Science Waves Unit Part A 8th gr 24-25

The table shows an electromagnetic wave and a mechanical wave with their characteristics. Which best compares the difference between electromagnetic and mechanical waves?

• Electromagnetic waves are longitudinal, while mechanical waves are transverse.

• Electromagnetic waves can travel through a vacuum, while mechanical waves cannot.

• Mechanical waves can travel at the speed of light, while electromagnetic waves cannot.

• 
  Mechanical waves consist of electric and magnetic fields, while electromagnetic waves do not.

Answer explanation

Electromagnetic waves can travel in space without any medium, while mechanical waves need a medium to transport from one place to another.

Use the drop-down menu to complete the description of a wave.

A wave is transporting energy from left to right. The particles of the medium are moving back and forth in a leftward and rightward direction. This type of wave is known as​ (a)  

• Longitudinal
• Transverse
• Surface

Which question will help the student determine if the wave is electromagnetic or magnetic?

• Can it pass through air and water?

• Does it have a measurable speed?

• Does it require a medium to travel?

• Does it have a measurable frequency?

Answer explanation

An electromagnetic wave requires a medium to travel, so this would allow the student to determine an electromagnetic wave.

Which TWO properties are not present in mechanical waves?

• amplitude

• wavelength

• electric field

• compression

• magnetic field

Answer explanation

Mechanical waves do not have electric fields.

Mechanical waves do not have magnetic fields.

Which is NOT a mechanical wave?

• sound wave

• ocean waves

• seismic waves

• electromagnetic wave

A wave travels through the air. The particles of the wave move at right angles to the motion of the energy of the wave. What type of wave is this?

• light 

• sound

• longitudinal

• transverse

Answer explanation

In a transverse wave, the particles of the wave move at right angles to the motion of the energy of the wave.

Use the drop-down menus to complete the sentences describing crests and troughs. (a)   are the highest point of a wave, while ​ (b)   are the lowest point of a wave. Crests and troughs are parts of a ​ (c)  

• Crest
• trough
• Transverse Wave
• Longitudinal 
• Surface

Which of the following properties describes the bending of light as it enters a medium?

• reflection

• frequency

• refraction

• refraction

Which statement best describes diffraction?

• Light bounces off a medium.

• Light bends around an object.

• Light energy is absorbed by surrounding matter.

• 
  Light slows down as it passes through a medium.

A student is bouncing a ball off the wall in gym class to model for a fellow student how sound waves interact with surfaces. At first, the student bounces the ball off a concrete wall in the gym, shown in Model 1. Identify whether the model best represents reflection, absorption, or transmission.

• reflection

• absorption

• transmission