One scientist did an experiment with a meter stick and pencil. The steps of the experiment are listed below. Hold a meter stick
horizontally with one end on the nose and the other end pointing forward away from the body. Ask a friend to hold a pencil on the 50 cm mark of the meter stick. Look at the pencil and alternately open and close each eye. Observe how the pencil appears to move with respect to background objects. Repeat steps 3 and 4 by asking the friend to hold the pencil at 25 cm and 100 cm marks. Based on the experiment, what would the scientist most likely conclude? parallax shift remains the same at all distances of stars from Earth parallax shift depends on the size of the stars with respect to Earth parallax would be most effective in measuring distances to stars which are very far away from Earth parallax would be most effective in measuring distances to stars which are close to the Earth
Parallax would be most effective in measuring distances to stars which are close to the Earth.
Explanation:
In the experiment,
The parallax shift would decrease as the pencil would move further away from the scientist's eye, so option 1 would be invalid.
the size of the pencil remains constant, so option 2 would be invalid.
the parallax shift can be observed when the pencil has objects in the background to provide relation, that is to say, the shift of the pencil when seen relative to background objects; therefore, if we assume that the pencil is a star nearby to the Earth, and the background objects are stars that are further away, then the shift of, and thus, distance to the nearby star can be easily observed.
