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AP Physics 1 Labs

4 min readnovember 15, 2021

Peter Apps

Peter Apps

Peter Apps

Peter Apps

AP Physics 1 Labs

Unlike some other courses you may have taken, there are no required labs for AP Physics 1. However, since there is an on every exam (except 2020), knowing how to properly perform a laboratory experiment is vital to your success in the course. The CollegeBoard expects about 25% of your class time do be done performing some sort of lab activities, and colleges may request to see evidence of this before accepting your AP credit.


What to Expect in a Lab Activity

In general, a lab activity should help you in one of the following ways:

  1. Help you gain understanding about a physics concept

  2. Help you design an experiment to minimize uncertainty and errors

  3. Help you interpret data (probably thorough graphical relationships)

  4. Help you derive and test a relationship between two variables.

  5. Help you prep for the

Ideally every lab should cover all of these areas, but just in case they don't, let's walk through some common things you should be able to do after doing several labs.


Design an Experiment to Minimize Errors

This is a key component of the . In any given experiment, you'll have to deal with 3 main types of errors: Experimental, Systematic, and Random.

Experimental errors are errors that occur through mistakes that are made by you conducting the experiment. A great example of these are timing errors made by using a stopwatch. Your reaction time is included in all of these time measurements and gives a reading that is not accurate. It's not the fault of the stopwatch, or the design of the experiment, but rather simply an artifact of a human using that tool.

https://d1wfu1xu79s6d2.cloudfront.net/wp-content/uploads/2014/02/LR4-fig-1-Accurate-results-are-achieved-by-improving-both-precision-and-trueness.png

Image Courtesy of Artel.co

Systematic errors are errors that occur due to the equipment itself. For example, a may not be zeroed before you use it, or you may have zeroed it while holding it vertically but plan on using it horizontally. These errors can often be corrected for if you know about them in advance, but are difficult to correct for after the experiment is already completed. Systematic errors affect the accuracy of the experiment, but not necessarily the precision of the measurements.

Random errors are, well, random. These are errors that occur completely outside of your control. Temperature variations in a classroom, wind blowing during an outside lab, and changing friction between an object and the ground can all be random errors.

In all these cases, the best way to try to minimize these errors is by doing multiple trials. Design your experiment so that every key measurement is taken several times so that an average can be found. Averaging helps reduce random errors and experimental errors such as reaction time.

In addition using tools with less uncertainty in their measurements can help reduce these errors as well. For example, using a pair of will give a more precise time than a stopwatch, because we have removed our reaction times from the experiment. Likewise, using a instead of a ruler and stopwatch to measure velocity can yield better results. Other examples of this could include using a instead of a ruler, a instead of a spring scale, and a instead of a triple beam one.

If you're looking for more information on this, check out the College Board's Data Analysis Guide, or Fiveable's Live Stream Reviews covering Uncertainty.


Interpreting and Graphing Data

As I'm sure you're aware of by now, graphing is a wonderful way of determining and verifying relationships between variables in an experiment. A good graph can also help you identify outliers and sources of systemic errors. When you're making a graph, there are a few things to keep in mind:

  1. Label each axis with the variable that is plotted on it and its units

  2. Scale each axis with a reasonable number of labeled tick marks at even intervals. Make sure your chosen scale doesn't cramp the data to only one section of the graph, but spreads it out so that patterns can be seen.

  3. Plot your independent variable on the x-axis (the one that isn't changed by the other variables you're trying to measure). Most often, this is time or distance

  4. Plot your dependent variable on the y-axis.


Plotting a Linear Graph from Non-Linear Data

A is the most useful for helping us verify expectations and determine relationships. It also happens to be the simplest type of graph (y=mx+b). This lets us determine the (which often is an important physical quantity, like acceleration from a velocity vs time graph or the spring constant from a Force vs distance graph). We can also easily see if the is 0, which can be useful to help diagnose experimental and systematic errors.

However many times, the relationship we're trying to graph isn't linear. A great example of this is when we're looking at the displacement of an object with a constant acceleration. Simply plotting x vs t gives us a graph like this.

https://firebasestorage.googleapis.com/v0/b/fiveable-92889.appspot.com/o/images%2Fchart.png?alt=media&token=aa21cb21-c41d-4feb-96cc-53c9b9ede32e

Looking at the graph, we can see that this relationship looks like it's quadratic.

https://bitpaper.s3-eu-west-1.amazonaws.com/8808173904.png

This means that since the general formula for a quadratic is y=ax^2+bx+c, to make a we need to plot y vs x^2. Once we make that change, the graph becomes linear, and we can find the and .

https://firebasestorage.googleapis.com/v0/b/fiveable-92889.appspot.com/o/images%2Fchart%20(1).png?alt=media&token=4c06427c-e1e5-47c2-adbd-eb2e3ae0de9d

Alternatively we could have graphed sqrt(Displacement) vs time and gotten a , but I think it's always easier to square rather than square-root.

