Predict Wave Behavior - Middle School Physical Science

1. What happens to wave speed when a wave enters a material where it travels faster?

   Wave speed increases in the new material. Waves travel at different speeds in different materials based on their properties.

2. What happens to a transverse wave's speed on a string if the string's mass per length increases?

   Wave speed decreases. Heavier strings move more slowly, reducing wave propagation speed.

3. What happens to a light ray when it enters a material with a higher refractive index (slower speed)?

   It bends toward the normal. Slower speed in denser media bends light toward perpendicular.

4. What happens to the direction of a wave entering a slower medium at an angle?

   It bends toward the normal. Slower speed causes the wave to bend closer to perpendicular.

5. Which material generally lets sound travel slowest: a solid, liquid, or gas?

   A gas. Gas particles are far apart, making vibration transfer slowest.

6. Which property of a medium mainly determines the speed of sound: density or color?

   Density (and elasticity), not color. Sound speed depends on how tightly packed and elastic the material is.

7. What is transmission in terms of wave behavior at a boundary between materials?

   A wave passes into the new material. Some wave energy continues forward when hitting a boundary.

8. What happens to wavelength when a wave enters a material where its speed is higher?

   Wavelength increases. Since $v=f\lambda$ and $f$ is constant, faster $v$ means larger $\lambda$.

9. Which option best describes refraction: change in direction, change in frequency, or change in amplitude?

   Change in direction (bending) in a new material. Speed change at boundaries causes path deviation.

10. What is the normal line in a refraction diagram?

    A line perpendicular to the boundary surface. Used as reference for measuring angles of incidence and refraction.

11. What happens to a light ray when it enters a material with a lower refractive index (faster speed)?

    It bends away from the normal. Faster speed in less dense media bends light away from perpendicular.

12. What happens to wavelength when wave speed decreases but frequency stays constant?

    Wavelength decreases. Since $v = f\lambda$ and frequency is constant, wavelength must decrease with speed.

13. What happens to wavelength when a wave enters a material where its speed is lower?

    Wavelength decreases. Since $v=f\lambda$ and $f$ is constant, slower $v$ means smaller $\lambda$.

14. What is the main wave behavior called when a wave is reduced because energy is taken in by the material?

    Absorption. Materials convert wave energy to other forms like heat.

15. What happens to frequency when a wave enters a new material (new medium)?

    Frequency stays the same. The source determines frequency, not the medium.

16. What quantity usually changes when a wave enters a new material: speed, frequency, or both?

    Speed changes. Material properties affect wave propagation speed.

17. What happens to wave speed when the medium becomes denser (more mass per volume), all else equal?

    Wave speed decreases. More mass per volume means slower particle acceleration.

18. What is the main wave behavior called when a wave passes through a material with reduced amplitude?

    Transmission. Waves pass through but lose energy to the material.

19. What happens to the direction of a wave entering a faster medium at an angle?

    It bends away from the normal. Faster speed causes the wave to bend farther from perpendicular.

20. What is refraction in terms of wave behavior at a boundary between materials?

    Bending due to a change in wave speed. Waves bend when entering materials with different speeds.

21. What is the main wave behavior called when a wave bounces off a boundary between materials?

    Reflection. Waves bounce back when encountering material boundaries.

22. What happens to frequency when a wave crosses into a different material?

    Frequency stays the same. The source determines frequency, which doesn't change when crossing boundaries.

23. A wave has $f=10\ \text{Hz}$ and $v=20\ \text{m/s}$. What is $\lambda$ in that material?

    $\lambda=2\ \text{m}$. Using $\lambda=\frac{v}{f}=\frac{20}{10}=2$ m.

24. What happens to wavelength when wave speed increases but frequency stays constant?

    Wavelength increases. Since $v = f\lambda$ and frequency is constant, wavelength must increase with speed.

25. What is reflection in terms of wave behavior at a boundary between materials?

    A wave bounces back into the original medium. Some wave energy returns when hitting a boundary between materials.

26. Which material generally transmits sound faster: a solid, a liquid, or a gas?

    A solid. Particles are closer in solids, transmitting vibrations faster.

27. If a wave enters a new material and its speed halves, what happens to its wavelength (same $f$)?

    Wavelength halves. From $v=f\lambda$: if $v$ halves and $f$ stays constant, $\lambda$ halves.

28. What happens to a transverse wave's speed on a string if the tension increases?

    Wave speed increases. Higher tension makes the string return to position faster, increasing wave speed.

29. What is the relationship between wave speed, frequency, and wavelength: $v$, $f$, and $\lambda$?

    $v=f\lambda$. Wave speed equals frequency times wavelength.

30. Which material generally lets sound travel faster: a solid or a gas?

    A solid. Particles in solids are tightly packed, allowing faster vibration transfer.

31. Which wave property must change for refraction to occur at a boundary?

    Wave speed must change. Different speeds in different materials cause the wave to bend.

32. Which material generally transmits sound slowest: a solid, a liquid, or a gas?

    A gas. Particles are farther apart in gases, slowing sound transmission.

33. Identify the correct statement: higher absorption causes amplitude to increase or decrease?

    Amplitude decreases. Energy loss from absorption reduces wave height.

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