Science Study Guide for the ACT

Scientific Investigation

Scientific investigation is the process of asking questions, formulating hypotheses, designing experiments, collecting data, and drawing conclusions based on evidence. Understanding the principles of scientific investigation is essential for success on the ACT Science section, as it forms the basis for much of the scientific data presented on the test.

Locate Textual Information about an Experiment

You may be presented with scientific texts that describe experimental design, data collection methods, and the significance of the results. To prepare for this section, it is important to practice reading and comprehending scientific texts and to be able to identify and extract key information quickly and efficiently.

Tool Function

Understanding the function of scientific tools is essential for success on the Science section of the ACT, as many of the experimental setups and data collection methods involve the use of specialized equipment.

It is important to have a strong understanding of the different types of scientific tools and equipment, including microscopes, pipettes, spectrometers, and other devices. You should also be able to identify the specific functions of each tool and be able to explain how they are used to collect data or perform experiments.

Methods

Many of the scientific passages and questions on the ACT are centered around experimental design and methods, so it is important to understand experimental methods. You must have a strong understanding of the scientific method, including the steps involved in designing and carrying out experiments. You should also be able to identify the different types of experimental methods, such as observational studies, randomized controlled trials, and case-control studies.

Experimental Design

You may be presented with scientific passages that describe different experimental methods and be asked to analyze the strengths and weaknesses of these methods. You may also be asked to design your own experiments based on given parameters. To prepare for this, it is important to practice designing and analyzing experimental methods and to be able to identify the appropriate experimental method for a given research question.

Controls in Experiments

A control group is a crucial aspect of experimental design, as it allows researchers to isolate the effects of the independent variable on the dependent variable, and to rule out alternative explanations for the observed results.

You should have a strong understanding of the purpose and function of control groups and variables in scientific experiments. You should also be able to identify the different types of controls used in experiments, such as placebo controls, negative controls, and positive controls.

placebo controls—Participants in the experimental group may receive a placebo, which is an inert substance or treatment that has no therapeutic effect. The placebo is designed to resemble the actual treatment being tested, but it lacks the active ingredients or mechanisms of action.
negative controls—This type of control is used in scientific experiments to establish a baseline or reference point for comparison. A negative control is not exposed to the treatment or condition of interest.
positive controls—Like a negative control, this group is not exposed to the treatment or condition under study. However, they are exposed to a treatment or condition that is expected to produce a response that is the same as the treatment or condition being tested.

Compare and Contrast Experiments

Comparing and contrasting experiments is an essential skill for success on the Science section of the ACT, as it allows you to understand the strengths and weaknesses of different experimental designs and methods.

You may be presented with scientific passages that describe different experiments and be asked to compare and contrast the experimental design, methods, and results of these experiments. You may also be asked to identify the strengths and weaknesses of different experimental designs and methods and to determine which design would be most appropriate for a given research question. To prepare, it is important to practice analyzing and comparing experimental designs and to be able to identify the appropriate experimental design for a given research question.

Make Predictions

Predictive reasoning is an important aspect of scientific investigation, as it allows researchers to make informed decisions and plan experiments based on expected outcomes.

To develop this skill, it is important to have a strong understanding of scientific concepts and principles, as well as the ability to analyze and interpret scientific data. You should also be able to identify patterns and trends in scientific data and use this information to make predictions about future events or outcomes.

You may be presented with scientific passages or data sets and be asked to make predictions about future events or outcomes based on this information. You may also be asked to analyze trends in data and make predictions about how changing certain variables might affect the outcomes of an experiment. To prepare, you should practice analyzing and interpreting scientific data and ensure you are able to identify patterns and trends that may be relevant to making predictions.

Experimental Conditions

In order to accurately study a scientific phenomenon, it is essential to carefully control the variables that may affect the outcome of an experiment.

You should be familiar with the different types of experimental conditions, including:

independent variable—This is the factor or condition that is deliberately manipulated or controlled by the researcher to observe its effect on the dependent variable.
dependent variable—This is the factor or outcome that is measured, observed, or recorded by the researcher. It is expected to change as a result of the manipulation of the independent variable.
control variable—This is the factor or condition in a scientific experiment that is intentionally kept constant or unchanged throughout the study. These variables are carefully controlled to ensure that they do not influence the relationship between the independent variable and the dependent variable.

You should also understand the importance of these concepts regarding experimental design:

randomization—Randomization in experimental design serves to minimize bias and ensure that the allocation of subjects or treatments is unbiased and statistically representative of the population being studied. Randomization involves assigning participants or experimental units to different groups or conditions in a random and unpredictable manner.
replication—Replication involves repeating an experiment or study multiple times using independent samples or subjects to ensure the consistency of the results. This is a critical aspect of experimental design in scientific studies, as it enhances the reliability, robustness, and validity of the findings.
blinding—This is also known as masking and is a technique used in experimental design to minimize bias and ensure the integrity of the study. It involves withholding certain information from participants or researchers involved in the experiment to prevent their knowledge or expectations from influencing the results.

Stating a Hypothesis

A hypothesis is an educated guess or prediction about the outcome of an experiment or study. It is a statement that can be tested and either supported or rejected by the results of the experiment.

You should understand how to formulate a hypothesis that is both testable and specific. A good hypothesis should clearly state the relationship between the independent and dependent variables in the experiment. It should also be based on prior research or observations and should be supported by evidence.

You may be presented with scientific passages or data sets and be asked to identify hypotheses or formulate your own hypotheses based on the given information. It is important to practice formulating hypotheses based on scientific data and to understand how to create hypotheses that are both testable and specific.

Alternate Testing Methods

You may be presented with scientific passages or data sets that describe a hypothesis and the methods used to investigate it. You may be asked to identify potential limitations of the chosen testing method or to suggest alternate testing methods that could provide more reliable data. To prepare, it is important to have a strong understanding of the scientific method, the various types of testing methods available, and the advantages and limitations of each method. Practice analyzing and interpreting scientific data and applying this knowledge to hypothetical scenarios.

Precision and Accuracy

In science it is essential to measure quantities as accurately and precisely as possible. Precision refers to the consistency and reproducibility of measurements, while accuracy refers to how closely a measured value matches the true value.

You should understand the difference between precision and accuracy and how to evaluate both in scientific measurements. You should also understand the various factors that can impact measurement precision and accuracy, such as the reliability of the measuring tools and the skill of the person taking the measurement.

Determine Additional Actions

In scientific research, it is common to encounter unexpected results or to identify areas where additional investigation is needed. You should be prepared to analyze scientific data and make informed decisions about what additional actions to take.

You may be presented with scientific passages or data sets that require you to analyze and interpret data and then determine what additional actions, if any, are necessary. This could involve making hypotheses, proposing new experiments or investigations, or identifying areas where further data collection is needed.