Other common scenarios involve plotting:

  • y = 1/x for inverse plots

  • log(y) = log(x) for exponential plots.

🎥Watch: AP Physics 1 - Graphing and Interpreting Graphs

Key Terms to Review (10)

Digital Balance

: A digital balance is a measuring instrument used to determine the mass or weight of an object with high precision. It provides digital readouts for easy and accurate measurements.

Digital Caliper

: A digital caliper is a measuring tool used to accurately determine the dimensions (lengths, widths) of small objects with high precision. It consists of two jaws that can be adjusted and provide measurements displayed digitally on a screen.

Experimental Design FRQ

: The Experimental Design Free Response Question (FRQ) is a type of question in the AP Physics 1 exam that assesses students' ability to design and plan an experiment to investigate a given phenomenon. It requires students to identify variables, control factors, and outline procedures.

Force Sensor

: A force sensor is a device that measures the amount of force applied to it. It converts the physical force into an electrical signal that can be measured and analyzed.

Linear Graph

: A linear graph is a graphical representation of data that shows a straight-line relationship between two variables. It indicates that as one variable increases, the other variable changes at a constant rate.

Motion Sensor

: A motion sensor is a device that detects movement or changes in position by emitting and receiving signals such as ultrasound or infrared waves. In physics experiments, motion sensors are often used to collect data on the position, velocity, and acceleration of objects.

Photo-gates

: Photo-gates are devices that use infrared light beams to detect the presence or absence of an object passing through them. They are commonly used in physics experiments to measure time intervals and calculate velocities.

Quadratic relationship

: A quadratic relationship is a mathematical relationship between two variables that can be represented by a quadratic equation, where the variable is raised to the power of 2.

Slope

: Slope refers to the steepness or incline of a line on a graph. It represents how much one variable changes with respect to another variable.

Y-intercept

: The y-intercept is the point where a line crosses or intersects the y-axis on a graph.

AP Physics 1 Labs

4 min readnovember 15, 2021

Peter Apps

Peter Apps

Peter Apps

Peter Apps

AP Physics 1 Labs

Unlike some other courses you may have taken, there are no required labs for AP Physics 1. However, since there is an on every exam (except 2020), knowing how to properly perform a laboratory experiment is vital to your success in the course. The CollegeBoard expects about 25% of your class time do be done performing some sort of lab activities, and colleges may request to see evidence of this before accepting your AP credit.


What to Expect in a Lab Activity

In general, a lab activity should help you in one of the following ways:

  1. Help you gain understanding about a physics concept

  2. Help you design an experiment to minimize uncertainty and errors

  3. Help you interpret data (probably thorough graphical relationships)

  4. Help you derive and test a relationship between two variables.

  5. Help you prep for the

Ideally every lab should cover all of these areas, but just in case they don't, let's walk through some common things you should be able to do after doing several labs.


Design an Experiment to Minimize Errors

This is a key component of the . In any given experiment, you'll have to deal with 3 main types of errors: Experimental, Systematic, and Random.

Experimental errors are errors that occur through mistakes that are made by you conducting the experiment. A great example of these are timing errors made by using a stopwatch. Your reaction time is included in all of these time measurements and gives a reading that is not accurate. It's not the fault of the stopwatch, or the design of the experiment, but rather simply an artifact of a human using that tool.

https://d1wfu1xu79s6d2.cloudfront.net/wp-content/uploads/2014/02/LR4-fig-1-Accurate-results-are-achieved-by-improving-both-precision-and-trueness.png

Image Courtesy of Artel.co

Systematic errors are errors that occur due to the equipment itself. For example, a may not be zeroed before you use it, or you may have zeroed it while holding it vertically but plan on using it horizontally. These errors can often be corrected for if you know about them in advance, but are difficult to correct for after the experiment is already completed. Systematic errors affect the accuracy of the experiment, but not necessarily the precision of the measurements.

Random errors are, well, random. These are errors that occur completely outside of your control. Temperature variations in a classroom, wind blowing during an outside lab, and changing friction between an object and the ground can all be random errors.

In all these cases, the best way to try to minimize these errors is by doing multiple trials. Design your experiment so that every key measurement is taken several times so that an average can be found. Averaging helps reduce random errors and experimental errors such as reaction time.

