Post on 18-Jan-2016
74 Measuring Speed
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74 Measuring Speed
Key Vocabulary
• distance• evidence• error• controlled variable• rate• speed• tested variable• time interval
• variable
74 Measuring Speed
What things can contribute to a car accident?
Record your answer in your notebook.
74 Measuring Speed
How do you think speed is measured?
Share your ideas with the class.
74 Measuring Speed
How did people measure speed before technological devices were invented?
Share your ideas with the class.
74 Measuring Speed
Read the introduction and look for key ideas
This car speedometer shows speed in miles per hour and in kilometers per hour. Kilometers per hour is the
speed unit commonly used in other countries.
74 Measuring Speed
How can you measure the speed of a moving cart?
74 Measuring Speed
Review the procedure
Why do you think you are asked to do three trials?
74 Measuring Speed
Potential errors
74 Measuring Speed
Complete procedure part A
speed = distance/time
What is the speed of a car that travels 100 miles in 2 hours?
What is the speed of a car that travels 30 kilometers in ½ hour?
74 Measuring Speed
Class results for cart speed
74 Measuring Speed
Complete procedure part B
SCORING GUIDE: Designing Investigations
74 Measuring Speed
Experimental design
74 Measuring Speed
Analysis question 1
According to your data from Part A, what is the speed of the cart?
74 Measuring Speed
Analysis question 2
According to your data from Part B, what is the effect of release height on speed?
74 Measuring Speed
Analysis question 3
List some common units for speed. Why are there so many different units?
74 Measuring Speed
What unit would be most convenient to measure how fast your fingernails grow?
Share your thoughts with the class.
74 Measuring Speed
Analysis question 4
What part(s) of your experimental design in Part B:
a. increased your confidence in the results?
b. decreased your confidence in the results?
74 Measuring Speed
Analysis question 5
What is a car’s speed in m/s if it travels:
a. 5 meters in 0.1 seconds?
b. 5 meters in 0.2 seconds?
c. 10 meters in 0.2 seconds?
74 Measuring Speed
Analysis question 6
Reflection: Why do you think speeding is a factor in about 20% of fatal car accidents?
74 Measuring Speed
What is a rate?
Brainstorm examples of rates and describe two measurements needed to determine the rate.
Share your answers with the class.
74 Measuring Speed
How can you measure the speed of a moving cart?
74 Measuring Speed
Key vocabulary definitions
Distance - The length measured between two points.
Evidence - Factual information or data that supports or refutes a claim.
74 Measuring Speed
Key vocabulary definitions
Error - Unavoidable variation between a measurement and the true value of a quantity that occurs when measurements cannot be made with greater accuracy.
Controlled variable - A variable in an investigation or experiment that is held constant.
74 Measuring Speed
Key vocabulary definitions
Rate - A ratio of two different kinds of measurements. Speed, the ratio of distance to time, is an example.
Speed - The rate at which an object moves, equal to the distance traveled per time interval.
74 Measuring Speed
Key vocabulary definitions
Tested variable - A variable that is changed in a systematic way in an experiment or investigation in order to determine its effect.
Time interval - The time between two events.
Variable - A factor in a scientific experiment that can vary.
74 Measuring Speed
Compare results
Post your results on the Issues and Physical Science page of the SEPUP website, and compare your data set to that of students in other classes.
www.sepuplhs.org
74 Measuring Speed
Calculate
If the speed limit is 60 MPH, could the police give a speeding ticket to any of the drivers of the cars in Analysis Question 5?
Hint: 1,000 m = 1 km = 0.62 miles