IMSO 2005 Science Taiwan Selection Second Round — Experiment

Experiment I. Base your answers to questions 31 through 35 on the experiment described below.

Heat was applied at a constant rate to a solid substance under controlled conditions. The temperature of the substance was recorded every 3 minutes. These data are recorded in the table below.

|Time (min)|0|3|6|9|12|15|18|21|24|27|30|
|---|---|---|---|---|---|---|---|---|---|---|---|
|Temperature (°C)|12|14|16|16|16|16|20|24|28|32|36|

31. Use the grid above to construct a line graph from the data in the table. Follow the steps below.

a. Use Xs to plot the data for time and temperature. (1 point)

b. Draw a solid line that connects the Xs. (1 point)

32. Provide an appropriate title for the graph. (2 points)

Title: ____________________

33. According to your graph, what would the temperature of the substance be at 23 minutes? (2 points)

34. What is the independent (manipulated) variable in this experiment? (2 points)

35. If heat was added at a constant rate to the solid substance, why did the temperature remain at 16°C for approximately 6 minutes? (2 points)

The original grid has time 0–30 minutes and temperature 10–40°C. The source splits the word “Temperature” across lines and prints “1 points”; these layout/grammar artifacts are normalized above. The stated “approximately 6 minutes” is retained; the table plateau actually spans minutes 6–15.

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Experiment II. Base your answers to questions 36 through 39 on the information and graph below.

You perform an experiment growing three types of plants in equal amounts of soil. Three different types of plants are used. Each plant is 10 centimeters tall at the beginning of the experiment. The three plants are given 4 milliliters of water every day for 20 days. The results of the experiment are shown on the graph.

Graph: “Changes in Plant Height Over a 20-day Period.” Horizontal axis: Days. Plant 1 is solid, Plant 2 dotted, and Plant 3 dashed, as in the original legend.

36. Which plant was the tallest at the end of the 20-day period? (2 points)

37. Other than at the beginning of the experiment, on what day were plant 2 and plant 3 the same height? (2 points)

38. Which plant grew at the slowest rate from day 0 to day 5? (3 points)

39. During which time interval did plant 1 become taller than plant 3? (3 points)

A. Day 0–5

B. Day 6–10

C. Day 10–15

D. Day 15–20

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Experiment III. Base your answers to questions 40 and 41 on the information and on the diagram below.

A student set up the experiment below to learn about plant growth. The student added a different amount of water to four identical containers, each containing four seeds in 100 cubic centimeters of soil. All of the containers were placed in the same sunny location.

The four containers have water amounts 0 mL, 10 mL, 20 mL and 40 mL, respectively; each contains 100 cm³ of soil and four seeds. The source does not specify a daily watering schedule.

40. State a hypothesis being tested in this experiment. (4 points)

41a. Identify one variable that is being held constant in this experiment. (3 points)

41b. Explain why this variable needs to be held constant. (3 points)

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Experiment IV. Base your answers to questions 42 through 44 on the diagrams and data table below.

The diagrams show the REST POINT and STRETCHED positions, with a centimeter ruler and an attached mass labeled 100 g. The original drawing duplicates the letter “g”; this is preserved in the panel.

|Attached mass (g)|Distance spring is stretched (cm)|
|---|---|
|100|3|
|200|6|
|300|9|
|400|12|
|500|15|
|1000|30|

42. State the relationship between the mass attached to the end of the spring and the length the spring is stretched. (3 points)

43. Predict how many centimeters the spring will stretch if a total mass of 700 grams were attached. (3 points)

44. What mass would be needed to stretch the spring to a length of 60 cm? (4 points)

The source phrase “length of 60 cm” is retained. The table and key treat this as extension, which differs from total spring length.

Original source panels: