ACT Science

SAT Question of the Day

The SAT question of the day is an Identifying Sentence Errors Question that has already been addressed on this blog: click here to see an explanation.

ACT Science Question of the Day

Science Questions on the ACT are not about memorizing facts, they are about finding information and being able to read charts.  They do not require you to know anything that is not given to you!

Passage II

    The Sun's path from sunrise to sunset varies with the time of year. A student performed the following experiments on three clear, sunny days at three- or four-month intervals throughout the course of a year to study the path of the Sun through the sky.

Experiment 1

    At a chosen Northern Hemisphere location, the student placed a stick vertically into the ground so that 1 meter of its length was left above ground. The student knew that the length of the shadow was related to the height of the Sun above the horizon and that the shadow would point away from the direction of the Sun. The length in meters (m) and direction of the shadow cast by the stick were measured one hour after sunrise (Shadow A), at mid-morning (B), at noon (C), at mid-afternoon (D), and one hour before sunset (E) on each of the three days. The direction of each shadow was determined by placing a magnetic compass at the base of the stick and aligning the north arrow with the north mark on the compass. The direction of each shadow was then determined by a comparison with the compass face markings. The results are recorded in Table 1.

Table 1
Shadow	Day 1		Day 2		Day 3
	Length (m)	Shadow  direction	Length  (m)	Shadow  direction	Length  (m)	Shadow  direction
A	5.0	SW	8.6	NW	6.8	W
B	1.2	W	2.9	NNW	1.7	NW
C	0.3	N	2.3	N	0.9	N
D	1.2	E	3.0	NNE	1.8	NE
E	5.0	SE	8.6	NE	6.9	E

Experiment 2     The following year, the student repeated Experiment 1 at a chosen location in the Southern Hemisphere. The results are in Table 2.

Table 2
Shadow	Day 1		Day 2		Day 3
	Length (m)	Shadow  direction	Length  (m)	Shadow  direction	Length  (m)	Shadow  direction
A	9.0	SW	5.0	NW	6.9	W
B	3.2	SSW	1.1	W	1.8	SW
C	2.5	S	0.3	S	1.0	S
D	3.2	SSE	1.1	E	1.8	SE
E	9.1	SE	5.0	NE	6.9	E

When the Sun is at an altitude 45° above the horizon, a vertical object will cast a shadow with a length equal to the object’s height. Which of the following days included a measurement taken when the Sun was at an altitude of 45°?

The first paragraph under Experiment 1 tells you that the stick (the vertical object) has 1 meter above the ground.  You must find a shadow length that is equal to the height in order to know that the Sun was at an altitude of 45° at that moment.  Check the charts.  There is only one shadow that is 1 meter long.  It is in the second chart (Experiment 2) under Day 3, Shadow C.  Circle it and look down at your answer choices.

A. Day 1 in Experiment 1
B. Day 1 in Experiment 2
C. Day 2 in Experiment 1
D. Day 3 in Experiment 2

The correct answer is (D).

For the ACT Question of the Day, visit http://www.act.org/qotd/.

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