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Question of the Day: ACT Science
As part of an engineering competition, a group of students are asked to design a flying robot that simulates the way real birds fly. Below, three of the students give their explanations for how bird flight occurs.
Student 1:
Birds are able to fly due to the shape of their wings. Bird wings are convex on their upper sides, while their lower sides are usually concave. This type of shape is called an airfoil. When a wing travels through the air, air passing over the top of the wing must travel a greater distance than air passing under the wing. The stream of air passing over the wing and the stream of air passing under the wing meet together at the tail end of the wing. In order for both streams of air to meet at the same point behind the wing, the air above the wing, which travels a greater distance, must travel faster than the air below the wing.
When a volume of air travels more quickly over a distance, its molecules are spread out over a greater distance. As a result, the air traveling over the top of a wing has a lower pressure than the air traveling under the wing. Because the wing has a region of low pressure above it and a region of relative high pressure below it, it experiences a net upward force. When this upward force is greater than or equal to the bird's weight, or the force exerted on a bird by gravity, the bird is able to fly.
The magnitude of the upward force depends on the speed at which air flows across the wing and on the corresponding difference in pressure over and under the wing. When birds flap their wings, they increase the speed of air flowing across their wings, thus producing a greater upward force.
Student 2:
There are two components to bird flight: lift and thrust. "Lift" refers to the upward force that allows a bird to stay aloft in the air despite its weight, while "thrust" refers to the horizontal force that allows a bird to move forward through the air. Birds are able to fly because they do not hold their wings perfectly horizontally. Instead, their wings are angled slightly upward. The angle at which a wing is inclined upward, with respect to the horizontal, is called its "angle of attack."
Air is not an ideal gas; instead, it has viscosity. This means that the air flowing close to a solid object tends to follow the curves of that object. When air encounters a bird's wing, it follows the incline of the wing. Because of the wing's angle of attack, the air is directed downward and back. The air continues to move downward, even after it has left the wing. This movement of the air creates an opposing force that pushes the bird upward and forward.
Thus, the angle of attack of a bird's wings accounts for both the lift and thrust components of a bird's flight.
Student 3:
Birds are able to fly because the way in which they move their wings allows them to create a net movement of air downward and backward. The flapping of a bird's wings can be understood as being composed of two parts: a downstroke, during which the bird moves its wings down, and an upstroke, during which the bird moves its wings up. During a downstroke, a bird displaces a quantity of air downward and behind it. During an upstroke, however, the bird's wings are angled upward in a way that displaces less air, and its wing feathers rotate to allow air to pass through them. Thus, on the upstroke, the bird much exerts less force on the air than it does on the downstroke.
The amount of force exerted on an object can be calculated by multiplying the mass of the object by the acceleration it experiences. Given that Student 3's explanation is correct, which of the following situations would allow a bird's body to experience the greatest upward force?
The bird's wings displace 
The bird's wings displace 
The bird's wings displace 
The bird's wings displace 
Facing the ACT is stressful for even the best students. You know that this test can have a major impact on the success of your college applications. Unlike your GPA, extracurricular activities, or letters of recommendation, the ACT Science test is totally objective. For example you might attend a school that grades students with far more rigor than another. A university needs an objective measure to distinguish your transcript from a student with the same GPA, but from a less rigorous program. The ACT is just that tool.
You also know that the ACT is not like tests you have taken in classes. Instead, it is testing the development of your critical thinking skills over the past four years. Four years on one exam day! Whether you need ACT Science tutoring in New York, ACT Science tutoring in Chicago, or ACT Science tutoring in Los Angeles, working one-on-one with an expert may be just the boost your studies need.
That’s a lot of material to test. Because of just how much material there is, many students can feel lost about where to start. You may look at the sections included on the test, and panic when you see Science listed . . . especially if you are one of the many students who struggled in some of their high school science courses! Will you have to answer questions about that frog dissection from two years ago? Will you need to identify rocks from your Earth Science class? That might as well have been a lifetime ago.
Hopefully it calms your nerves a little bit to recognize that none of these things will be directly tested. You won’t have to dig up the details of your classes from several years back, nor will you be facing questions about advanced quantum physics or rocket science. Varsity Tutors offers resources like a free ACT prep book to help with your self-paced study, or you may want to consider an ACT Science tutor.
The ACT Science exam tests exactly what the rest of the ACT tests: your ability to think critically, analyze provided material, and draw inferences. It is far more a reading comprehension test, in fact, than a science test. It just so happens that you will be asked to comprehend passages based on science, which makes some students immediately anxious. This anxiety, unfortunately, does not set a good foundation for success on the exam!
Clearly, familiarizing yourself with the ACT Science exam before your actual test day is critical. Appreciating the exam for what it is, is critical. You may want to consider working with tutors, teachers, or in a test-preparation program to help you overcome the anxiety many students feel, and appreciate that your success on this exam is based on the same principles that you would need to succeed on any reading comprehension test.
It’s also important to consider that the time you spend on improving your performance on the ACT Science test doesn’t just pay off on test day. Precisely because the test is asking you to draw inferences, make conclusions, and think critically, you are developing skills that will be demanded in a wide variety of later academic pursuits. The time you spend preparing for the ACT Science exam can be thought of as a broad investment in your future performance across many disciplines.
Without a doubt, proper preparation for the ACT Science exam is essential. Overcoming anxiety is probably the first step. Varsity Tutors’ free ACT Science resources, and specifically our free ACT Science question of the day, can help you take the next step of making studying for your exam a habit. Our daily featured ACT Science problem provides the correct answer and a full explanation when answered; if you get it right, you gain confidence in your abilities, and if you get it wrong, you have the opportunity to fine-tune your understanding. In addition to the ACT Science Question of the Day and ACT Science tutoring, you may also want to consider taking some of our ACT Science practice tests. With practice questions, strategy, and proper perspective, you can achieve a great score and be well on your way to your dream college!
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