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