Hot Wheels of Glory (An Acceleration Lab)

Transcription

1 Hot Wheels of Glory (An Acceleration Lab) Background: In this lab you are going to investigate the relationship between time and how far an accelerating object travels? For example, will an accelerating object travel take twice as long to travel twice as far? Will it take three times as long to travel three times as far? To find out you will allow a hot wheels car, starting from rest, to roll down a ramp in this case a table propped up by two or three books. You will measure the time it takes for the car to go from the top of the ramp 25 cm, then the time it takes to go 50 cm, 75 cm, 100 cm, and 125 cm. You will take the average of at least three trials at each distance. After making a neat, properly labeled data table and collecting all data, you will make a proper, full-page graph of distance traveled vs. time it took. Distance will go on the y-axis and time on the x-axis. Be sure to include (0,0) as a data point. You will then use your graph to write a conclusion in which you summarize your purpose, hypothesis, results and technique answer the basic question posed by this lab. The force of gravity pulling on the car is constant 1

2 Hot Wheels of Glory (An Acceleration Lab) Background: Acceleration = Any change in velocity. Unbalanced forces cause acceleration. A constant unbalanced force will cause constant acceleration. On Earth s surface, gravity is a constant force. THREE POSSIBLE GRAPHICAL RELATIONSHIPS (COPY ALL): Direct It will take twice the time to go twice the distance. Straight line on a graph Exponential Decay It will take less than twice the time to go twice the distance. It will take more than twice the time to go twice the distance. Ever steepening line on a graph. Ever flattening line on a graph. Purpose: What is the relationship between time and distance for an object accelerated by a constant force? Prediction: Make a prediction that answers the question in the purpose. Write your prediction in words and sketch the shape you predict for the D-T graph. 2

3 Materials: Table (RAMP) 4-6 of the same book Masking tape Stopwatch Hot Wheels Car Meter Stick Tips and Tricks: Cars! o Treat them as if they were a fine piece of scientific equipment Books: Probably stack three high Data: Create a data table capable of holding all the data described in the introductory paragraph. Distance (cm) Time (seconds) Trial 1 Trial 2 Trial 3 Average

4 Hand Graph: Hot Wheels of Glory Post Lab Create a distance vs time graph of your data on the top half of a piece of graph paper. On the bottom half create a distance vs. time graph of the ideal data (Mr. Rundell s). Put time on the x-axis and distance on the y-axis. IDEAL DATA: Questions Distance (cm): Time (s) ) How far did the Hot Wheels car go in 1.0 s? 2) How far did the Hot Wheels car go in 2.0 s? 3) As time is doubled, what happens to distance (doubles, more than doubles, less than doubles)? 4) How many times farther did it go in 2.0 s compared to 1.0 s? Divide the distance travelled in 2.0 s by the distance travelled in 1.0 s to get your answer. 5) Describe the shape of the graph of distance vs time (D-T graph). 6) Why does this graph have the shape it does. 7) Compare the D-T graph of your own data to the D-T graph of the ideal data. Describe how they similar and how they are different. 8) Explain (give reasons) why your own graph and the ideal graph may look quite different. Conclusion: Write a conclusion in which you summarize your purpose, hypothesis, results, technique and answer the basic question posed by this lab. Support your answer with specific data from the lab. Refer to your reference on conclusion writing. Below is a short version. Write one paragraph for each number. 1. Restate Lab PURPOSE and PREDICTION (or Hypothesis): Prediction or hypothesis exactly matches the lab purpose meaning it uses the same variables. 2. Exactly describe the PROCEDURE (what you did). What are the independent and dependent variables? 3. State if the DATA do or do not support your prediction/hypothesis. Explain what the data show or mean. Cite examples (real numbers, graph slopes, etc.) 4. Explain SOURCES OF ERROR. Describe uncontrolled CONSTANTS and how data is affected. State opinion if data is still valid. Details support opinion. 5. Compare lab to a real world example and/or suggest a logical new experiment. Explain why your choice is important, interesting or relevant. 4

5 Conclusion Rubric: (attach to conclusion, turn in) Detail missing Some detail Complete detail 1 Restate Lab PURPOSE and PREDICTION (or Hypothesis): Prediction or hypothesis exactly matches the lab purpose meaning it uses the same variables. Conclusion Exactly describe the PROCEDURE (what you did). What are the independent and dependent variables? State if the DATA do or do not support your prediction/hypothesis. Explain what the data show or mean. Cite examples (real numbers, graph slopes, etc.) Explain SOURCES OF ERROR. Describe uncontrolled CONSTANTS and how data is affected. State opinion if data is still valid. Details support opinion. 5 Compare lab to a real world example and/or suggest a logical new experiment. Explain why your choice is important, interesting or relevant. 5