Self-paced
P1
One of the foundations of scientific research is that an experimental result is credible only if it can be replicated—only if performing the experiment a second time leads to the same result. ███
Foundation of science ·
Experimental results are credible only if they are replicable
Replicable = doing experiment again leads to same result.
Problem ·
Somm. and Ott (S and O) came up with a new physical system
In this system, the tiniest change in starting conditions can change results radically. (What does this mean? Not sure.) This system can be represented by a computer model involving a particle's motion within a force field. (Not sure what this means either.)
P2
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Analogy ·
S and O's new system is similar to riddled basins of attraction
Definition of basin of attraction ·
Bodies of water have basins of attaction
The basin for a particular body of water = area of land where, whenever water is spilled on it, it goes toward that body of water.
P3
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Definition of riddled basins ·
Can't predict where water will flow for some points in between basins
The boundaries between these basins are riddled with physical irregulataries, which is why you can't tell where the water will flow. Need to spill the water at a point and observe. If you spill at any other point, even one right next to it, the water might flow toward a different body of water.
P4
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S and O's system ·
The riddled boundary expands to every single point
So, rather than just the boundary line between two bodies of water being riddled, every point in the whole system is riddled. You can't tell even the general destination of a particle from any starting point.
Distinction between S and O's system and chaos ·
In chaos, you can predict general destination, but not path or exact destination
In S and O's system, you can't predict any of the three things.
P5
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Implication of S and O's system ·
Other similar systems might exist, and if so, this would question the replication requirement
It's possible that some experiments can't be replicated because even the slightest, unnoticeable change in starting conditions leads to different results.
Passage Style
Problem-analysis
Single position
28.
Which one of the following ██ ████ ███████ ███ ██ ███
a
A scientist is ██████ ██ █████████ ██ ██████ ███████ █████████ ████ ██████ ██ █ ██████████ ████████ ████████ ███████ ███ ████████ ██████ ██ ████████████ ██████████ █████ █████████ ███ ████████ ██████ ███ █████ █████ ██ ████ ███ ███████ ████████ ██████████ ████ ███ ██ ████ ███████ ███ ████ ██ ████ ███████████
Not an example, because we wouldn’t know that starting conditions “are in fact exactly the same” in a system like Sommerer and Ott’s.
b
A scientist is ██████ ██ █████████ ██ ██████ ███████ █████████ ████ ██████ ██ █ ██████████ ████████ ████████ ███████ ███ ████████ ██████ ██ ████████████ ██████████ █████ ██ ██ ██████████ ██ █████ █████ ████████ ██████████ ████ ███ ██ ████ ███████ ███ ████ ██ ████ ███████████
This is the best answer. (B) involves a situation in which we can’t bring about the exact same starting conditions. This is exactly what we’d expect to happen if we’re in a system where
c
A scientist is ██████ ██ █████████ ██ ██████ ███████ █████████ ████ ██████ ██ █ ██████████ ████████ ████████ ███████ ███ ████████ ██████ ██ ████████████ ██████████ █████ ██ ██ ██████████ ██ ███████ ████████ ██████████ ████ ███ ████ █████████████ ███ ████ ████ ███ ██████████ ██ ███ █████
“Even approximately” is what makes this answer wrong. Although in Sommerer and Ott’s system, we cannot be sure that our starting conditions don’t have a small, undetectable difference, this doesn’t mean we can’t be sure that the starting conditions are generally about the same.
d
A scientist is ████ ██ █████████ ████ ██████ ███████ █████████ ███████ ██ █ ██████████ ████████ ████████ ███████ ██ ██ ████████ ██ ████████████ █████████ ███ ████████ ████ ██████ ███ ████████ ██████████ ████ █████████████ ████ ███ ██████████ ██ ███ █████
Not an example, because in Sommerer and Ott’s system, we wouldn’t be able to get the same results every time. The results would be radically different based on even tiny, undetectable changes in starting conditions.
e
A scientist is ████ ██ █████████ ████ ██████ ███████ █████████ ███████ ██ █ ██████████ ████████ ████████ ███████ ██ ██ ████████ ██ ████████████ █████████ ███ ████████ ███████ ███ ████ ████ ███ ██████ ██ ████ ██ █████ ███ ███ ████████ ██ █████ ██████ █████████████ █████████ ██ ███ ████████ ██████████ ██ ███ ███████████
Not an example, because in Sommerer and Ott’s system, we wouldn’t be able to get the same results every time. The results would be radically different based on even tiny, undetectable changes in starting conditions.