Question

analyzing the elements of a scientific method
read the following story and then answer the questions.
a scientist wants to find out why sea water freezes at a lower temperature than fresh water. the scientist goes to the library and reads a number of articles about the physical properties of solutions. the scientist also reads about the composition of sea water. the scientist travels to a nearby beach and observes the conditions there. the scientist notes the taste of sea water and other factors such as waves, wind, air pressure, temperature, and humidity. after considering all this information, the scientist sits at a desk and writes, \if sea water has salt in it, it will freeze at a lower temperature than fresh water.\ the scientist goes the laboratory and does the following:
a. fills each of two beakers with 1 liter of fresh water
b. dissolves 35 grams of table salt in one of the beakers
c. places both beakers in a freezer at a temperature of -1°c
d. leaves the beakers in a freezer for 24 hours.
after 24 hours, the scientist examines both beakers and fins the fresh water to be frozen. the salt water is still a liquid. the scientist writes in a notebook, \it appears that salt water freezes at a lower temperature than fresh water.\ the scientist continues, \i suggest that the reason sea water freezes at a lower temperature is that sea water contains dissolved salts, while fresh water does not.\
questions:

1. which statement(s) contain conclusions?
2. which statement(s) contains a hypothesis?
3. which statement(s) contain observations?
4. which statement(s) describe an experiment?
5. in which statement is the problem described?

Explanation:

1. A conclusion is a statement based on the results of an experiment. "It appears that salt water freezes at a lower temperature than fresh water." and "I suggest that the reason sea water freezes at a lower temperature is that sea water contains dissolved salts, while fresh water does not." are conclusions drawn from the experiment.
2. A hypothesis is a proposed explanation made on the basis of limited evidence as a starting - point for further investigation. "If sea water has salt in it, it will freeze at a lower temperature than fresh water." is a hypothesis.
3. Observations are facts or events noticed through the senses. "The scientist notes the taste of sea water and other factors such as waves, wind, air pressure, temperature, and humidity." and "After 24 hours, the scientist examines both beakers and finds the fresh water to be frozen. The salt water is still a liquid." are observations.
4. The steps "a. Fills each of two beakers with 1 liter of fresh water; b. Dissolves 35 grams of table salt in one of the beakers; c. Places both beakers in a freezer at a temperature of - 1°C; d. Leaves the beakers in a freezer for 24 hours." describe the experiment.
5. The problem is described as "A scientist wants to find out why sea water freezes at a lower temperature than fresh water."

Answer:

1. "It appears that salt water freezes at a lower temperature than fresh water." and "I suggest that the reason sea water freezes at a lower temperature is that sea water contains dissolved salts, while fresh water does not."
2. "If sea water has salt in it, it will freeze at a lower temperature than fresh water."
3. "The scientist notes the taste of sea water and other factors such as waves, wind, air pressure, temperature, and humidity." and "After 24 hours, the scientist examines both beakers and finds the fresh water to be frozen. The salt water is still a liquid."
4. "a. Fills each of two beakers with 1 liter of fresh water; b. Dissolves 35 grams of table salt in one of the beakers; c. Places both beakers in a freezer at a temperature of - 1°C; d. Leaves the beakers in a freezer for 24 hours."
5. "A scientist wants to find out why sea water freezes at a lower temperature than fresh water."