Waves: Light and Sound — Answer Key
Part A: Fix the Sentence
Each sentence has an error. Rewrite it correctly on the line.
1. Fix the sentence:
Grade 4 kids learns that radio waves carry music to our cars and homes.
Corrected: Grade 4 kids learn that radio waves carry music to our cars and homes.
'Kids' is plural, so use 'learn' for subject-verb agreement.
2. Fix the sentence:
Sunlight contain many colors of light waves, Grade 4 students discover.
Corrected: Sunlight contains many colors of light waves, Grade 4 students discover.
Singular noun 'sunlight' requires 'contains' for agreement.
3. Fix the sentence:
Ocean wave moves water up and down in Grade 4 science class.
Corrected: Ocean waves move water up and down in Grade 4 science class.
Use plural 'waves' with plural verb 'move' for agreement.
Part B: Fill in the Blank
Write the missing word or number on each line.
1. In Grade 4 science, the waves that carry songs to a car speaker are called radio waves.
Radio waves carry sound information to receivers.
2. Grade 4: a hospital uses x-rays to take pictures of bones inside the body.
X-rays are high-energy waves that show bones on film.
3. The ocean uses water waves that move up and down along the shore in Grade 4 lessons.
Ocean waves are mechanical water waves caused by wind.
4. Grade 4 students know that sunlight from the Sun gives Earth light and warmth.
Sunlight is visible light energy that travels from the Sun.
Part C: Short Answer
Answer each question in one or two complete sentences.
1. In Grade 4 words, name two waves you might use at home and tell what each one does.
Sample answer: Radio waves bring music to my radio so I can listen to songs. Microwaves in our microwave oven heat my food quickly by making the water inside it move and warm up.
Different waves do different jobs in everyday life.
2. Grade 4 question: how are ocean waves different from light waves?
Sample answer: Ocean waves are made of water that moves up and down, and they need water to travel. Light waves do not need water or air, and they can travel through empty space from the Sun to Earth.
Mechanical waves need a medium; light waves do not.