Analysis
ChatGPT’s consistent incorrect responses may result in students receiving incorrect or confusing information when using ChatGPT as a learning tool for physics or chemistry. The following sections discuss the potential causes and implications of ChatGPT’s incorrect responses, and how educators can adapt to widespread student use of ChatGPT with these limitations in mind.
In some cases, ChatGPT’s responses to inventory questions represent accurate theoretical understanding of concepts in physics and chemistry, and its explanations may be helpful to students. For example, when asked to compare the collision forces between a large truck and small compact car, ChatGPT explains,
According to Newton’s Third Law of Motion, for every action, there is an equal and opposite reaction. Therefore, during the collision between the truck and the car, both vehicles will exert equal and opposite forces on each other. The truck exerts the same amount of force on the car as the car exerts on the truck.
In other cases, though, ChatGPT responses are likely to mislead learners. For example, ChatGPT’s responses to kinematics questions reflected common student difficulties distinguishing velocity and acceleration, as well as a tendency to add velocities as scalars rather than vectors[11]. When asked about a constant-velocity hockey puck that receives a horizontal “kick” in the direction horizontally perpendicular to its existing path, ChatGPT explained,
Since the surface is frictionless, the horizontal component of the velocity of the puck should remain constant throughout its motion. Therefore, the speed of the puck just after it receives the kick should be the arithmetic sum of the speed it had before the kick and the speed it acquires from the kick. Thus, the answer is the arithmetic sum of speeds v0 and v.
In another response to the hockey puck scenario, ChatGPT interpreted the instantaneous horizontal “kick” to be a long-lasting force that produces circular motion:
When the hockey puck receives an instantaneous horizontal “kick” in the direction horizontally perpendicular to its existing path at point B, it will start to move in a curved path. Since the surface is frictionless, there is no force to slow down or stop the puck’s motion. The puck will continue moving with a constant speed but changing direction due to the force acting on it.
Frequently, ChatGPT’s responses would describe the associated concept necessary for solving the question correctly, but apply the concept incorrectly. For example, when responding to a question about a sample of water with sugar dissolved in it, ChatGPT explained:
When a solute like sugar is dissolved in a solvent like water, the molecules of the solute become evenly dispersed throughout the solution. If more solvent is added to the solution, the concentration of the solute decreases, but the number of solute molecules in the solution remains the same. Therefore, when additional water is added to the solution, the number of sugar molecules in the 0.5 L sample taken from the same height (0.5 L line) will be the same as before.
In the above situation, ChatGPT’s explanation of concentration in solution is accurate, but it fails in correctly interpreting the applied context of taking a sample of a solution. Similarly, in a response to a question about water evaporating in a closed container, it treated the system as open:
When all the water in a closed container is evaporated, the area that was previously filled with water molecules will be empty, and there will be no molecules in that area… If the area is viewed under a microscope, it will appear empty because there are no molecules present to reflect or scatter light.
Occasionally, ChatGPT may misinterpret the ‘archetype’ of questions, causing incorrect responses that would be correct if the context were different. For example, in response to a question about a rocket engine firing with constant thrust at a right angle to the rocket’s initial motion, ChatGPT incorrectly states that the rocket’s speed is constant during the thrust:
As the rocket’s engine produces a constant thrust at a right angle to the line [of initial motion], the rocket will move in a circular path... Therefore, the rocket’s speed will be constant, as it moves with a constant angular velocity.
This response, however, would be correct if the rocket were using its thrust to maintain orbit around a planet, another common type of question associated with rockets. Sometimes, ChatGPT’s interpretations veer toward the surreal: in a question regarding a ball on a string that a person swings in a horizontal circle over their head, ChatGPT responds,
According to Newton’s First Law of Motion, an object in motion will continue in a straight line with a constant speed unless acted upon by a net external force. In this case, the heavy ball is moving in a circular path due to the tension force in the string, which provides the necessary centripetal force. When the string suddenly breaks, there is no longer a centripetal force acting on the ball, and it will continue to move tangentially to its path at the moment of release. However, since the person is also moving in the circular path, the ball will also have a component of motion towards the person. Therefore, the path the ball will travel relative to the person is mostly tangential to its path at the moment of release, but curved inwards along the horizontal plane towards the person.
The AI may again be interpreting the language of the prompt as similar enough to another archetype of question- in this case, misinterpreting a question about horizontal centripetal force as a question about orbits- to attempt to answer the prompt as if it were responding to the other archetype.
Overall, ChatGPT is an unreliable source of physics and chemistry reasoning. It frequently misinterprets the context, content, and constraints of questions.
