//code.Node Cart Wheels: Diameter and Distance



//code.Node Cart Wheels: Diameter and DistanceHow can you calculate the circumference of a //code.Node Cart wheel and use it to determine distance traveled?Objectives Investigate and determine how the cart uses the magnetic field sensor to determine position.Know and utilize the formula for the circumference of a circle and use it to solve problems. Refine computational models based on the data they have generated. Materials and EquipmentData collection system//code.Node//code.Node CartMeasuring tapetape SafetyFollow your normal classroom procedures. ProcedurePart 1 – Determining your cart's wheel circumferenceThe circumference of a circle is the total distance around its outside. Circumference equals the diameter of the circle times π (pi), which is about 3.14. One rotation of a wheel will make it move a distance equal to its circumference. 1.Using a measuring tool, determine the diameter of one of your cart's wheels. Try to get it to the nearest millimeter (mm). 2.Convert that measurement to meters (m). 3.Using this number, determine the circumference of your wheel. (Diameter X 3.14) Record your answer so you can refer to it later. ___________Part 2 – Using circumference to determine distanceExample: If the wheel below has a diameter of 50 mm and completes 2.3 rotations, how far will it go in meters? Diameter = 50 mmConvert to meters = .05 m Next multiply 3.14 x .05 = .157 mNext multiply .157 m x 2.3 rotations = .36 meters1.Using the circumference you calculated for the cart's wheel in Part 1, how far would it travel in meters after 8 rotations? Show your work. Part 3 – Investigating the Magnetic Field SensorWith the //code.Node removed from the cart, examine the rear axle of the cart when you spin the wheels. What do you see when you spin the tires? Believe it or not, that is a bar magnet. This magnet works with the magnetic field sensor within the //code.Node. A 180? turn of the wheel is a half rotation and is measured in either positive or negative Gauss (G). Another 180? turn completed a full rotation. You can measure the number of rotations of the wheel using a graph of magnetic field strength vs. time.1.Place your //code.Node into the cart and turn it on.2.Select Sensor Data in SPARKvue and connect your sensor to your device.3.Select Magnetic Field Sensor and disable all other sensors for the //code.Node.4.Select the Line Graph Display and make sure you have a graph of Magnetic Field Strength versus Time.5.Use a measuring tape to create a .5 m long track. Mark the starting point at 0 and the end at .50 meters. See Figure 1.6.Using the live data bar on the bottom left-hand side of the SPARKvue screen, turn the rear wheel until the field strength reads as close to 0 G as possible. Mark this position with tape and an arrow as seen in Figure 1. This is your starting position. Figure 1: Live data bar and track set-up7.Place the cart with the front bumper on zero as shown in Figure 1 and Start collecting data.8.Move your cart to the .50 m line and then stop recording data. 9.Repeat steps 6 - 8 two more times. Be sure to place the arrow in the same starting position. You should now have three runs. Save the data file as Magnetic Field vs Time or according to your teacher's directions. 10.Do you see a pattern in your graph? How many peaks are visible? Talk to a partner about the data you observe. 11.Choose one of the runs and recreate this graph on Graph #1. Make sure to label the x and y - axes and create a scale. Can you determine the number of rotations completed by your cart in .50 m? Part 4 – Blockly Coding Challenge: Rotation Indicator1.Using the data you have collected in Part 3, create a program that will alert the user to every rotation of the wheel. Hint: Choose the magnetic field strength under hardware. 2.Once you have completed your program, share it with other classmates and compare solutions to the challenge. 3.Save your program as Rotation Counter or according to your teacher's directions. Part 5 – Blockly Coding Challenge: Wheels, diameter, and distance traveledYou have been able to calculate the circumference of the tires on your cart. Using this information, as well as your knowledge of how the cart calculates position, replicate the following program that will calculate the number of full rotations over a determined distance. 1.First you will need to create a mathematical expression using a Function block. Name the function "# of rotations". 2.Next create a variable and name it "full rotation". 3.Replicate the mathematical expression. You are telling the computer to take the total distance traveled by the cart and divide that number by the circumference of the wheel. Plug the circumference you calculated in Part 1 into the math block after the division sign. 4.Next you will create the program in which you will plug in the Function you created previously. Replicate the following program. 5.After you have replicated the program, click done and add a new page. Select the 2-page template . On the left choose the Line Graph Display and select the Magnetic Field Strength (G) measurement. On the right, choose the Digits display, select Measurement and then choose User-Entered and Rotation. This reflects the numerical output your created in your program. 6.Using the same track you created in Part 3, place your cart at the starting line. Start collecting data and push your cart across the table. Stop recording data and check your program for accuracy.7.Spend some time investigating this program by doing multiple trials or even increasing the distance of the track. 8.Challenge: If time allows, expand on this program so that the 5x5 LED array on the //code.Node displays the number of rotations along with the numerical output on the SPARKvue screen. Data CollectionGraph 1: Magnetic Field vs. TimeQuestions and Analysis1. Find the circumference of the circle. Show your work and round your answer to the nearest hundredth. C = 2πr Circumference _______________2.Find the circumference of the wheel and determine how far it would travel after 2.3 revolutions. Show your work and round your answer to the nearest hundredth. C = πdCircumference __________________Covert to meters ________________Distance traveled in meters after 2.3 rotations ____________3.In Part 3 you investigated the magnetic field sensor of the cart. Looking at your data, about how many times did the wheel complete a full rotation in .5 m? Explain your answer. 4.You have a toy robot that has wheels with a diameter of 6 cm. If you want the toy robot to move forward .75 m, how many rotations must the wheels make? Show your work. 5.In Part 3, why was it important to make sure your wheel was at the same position before you start collecting data? 6.In Part 4, you had to create a program that alerted the user to when the wheel completed a full rotation. Did you face any challenges here and if so, how did you overcome them?7.In Part 5 you replicated a program that would perform a calculation to tell you how many rotations your cart completed in a set distance. What was the circumference you plugged into the math block? Was your program successful and did you make any modifications? 8.The Repeat While Block repeats a single block or multiple blocks in a loop while or until a condition is true. What condition did you set for your program to run in Part 5? ................
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