Understanding the Science Section of the Act - Everything You Need to Know

April 25, 2024
4 min read

Preparing for the ACT is a crucial step for high schoolers dreaming of college, and tackling the science section can seem daunting. It's not just memorizing science facts; it's about applying your knowledge in smart ways. 

This guide is your key to understanding the science section of the ACT. It simplifies the process by breaking down the types of science questions you'll encounter, delving into the specific topics you need to master, and providing practical tips to enhance your score in the science section.

We even explain basic concepts, like the difference between a line, a line segment, and a ray, to strengthen your foundation. With this guide, you're not just preparing for the ACT; you're setting yourself up for future success in science. 

It's designed to transform your worries into confidence, providing all the necessary tools and knowledge to conquer the ACT science section and beyond. So, dive in with us, and let's turn those challenges into opportunities for growth and learning.

What Science Is on the ACT?

The ACT Science section assesses students' abilities to interpret, analyze, and solve problems using concepts from biology, chemistry, physics, and Earth/space sciences. It tests how well students can apply scientific knowledge and critical thinking to real-world scenarios rather than just recalling facts. 

Success in this section requires a good understanding of these subjects and strong analytical skills. It aims to measure readiness for college science courses.

What Science Topics Will Be Given in the Exams?

Understanding the range of topics covered in the ACT Science section can significantly enhance your preparation strategy. Here’s a closer look at the specific subjects and examples of topics you might encounter:


  1. Cell Structure and Function: Understanding the various parts of a cell and their roles.
  2. Photosynthesis and Cellular Respiration: How plants make their food and how cells use oxygen to release energy.
  3. Genetics and Heredity: The study of genes and how traits are passed from one generation to the next.
  4. Evolution and Natural Selection: How species change over time and adapt to their environment.
  5. Ecosystems and Ecological Relationships: The interactions between organisms and their environments.
  6. Biomes and Climate: Different global ecosystems and how climate affects them.
  7. Human Body Systems: Understanding the structure and function of various body systems.
  8. Diseases and Immune Response: How diseases affect the body and how the immune system responds.
  9. Biotechnology and Genetic Engineering: The use of technology in modifying living organisms for human purposes.
  10. Population Biology: The study of populations, their sizes, and distribution.


  1. Atomic Structure: Understanding the components of atoms and how they form elements.
  2. Periodic Table Trends: How elements are organized and the significance of their placement.
  3. Chemical Bonds and Reactions: The different types of chemical bonds and how substances react.
  4. States of Matter: The characteristics of solids, liquids, gases, and plasma.
  5. Acids and Bases: Properties of acids and bases and how they react with each other.
  6. Stoichiometry: Calculations involving the mass relationships between reactants and products in chemical reactions.
  7. Thermochemistry: The study of energy changes during chemical reactions.
  8. Equilibrium and Kinetics: How chemical reactions reach equilibrium and the rate at which they occur.
  9. Solutions and Solubility: How substances dissolve and factors affecting solubility.
  10. Gas Laws: The behavior of gases and the laws that describe their properties.

Each of these topics requires not only a basic understanding of the concepts but also the ability to apply this knowledge to analyze and solve problems. By familiarizing yourself with these topics and practicing these skills, you can approach the ACT Science section with confidence and readiness for the challenges it presents.

Tips on How to Ace the ACT Science Section

To ace the ACT Science section, focus on interpreting graphs and tables, understand scientific research basics, manage your time efficiently, and use elimination to improve answer accuracy. 

Familiarize yourself with scientific language through journals and practice with past ACT tests. Keep basic science principles fresh, concentrate on the questions asked, stay calm and confident, and review your answers if possible.

  • Practice Interpreting Graphs and Tables: Since the test heavily features data representation, becoming comfortable with these elements is crucial.
  • Understand Scientific Investigation: Know the basics of how scientific research is conducted, including variables, controls, and conclusions.
  • Time Management: Learn to quickly digest scientific passages and data to answer questions within the time limit.
  • Use Process of Elimination: Narrow down choices to increase your chances of selecting the correct answer.
  • Read Scientific Journals: Familiarize yourself with the format and language of scientific discussions.
  • Practice Past Papers: Use previous ACT tests to get a feel for the types of questions asked.
  • Stay Updated on Basic Science Principles: Though advanced knowledge isn't required, understanding fundamental concepts in biology, chemistry, physics, and Earth/space sciences is helpful.
  • Focus on the Question: Sometimes, additional information is provided that isn't necessary to answer the question. Focus on what's being asked.
  • Stay Calm and Confident: Confidence can significantly affect your performance. Stay positive and trust your preparation.
  • Review Your Answers: If time allows, go back and review your answers, especially for questions you were unsure about.

Difference Between Line, Line Segment, and Ray

Exploring the fundamental concepts of geometry, let's investigate the distinctions between a line, line segment, and ray, focusing on their endpoints, length, direction, and how each is represented.

Feature Line Line Segment Ray
Endpoints No endpoints Two endpoints One endpoint
Length Infinite Finite Infinite
Direction Infinite in both directions Fixed direction Direction
Representation --

Important Notes:

  • A line extends infinitely in both directions without any endpoints.
  • A line segment has two distinct endpoints, determining its length.
  • A ray starts at a point and extends infinitely in one direction.

Line Segment Problems: Example Exam Questions

Here are some example questions about line segments that you might find on a test, to help you see how much you know about this basic geometry idea.

  1. Question: Given a line segment with endpoints at (2,3) and (10,7), find the length of the line segment.
  • Solution: Use the distance formula sqrt((x2 - x1)^2 + (y2 - y1)^2) to calculate the length.
  1. Question: If a line segment is bisected, what is the relationship between the original line segment and its two halves?
  • Solution: The two halves are congruent; each half has the same length as the other.
  1. Question: How do you find the midpoint of a line segment with endpoints (4, -2) and (12, 8)?
  • Solution: Use the midpoint formula ((x1+ x2) / 2, (y1 + y2) / 2) to find the midpoint.
  1. Question: A line segment is divided into a ratio of 2:3. How do you find the point of division?
  • Solution: Use the section formula to calculate the coordinates of the dividing point.


In this FAQs section, we'll answer some common questions about the science part of the ACT.

1. How Much Science Do You Need to Know for the ACT Test?

The ACT Science section does not test specific science content knowledge but rather your ability to interpret and analyze scientific information. A solid understanding of basic principles from biology, chemistry, physics, and Earth/space sciences is beneficial, but the focus is on scientific reasoning skills.

2. Is Science on the ACT Difficult?

The difficulty of the ACT Science section varies from student to student, depending largely on their comfort with scientific reasoning and data analysis. With practice, many students find that they can improve their performance significantly, even if they don't consider themselves strong in science subjects.

Final Thoughts

Understanding the science section of the ACT challenges students to apply critical thinking skills to scientific scenarios, making it a unique component of the exam. Focusing on analytical skills over rote memorization offers a different kind of academic challenge, one that can be mastered with the right approach and preparation.

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