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Hi! I’m Santiago. This is my cousin Valeria.
Valeria is a park ranger. She works at a park where there are trees and trails and a river.
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There’s even a big cave.
Valeria said, “I’m going to explore the cave tomorrow. Do you want to come?”
“Yes!” I cried.
“It will be cold and dark in there,” Valeria said.
That night, I thought about how to get ready for our cave adventure.
My jacket would keep out the cold.
But I wondered: Can I see in the dark?
When I went to bed that night, it was dark in my room. Really dark.
Just a little bit of light leaked under the door from the light in the hall.
I looked around my room.
At first, I couldn’t see anything.
Then I could see a little bit.
After a while, I could see a lot!
The next morning, Valeria and I hiked to the cave.
She gave me a bright yellow helmet to wear. It had a light on top.
“This helmet will protect you from falling rocks,” she said. “The light will help you see in the dark."
I put on my helmet, but I knew I wouldn’t need the light.
A dirt path led into the cave. Valeria walked inside and I followed. There were rocks all around.
When I looked behind me, I could see the blue sky.
When I looked in front of me, I could see Valeria just fine.
I knew I’d be able to see inside the cave!
We walked deeper into the cave. Valeria turned on her helmet light. She told me to turn mine on, too.
“I don’t need it,” I told her. “I can see in the dark.”
“Let’s try an experiment,” Valeria said. “Hold my hand and we’ll go deeper into the cave. Then you can decide about using your light.”
I held Valeria’s hand. When we went deeper into the cave, the path went around a corner.
I looked behind me, but couldn’t see the sunlight any more.
Valeria’s headlamp lit up the rocks.
“I’m going to turn off my light,” Valeria said. “Let’s see what happens.”
“Let’s do it!” I said. I knew I’d be able to see just fine.
Valeria turned out her helmet light. It got very dark.
I held her hand tighter.
I looked in front of me and behind me.
This is all I could see.
“Well?” Valeria said. “Do you think you need your light?”
“We need to wait a minute,” I told her. “Sometimes it takes a while to see in the dark.”
“Okay, I’ll count to twenty.”
While Valeria counted, I tried everything to see.
I blinked and blinked. I opened my eyes wide. I scrunched my eyes closed, then opened them really fast.
Still, this was all I could see.
“What do you see?” Valeria asked.
“Nothing!” I said.
“Ready for some light?”
“I guess so,” I said.
Valeria turned on her headlamp. She switched on my headlamp, too.
Suddenly I could see the cave around us.
“Wow! It’s beautiful!” I cried.
“I don’t get it,” I said. “I can see in the dark in my bedroom at night. Why not here?”
“How is being in this cave different from your bedroom at night?” Valeria asked.
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Stop & Talk
I thought about what Valeria had asked.
“I have windows in my bedroom,” I said. “Moonlight can shine in the windows. So can light from streetlights.”
“Right,” Valeria said. “Anything else?”
“There’s a light in the hall,” I replied. “There’s a night-light in my room, too. Maybe I do need light to see.”
“I guess we’d better leave our helmet lights on,” I told Valeria. “We can’t see without the light, and I don’t want to miss any more of this cave!”
THE END
You may not be able to take a field trip into a deep, dark cave, but you can make a Dark Box that lets students experiment with seeing in dim light and darkness.
Go to the next slide for instructions.
A Dark Box is an opaque box with a hole in one end. Students take turns placing a message inside the box and trying to read the message through the opening. How much light do they need to see the message clearly? Students learn that they can see objects only when light shines on them. See Activity Prep below.
