  Finding Speed with Finch

Measure how far the Finch goes in a predetermined amount of time and calculate its speed.

BEGINNER: Outputs Only

Required Lessons: Controlling Wheels, Pen Mount and Plastic Brick Adapter

Measure how far the Finch goes in 2 seconds at three different speeds. Then use the distance and time to find the speed of the Finch in centimeters per second.

Measurement procedure:

1. Place a marker in your Finch.
2. Create three programs that use the Finch Wheels block to move the Finch at three different speeds. Both wheels should be set to the same speed so that the Finch moves in a straight line.
• Program 1: Move the Finch forward for 2 seconds at 10%.
• Program 2: Move the Finch forward for 2 seconds at 50%.
• Program 3: Move the Finch forward for 2 seconds at 90%.
3. Run Program 1. Then pick up the Finch and measure the length of the line it drew in centimeters. Then repeat for Program 2 and Program 3. Record your data in the Table below. Calculating the Finch’s speed:

1. You calculate speed by dividing the distance something moved by the time that it moved. Calculate the speed of the Finch at 10% by dividing the distance for Program 1 by 2 seconds, the time that the Finch moved. This is the speed of the Finch in centimeters per second (cm/s). 2. Calculate the speed of the Finch at 50% and 90%.

Required Lessons: Encoders

Measure how far the Finch goes in 2 seconds at three different speeds, and use encoders to find out how far your Finch traveled. Then use the distance and time to find the speed of the Finch in meters per second.

Measurement procedure:

1. Create three programs that use the Finch Wheels block to move the Finch at three different speeds – 10%, 50%, or 90%. Each program should do the following:
• Reset the encoders before the Finch begins moving.
• Move the Finch at the given speed (10%, 50%, or 90%) for 2 seconds.
• The Finch wheel moves 15.7 cm in one rotation. Calculate the distance traveled in centimeters by multiplying the value of the right encoder by 15.7.
• You calculate speed by dividing the distance something moved by the time that it moved. Calculate the speed of the Finch by dividing the distance traveled by 2 seconds, the time that the Finch moved. This is the speed of the Finch in centimeters per second (m/s). • Display the speed of the Finch.
• Run your three programs. Record your data in the Table below.
• Convert each of your speeds from centimeters per second to meters per second. Remember, a meter contains 100 centimeters. MATERIALS

Beginner:

• Lay down butcher paper, large poster paper, or similar on the table or floor.
• Use washable markers for easy cleanup.

INTEGRATION

This activity fits well with math concepts involving measurement, unit conversion, and rates. It can also lead to fun extension questions, such as:

• How far would it take Finch to go from the classroom to their home? (Use Google maps to determine how far away students live from the classroom, and use their calculations.)
• Based on what you know, how fast do you expect the Finch to go at 70% speed (halfway between 50 and 90)?
• How fast is the Finch traveling in meters per sec (Beginner)?
• How fast is the Finch traveling in kilometers per hour or miles per hour (Intermediate)?
• How long would the Finch take to drive to the moon, 384,400 kilometers away, at 50% speed?