Energy in Motion

D. Pushing and pulling the front coil of a metal spring/slinky LONGITUDINAL

Part 4: Wave Speed Formula Worked Solutions (4 Points)

Equation: \( v = f \times \lambda \)

Problem A: Ocean Swell 2 pts (1 work, 1 ans)

Given: \(\lambda = 8\text{ m},\; f = 0.5\text{ Hz}\)

Formula: \(v = f \times \lambda\)

Work: \(v = 0.5\text{ s}^{-1} \times 8\text{ m} = 4\text{ m/s}\)

✔ Final Answer: 4 m/s (or 4 meters per second)

Problem B: Sound Wave 2 pts (1 work, 1 ans)

Given: \(v = 340\text{ m/s},\; f = 170\text{ Hz}\)

Formula: \(\lambda = \frac{v}{f}\)

Work: \(\lambda = \frac{340}{170} = 2\text{ meters}\)

✔ Final Answer: 2 m (or 2 meters)

Part 5: "Consider the Following" Rubric & Exemplar (4 Points)

4-Point Rubric

Exemplar Student Response:
"The duck bobs up and down because waves transfer energy across the ocean, not the physical water. The water molecules move in a circular or oscillating path and return to where they started. Since the water itself is not flowing forward across the sea, the floating duck stays in the same general spot while the wave energy travels past."

✔ 1 pt: States waves transfer energy, not matter.

✔ 1 pt: Explains water particles oscillate/bob in place.

✔ 1 pt: Connects water motion directly to duck's movement.

✔ 1 pt: Clear complete sentences using science terms.

Part 6: Exit Ticket Acceptable Key Ideas (2 Points): Any 1 Core Theme

• Energy Transfer: "Waves carry energy from place to place without permanently moving matter."
• Wave Dualism: "Transverse waves move perpendicular to energy, while longitudinal waves move through compressions."
• Universal Law: "All waves have frequency, wavelength, and speed tied by the formula \(v = f \times \lambda\)."

Bill Nye the Science Guy • "Waves" Teacher Answer Key Page 2 of 3 • See Page 3 for Word Search Master Key

Word Search Master Key (30 Terms)

Highlighted solution grid and row-by-row word coordinates

10 Points Total

W A V E L E N G T H K Z R A D I O P

B L O N G I T U D I N A L L I G H T

C O M P R E S S I O N B J H E R T Z

T R A N S V E R S E F Q P C R E S T

R A R E F A C T I O N T R O U G H X

O S C I L L A T I O N U E N E R G Y

D I F F R A C T I O N C G S O U N D

R E F L E C T I O N D Y M A T T E R

R E F R A C T I O N P V M E D I U M

F R E Q U E N C Y J H S E I S M I C

A M P L I T U D E L W T S U N A M I

V I B R A T I O N X V E L O C I T Y

S P E C T R U M K T Z B I L L N Y E

E C H O G N P J K M Q W Z P I T C H

P E R I O D Z K W A V E S F B N Q X

Row 0: WAVELENGTH, RADIO

Row 1: LONGITUDINAL, LIGHT

Row 2: COMPRESSION, HERTZ

Row 3: TRANSVERSE, CREST

Row 4: RAREFACTION, TROUGH

Row 5: OSCILLATION, ENERGY

Row 6: DIFFRACTION, SOUND

Row 7: REFLECTION, MATTER

Row 8: REFRACTION, MEDIUM

Row 9: FREQUENCY, SEISMIC

Row 10: AMPLITUDE, TSUNAMI

Row 11: VIBRATION, VELOCITY

Row 12: SPECTRUM, BILL NYE

Row 13: ECHO, PITCH

Row 14: PERIOD, WAVES

Vocabulary Link Challenge Exemplars (2 Points):

• "A vocal cord creates a vibration that travels as a sound wave through the air medium to your ear."

• "The wave transfers energy through rapid air particle compression and rarefaction cycles."

Bill Nye the Science Guy • "Waves" Teacher Answer Key Page 3 of 3 • End of Key