4th grade light, sound and waves

Question 1

Water is poured into identical glass bottles to different levels. You blow across the tops. Which bottle gives the highest note?

• A. the one with the most water (shortest air column)
• B. they are all the same
• C. the empty one
• D. the one with the least water

Question 2

Drop a stone in a still pond. What carries energy out to the edge?

• A. the ripples spreading out in circles
• B. the wind
• C. the stone rolling along the bottom
• D. the fish

Question 3

What is the job of the eyelid?

• A. protects the eye and spreads tears
• B. the coloured ring that makes the pupil bigger or smaller
• C. carries signals from the eye to the brain
• D. the layer at the back that senses light

Question 4

In a long spring (slinky) on the floor, 6 complete waves fit into 12 cm. What is the wavelength?

Answer cm

Question 5

True or false? Sound can travel through water.

• A. True
• B. False

Question 6

Pitch and loudness: which statement is NOT true?

• A. Loud sounds always have a high pitch.
• B. Faster vibrations make higher-pitched sounds.
• C. Pitch is how high or low a sound is.
• D. Humans can hear sounds from about 20 Hz to 20 000 Hz.

Question 7

Two sound waves are drawn the same way. Wave A has an amplitude of 6 squares and wave B has 4 squares. Which is the LOUDER sound?

• A. wave A
• B. wave B

Question 8

What is the ringed part of this wave called?

• A. amplitude
• B. trough
• C. wavelength
• D. crest (peak)

Question 9

Phones and computers send pictures and music as patterns of just two signals, like on and off. What is this called?

• A. a shadow
• B. an echo
• C. digital information
• D. a rainbow

Question 10

Waves and energy: which statement is true?

• A. Ripples on a pond carry the stone to the edge.
• B. Surfers are carried by water travelling across the whole ocean.
• C. A wave can travel without any energy.
• D. Wave energy machines can generate renewable electricity.

Question 11

A torch (flashlight) flashes short (•) and long (–) pulses. Use the key to decode the message. Key: S = ••• U = ••– N = –• Message: ••• / ••– / –•

Answer 

Question 12

Why do cats' pupils open very wide at night?

• A. To look scary.
• B. To keep dust out.
• C. To make light.
• D. To let in as much light as possible.

Question 13

Which word means the distance from one crest to the next crest?

• A. amplitude
• B. trough
• C. crest (peak)
• D. wavelength

Question 14

A guitarist plucks a string harder. What changes in the sound wave?

• A. The wavelength becomes zero.
• B. The amplitude gets smaller.
• C. The wave stops.
• D. The amplitude gets bigger, so the sound is louder.

Question 15

Pitch and loudness: which statement is true?

• A. Hitting a drum harder makes a higher note.
• B. Bigger vibrations make louder sounds.
• C. Loud sounds always have a high pitch.
• D. Longer strings make higher notes.