15. passive solar devices collect heat energy from the sun without themselves requiring extra energy to…

15. passive solar devices collect heat energy from the sun without themselves requiring extra energy to work. to provide extra heat for a house, the passive solar device absorbs heat energy during the day and radiates it when the temperature falls at night. which of the following experiments would best help determine which material radiates heat most slowly, thus making it suitable for a passive solar device? (1) place identical containers holding different materials in a sunny spot, and record their temperatures just at sundown and at regular intervals after sundown. (2) place identical containers holding different materials in a sunny spot, and record their temperatures at sunrise and sundown. (3) place different sized containers holding one type of material in a sunny spot, and record their temperatures at sundown and at regular intervals after sundown. (4) place different kinds of containers holding different materials in a sunny spot, and feel them before sundown and at regular intervals after sundown to see how warm they are. (5) place identical containers holding different materials in a shaded spot, and record their temperatures just at sundown and at regular intervals after sundown. 16. every magnet has a north pole and a south pole. the north pole of one magnet is attracted to the south pole of another magnet. suppose a bar magnet is cut in half across the middle. what poles will each one of the resulting magnets have? (1) two north poles only (2) two south poles only (3) one north pole only (4) one south pole only (5) one north pole and one south pole 17. ants are social animals that live together in a colony. each ant plays a part in helping the group survive. usually, a colony has one queen, who lays eggs. there are winged males, which develop from unfertilized eggs, and die soon after leaving the nest to mate with other queens. however, most of the ants are worker females that cannot lay fertilized eggs. their job is to find food and sometimes to fight to protect the colony. based on this information, which of the following statements best explains why there are fewer males than worker ants in an ant colony? (1) males do not live long, and only a few are required to fertilize a queen. (2) workers are so numerous that they crowd off the males. (3) the formation of wings requires a specialized environment. (4) winged males develop from unfertilized eggs. (5) winged males must sometimes fight to protect the colony. 18. for decades, scientists thought that people were born with all the brain cells they would ever have and that deteriorated or damaged brain cells were not repaired or replaced. however, recent research suggests that people may add billions of new brain cells from infancy through adolescence. even adults may maintain brain function by adding new cells. many scientists have had difficulty believing the new findings because these findings did not agree with long - standing ideas about the brain. which is an unstated assumption related to this paragraph? (1) scientists thought people were born with all the brain cells they would ever have. (2) scientists, like other people, sometimes have trouble changing long - held beliefs. (3) when brain cells are injured, they cannot repair or replace themselves. (4) recent research on brain cells is not very surprising. (5) even adults may be able to add new brain cells.

15. passive solar devices collect heat energy from the sun without themselves requiring extra energy to work. to provide extra heat for a house, the passive solar device absorbs heat energy during the day and radiates it when the temperature falls at night. which of the following experiments would best help determine which material radiates heat most slowly, thus making it suitable for a passive solar device? (1) place identical containers holding different materials in a sunny spot, and record their temperatures just at sundown and at regular intervals after sundown. (2) place identical containers holding different materials in a sunny spot, and record their temperatures at sunrise and sundown. (3) place different sized containers holding one type of material in a sunny spot, and record their temperatures at sundown and at regular intervals after sundown. (4) place different kinds of containers holding different materials in a sunny spot, and feel them before sundown and at regular intervals after sundown to see how warm they are. (5) place identical containers holding different materials in a shaded spot, and record their temperatures just at sundown and at regular intervals after sundown. 16. every magnet has a north pole and a south pole. the north pole of one magnet is attracted to the south pole of another magnet. suppose a bar magnet is cut in half across the middle. what poles will each one of the resulting magnets have? (1) two north poles only (2) two south poles only (3) one north pole only (4) one south pole only (5) one north pole and one south pole 17. ants are social animals that live together in a colony. each ant plays a part in helping the group survive. usually, a colony has one queen, who lays eggs. there are winged males, which develop from unfertilized eggs, and die soon after leaving the nest to mate with other queens. however, most of the ants are worker females that cannot lay fertilized eggs. their job is to find food and sometimes to fight to protect the colony. based on this information, which of the following statements best explains why there are fewer males than worker ants in an ant colony? (1) males do not live long, and only a few are required to fertilize a queen. (2) workers are so numerous that they crowd off the males. (3) the formation of wings requires a specialized environment. (4) winged males develop from unfertilized eggs. (5) winged males must sometimes fight to protect the colony. 18. for decades, scientists thought that people were born with all the brain cells they would ever have and that deteriorated or damaged brain cells were not repaired or replaced. however, recent research suggests that people may add billions of new brain cells from infancy through adolescence. even adults may maintain brain function by adding new cells. many scientists have had difficulty believing the new findings because these findings did not agree with long - standing ideas about the brain. which is an unstated assumption related to this paragraph? (1) scientists thought people were born with all the brain cells they would ever have. (2) scientists, like other people, sometimes have trouble changing long - held beliefs. (3) when brain cells are injured, they cannot repair or replace themselves. (4) recent research on brain cells is not very surprising. (5) even adults may be able to add new brain cells.

Answer

15.

Explanation:

Step1: Control variables

To determine which material radiates heat most slowly for a passive - solar device, we need to control variables. Identical containers should be used to ensure that container - related factors do not affect the result. The materials should be different, and the containers should be placed in a sunny spot to absorb heat during the day. Recording temperatures at sundown and after sundown helps to observe the heat - radiation process.

Step2: Analyze options

Option (1) only records temperature at sundown and after sundown without a reference point at sunrise. Option (2) records at sunrise and sundown but may not fully capture the heat - radiation process after sundown. Option (3) uses different - sized containers which introduce an extra variable. Option (4) relying on feeling is not a precise measurement. Option (5) places containers in a shaded spot, so they do not absorb heat from the sun effectively. Option (2) is the best as it gives a starting point (sunrise) and an end - point (sundown) and can show the change in temperature due to heat radiation after sundown.

Answer:

(2)

16.

Explanation:

When a bar magnet is cut in half across the middle, each new magnet will have a north pole and a south pole. This is because magnetic poles always occur in pairs. A single magnetic pole (magnetic monopole) has not been found in nature. Each piece of the magnet will re - establish its own magnetic field with both a north and a south pole.

Answer:

(5)

17.

Explanation:

In an ant colony, males are mainly required to fertilize the queen. Since only a few males are needed for this task, there are fewer males compared to worker ants which have multiple tasks like foraging, protecting the colony etc. Worker ants are numerous because of their diverse and essential roles in the daily life of the colony.

Answer:

(1)

18.

Explanation:

The fact that many scientists have had difficulty believing the new findings because they did not agree with long - standing ideas about the brain implies that scientists, like other people, sometimes have trouble changing long - held beliefs. The other options are either stated in the passage or are not assumptions related to the difficulty of scientists in accepting new findings.

Answer:

(2)