes water to boil more quickly. The student plans to heat two pots of water and measure how long they take to boil. One pot has salt in it and the other does not. The pot of water with salt added is the experimental group. The pot of water without salt is the control group. For the boiling saltwater experiment described, list three things that would make the control group ineffective. (1 point)

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ii. How might data for this experiment be organized to help look for patterns? (1 point)


iii. Why is peer review important? (1 point)


Question 4: History of Chemistry

a. How did Aristotle's idea of matter differ from that of scientists? (1 point)


b. Why wasn't alchemy considered a "real" science? (1 point)


c. Why is modern chemistry considered scientific? (1 point)


Question 5: Chemicals in Our World

a. A sign above a supermarket display of oranges reads:

Organic Produce
No chemicals were used to harvest this fruit!

How accurate is this claim? Why or why not? (1 point)


b. Name one way chemicals can help the environment. (1 point)


c. Name one way chemicals can hurt the environment. (1 point)


Question 6: Chemicals and Safety

a. Name a chemical or product that was once considered safe but is now considered harmful. (1 point)


b. Name a chemical that is safe to use in food in small amounts. (1 point)


c. Why do chemists routinely test existing chemicals? (1 point)

Question 7: The Scientist and Society

a. How do ethical guidelines make science safer? (1 point)

b. How does government funding affect scientific progress? (1 point)

c. In what way do scientists help the government do its work? (1 point)

d. What obligations do scientists have to society? (1 point)