In addition using tools with less uncertainty in their measurements can help reduce these errors as well. For example, using a pair of will give a more precise time than a stopwatch, because we have removed our reaction times from the experiment. Likewise, using a instead of a ruler and stopwatch to measure velocity can yield better results. Other examples of this could include using a instead of a ruler, a instead of a spring scale, and a instead of a triple beam one.

If you're looking for more information on this, check out the College Board's Data Analysis Guide, or Fiveable's Live Stream Reviews covering Uncertainty.


Interpreting and Graphing Data

As I'm sure you're aware of by now, graphing is a wonderful way of determining and verifying relationships between variables in an experiment. A good graph can also help you identify outliers and sources of systemic errors. When you're making a graph, there are a few things to keep in mind:

  1. Label each axis with the variable that is plotted on it and its units

  2. Scale each axis with a reasonable number of labeled tick marks at even intervals. Make sure your chosen scale doesn't cramp the data to only one section of the graph, but spreads it out so that patterns can be seen.

  3. Plot your independent variable on the x-axis (the one that isn't changed by the other variables you're trying to measure). Most often, this is time or distance

  4. Plot your dependent variable on the y-axis.


Plotting a Linear Graph from Non-Linear Data

A is the most useful for helping us verify expectations and determine relationships. It also happens to be the simplest type of graph (y=mx+b). This lets us determine the (which often is an important physical quantity, like acceleration from a velocity vs time graph or the spring constant from a Force vs distance graph). We can also easily see if the is 0, which can be useful to help diagnose experimental and systematic errors.

However many times, the relationship we're trying to graph isn't linear. A great example of this is when we're looking at the displacement of an object with a constant acceleration. Simply plotting x vs t gives us a graph like this.

https://firebasestorage.googleapis.com/v0/b/fiveable-92889.appspot.com/o/images%2Fchart.png?alt=media&token=aa21cb21-c41d-4feb-96cc-53c9b9ede32e

Looking at the graph, we can see that this relationship looks like it's quadratic.

https://bitpaper.s3-eu-west-1.amazonaws.com/8808173904.png

This means that since the general formula for a quadratic is y=ax^2+bx+c, to make a we need to plot y vs x^2. Once we make that change, the graph becomes linear, and we can find the and .

https://firebasestorage.googleapis.com/v0/b/fiveable-92889.appspot.com/o/images%2Fchart%20(1).png?alt=media&token=4c06427c-e1e5-47c2-adbd-eb2e3ae0de9d

Alternatively we could have graphed sqrt(Displacement) vs time and gotten a , but I think it's always easier to square rather than square-root.

Other common scenarios involve plotting:

  • y = 1/x for inverse plots

  • log(y) = log(x) for exponential plots.

🎥Watch: AP Physics 1 - Graphing and Interpreting Graphs

Key Terms to Review (10)

Digital Balance

: A digital balance is a measuring instrument used to determine the mass or weight of an object with high precision. It provides digital readouts for easy and accurate measurements.

Digital Caliper

: A digital caliper is a measuring tool used to accurately determine the dimensions (lengths, widths) of small objects with high precision. It consists of two jaws that can be adjusted and provide measurements displayed digitally on a screen.

Experimental Design FRQ

: The Experimental Design Free Response Question (FRQ) is a type of question in the AP Physics 1 exam that assesses students' ability to design and plan an experiment to investigate a given phenomenon. It requires students to identify variables, control factors, and outline procedures.

Force Sensor

: A force sensor is a device that measures the amount of force applied to it. It converts the physical force into an electrical signal that can be measured and analyzed.

Linear Graph

: A linear graph is a graphical representation of data that shows a straight-line relationship between two variables. It indicates that as one variable increases, the other variable changes at a constant rate.

Motion Sensor

: A motion sensor is a device that detects movement or changes in position by emitting and receiving signals such as ultrasound or infrared waves. In physics experiments, motion sensors are often used to collect data on the position, velocity, and acceleration of objects.

Photo-gates

: Photo-gates are devices that use infrared light beams to detect the presence or absence of an object passing through them. They are commonly used in physics experiments to measure time intervals and calculate velocities.

Quadratic relationship

: A quadratic relationship is a mathematical relationship between two variables that can be represented by a quadratic equation, where the variable is raised to the power of 2.

Slope

: Slope refers to the steepness or incline of a line on a graph. It represents how much one variable changes with respect to another variable.

Y-intercept

: The y-intercept is the point where a line crosses or intersects the y-axis on a graph.


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AP® and SAT® are trademarks registered by the College Board, which is not affiliated with, and does not endorse this website.


© 2024 Fiveable Inc. All rights reserved.

AP® and SAT® are trademarks registered by the College Board, which is not affiliated with, and does not endorse this website.