 ACT Science

## Intepreting Experiments Passages

These questions have a predictable pattern. These types of questions are usually stated in a variety of ways such as:

• Is the statement “_____” consistent with Figure 1?
• A researcher hypothesized that _______. Do the results of study 2 support this hypothesis?

A.Yes, because of statement A
B.Yes, because of statement B
C.No, because of statement A
D.No, because of statement B

Most students who miss these kinds of questions jump the gun by deciding quickly on Yes or No before really looking at the data. As I mentioned earlier, answering these questions requires interpreting the data presented in figures and text and deciding whether the data support or contradict the hypothesis.

If you do not understand the experiment setup from the visuals alone, skim the passage for the relevant information to understand the experiment set up.

Here is an ACT Science practice question, more specifically an example of an experimental design question: In experiment 2, which solution was the titrant and which solution was the sample solution?

Answering this question requires understanding what the titrant and sample solution were. In this case, the passage defines what a titrant is and what a sample solution is, but if you misread the passage, it’s easy to mix it up, especially since it’s just a bunch of liquid being mixed together.

#### Example 1

Consider the following hypothesis: In a circuit arranged as in Figure 1 containing a battery, a capacitor, and a constant resistance, as a capacitance increases, the time required to reach a given voltage across the capacitor increases. Do the experiments support this hypothesis?

A. Yes; in Experiment 1, as capacitance increased, the time required to reach a given voltage increased.
B. Yes; in Experiment 2, as capacitance increased, the time required to reach a given voltage increased.
C. No; in Experiment 1, as capacitance increased, the time required to reach a given voltage decreased.
D. No; in Experiment 2 as capacitance increased, the time required to reach a given voltage decreased.

Solution: According to table 2, as capacitance increases, time required to reach a certain voltage across the capacitor increases, so we can eliminate answer choices C and D.

Now, the only difference between the two remaining answer choices A and B is whether the statement came from experiment 1 or 2. Since the data came from Table 2 and Table 2 represented the data from Experiment 2, B is the answer.

#### Example 2

A scientist claims that the acceleration factor of Enzyme B is dependent on both enzyme and substrate concentration. Do the data in Figure 3 and 4 support her claim?

A. No; the acceleration factor is dependent on enzyme concentration, but not on substrate concentration.
B. No; the acceleration factor is not dependent on either enzyme concentration or substrate concentration.
C. Yes; the acceleration factor is dependent on enzyme concentration, but not on substrate concentration.
D. Yes; the acceleration factor is dependent on both enzyme concentration and substrate concentration.

Solution: Looking at figure 4 and at the line for Enzyme B (since the hypothesis claim refers to Enzyme B), we see that as enzyme concentration increases so does acceleration factor, until it sort of even outs or increases more slowly.

Figure 3 looks similar; looking at the line for Enzyme B, we see that as substrate concentration increases so does acceleration factor until it sort of even outs or increases more slowly.

So the acceleration factor for Enzyme B is dependent on both enzyme and substrate concentration.`Therefore, D is the right answer.

#### Example 3

Study 3
The annual wet deposition of $$Cu^{2+}$$ and of $$Zn^{2+}$$ for the 12-month period, in U g/m2 $$Ug/m^{2}$$ was calculated for the urban site (the source of the  $$Cu^{2+}$$ and $$Zn^{2+}$$ , and also for Rural Sites 1 and 2, located 50 km and 100 km east, respectively, of the urban site (see Figure below).

According to Study 3, as distance from the urban site increased, the annual wet deposition:
A. increased for both $$Cu^{2+}$$ and $$Zn^{2+}$$
B. increased for both $$Cu^{2+}$$ but decreased for $$Zn^{2+}$$

C. decreased for both $$Cu^{2+}$$ and $$Zn^{2+)$$
D. remained the same for both $$Cu^{2+}$$ and $$Zn^{2+}$$

Solution: The key mentions 3 sites, but nowhere in the Figure does it list the distances. We have to skim for this information. In the last sentence of the paragraph above Figure 4, it says that Rural Site 1 is 50 km from the urban site and Rural Site 2 is 100 km from the urban site.

Start ranking the sites in terms of increasing distance from the urban site: Urban site (0km since it is the site), Site 1 (50km), Site 2 (100 km).

Now, let’s start with one ion, Cu2+. As we progress from the urban site 1 to site 2, the bars get smaller, so the annual wet deposition decreases. So, for Cu2+ as distance increases, annual wet deposition decreases. Knowing this, we can eliminate answer choices A, B, & D. This only leaves us with C, which is the answer,

#### Example 4

Which of the following graphs illustrates the relationship between the heat released by the foods listed and change in water temperature?

Solution: This question asks you to evaluate the relationship that is given in a table and make it into a graph. Answer choice B shows a direct relationship, answer choice C shows an inverse relationship, and answer choices A and D show relationships that are neither inverse nor direct.

When you are asked to evaluate relationship, based on a table, first reorder the table in chronological order. This allows you to better see the relationship. Also, draw arrows to indicate increasing or decreasing such as I’ve done below:

I now know that it is a direct relationship, as change in water temperature increase, so does the heat released. I know the answer has to be B.

#### Example 5

Based on the figure, does S depend on the frequency of a sound wave of a given intensity?

A. Yes, because as the frequency increases, S increases.
B. Yes, because as the frequency increases, S remains constant.
C. No, because as the frequency increases, S increases.
D. No, because as the frequency increases, S remains constant.

Solution: The question is asking you to evaluate if S has a relationship with frequency across all intensity values?

Now, we need to locate S, and compare it to frequency. In such a complex graph, circling is your friend. See my beautiful, Picasso like, artwork below:

You will notice all of the S values are vertical lines. What this means is as frequency changes, the intensity of S at any value (S 10-8%, S 10-2%, S 10-1%, S 100% - it is fine to not understand what these values mean) remains the same. So we can eliminate, A and C because we know S does not increase- it stays the same.

Now to decide between B and D. Does S depend on frequency? Well since it doesn’t change when frequency does, the answer is No. So, D is the answer.