به انگلیسی

Talking about light and sound

علوم · موج‌ها، نور و صدا · سن ۶ تا ۸ سال

نام ______________________ تاریخ ____________

Eli wants to make a shadow puppet on the wall. He already has a flashlight. What else does he need?
- Something opaque, like his hand
- Something transparent, like clear glass
- One more flashlight
Sam holds his book up to a lamp. No light shines through it at all. What is the book?
- It is transparent
- It is opaque
- It is translucent
Zoe plucks a rubber band and hears a twang. What made the twang sound?
- The band moving back and forth after the pluck
- The band staying still while light shines on it
- The band changing colour without moving at all
A shadow can form even if there is no light source.
دور یکی دایره کشیدن: درست نادرست
You look through a plastic shower curtain and can only see blurry shapes. What is the curtain?
- Transparent
- Translucent
- Opaque
A drummer hits the drum harder than before. What happens to the volume?
- It gets louder
- It gets softer
- It stays the same
Two strings vibrate: one fast, one slow. Which words correctly describe their pitch?
- Fast means louder; slow means softer
- Fast and slow give the same pitch
- Fast means higher; slow means lower
Leo sees a toy clearly through a clear plastic box but calls the box opaque. Which words has he mixed up?
- Opaque and transparent
- Translucent and opaque
- Transparent and translucent

پاسخ‌نامه

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Something opaque, like his hand · A shadow needs light plus something that blocks it. Eli's hand is opaque, so it blocks the flashlight beam and makes a puppet shape on the wall.
It is opaque · No light coming through at all is exactly what opaque means. A transparent thing would let the light through clearly, and a translucent thing would let some through.
The band moving back and forth after the pluck · Plucking makes the band wiggle back and forth very fast. That fast wiggle is a vibration, and vibrations make sound.
نادرست · Without a light source, there is no light to block, so no shadow can form.
Translucent · Light passes through the curtain but is scattered, so shapes look blurry. That means the curtain is translucent.
It gets louder · Hitting harder makes bigger vibrations, and bigger vibrations make a louder sound.
Fast means higher; slow means lower · Faster vibrations make a higher pitch, and slower vibrations make a lower pitch, no matter how loud they are.
Opaque and transparent · A clear view through the box shows that it is transparent, not opaque. Leo has mixed up opaque and transparent.