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Science Launch G4 / Week 08 / Wednesday
3/6
Week 08 · Secret Codes

Wednesday

Investigation: Taps or flashes?
// Patterns that carry information
⏱ about 15 min

Wednesday: Taps or flashes?

Rocket wants to send a message across the backyard. "Flashlight blinks are the best," he says.

Raven shakes her head. "I think taps on the fence might be better. You can hear them without looking."

"Only one way to know," Rocket says. "Let's test it!"

Raven nods. "What do you notice we need to measure?"

Nova sets a timer glowing above them. "My hint," she says. "Send the same message both ways. Count the time and the mistakes."

What you need

  • A small flashlight with AA batteries
  • A table or a wooden spoon for tapping
  • A clock or timer
  • Paper and a pencil for each person
  • A partner
Safety first
Point the flashlight at the wall or ceiling, never into eyes.
Tap gently so nothing breaks.

Steps

  1. Pick a short message, like SEA or HAT. Do not tell your partner.
  2. Sit across the room from your partner.
  3. Send the message with flashlight blinks. Your partner writes the dots and dashes, then decodes them.
  4. Write how many seconds it took and how many letters were wrong.
  5. Pick a new message the same length.
  6. Send it with taps. Write the time and mistakes again.
MAKE A PREDICTION
  • Read the question.
  • Tap your answer.
Which way needs your partner to watch you the whole time?
Way of sendingSecondsLetters wrong
Flashlight blinks
Taps
Flashlight blinks carry the pattern with ____.
Taps carry the pattern with ____.

Reading your results

Look at your table. Which way was faster? Which way had fewer letters wrong?

Engineers compare solutions using evidence like this.

Sometimes one way is faster, but the other way makes fewer mistakes.

ENGINEER THINKING
  • Read the question.
  • Tap your answer.
Why did you send messages of the same length both ways?
Which way works better in a dark room?
Which way works if your partner cannot see you?
StatementTrue or false?
Flashlight blinks carry a pattern with light.?
Taps carry a pattern with sound.?
Your partner can read blinks with eyes closed.?
WHY THIS EXERCISELight signals need eyes. Sound signals need ears.
You want to send a message in a noisy room. Should you use blinks or taps?
WHY THIS EXERCISELight signals are not drowned out by noise.

You compared two solutions like an engineer. Tomorrow we send a whole picture using only numbers!

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