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Body Lab 3-5 / Week 07 / Friday
5/6
Week 07 · Brain and Nerves

Friday

Sense, think, act
// The control center and its messengers
⏱ about 15 min

Friday: Sense, Think, Act

Rocket holds a ruler up high. "I can catch this before it hits the floor!" he says. He drops it and grabs at air.

Raven giggles. "What do you notice? Did you know when it would fall?"

Nova circles the ruler. "A good test needs a plan," she says. "Who drops, and who catches?"

Rocket grabs a pencil to plan.

Your body's message loop

Your senses notice something. That is the "sense" step.

Nerves carry the message to your brain. Your brain decides what to do. That is "think".

Nerves carry orders to your muscles. Your muscles move. That is "act".

The time between noticing and moving is called reaction time.

PUT THE MESSAGE LOOP IN ORDER
  • ?Your brain decides to grab.
  • ?Nerves carry the message to your brain.
  • ?Your eyes see the ruler start to fall.
  • ?Your fingers pinch the ruler.
  • ?Nerves carry orders to your hand muscles.
WHY THIS EXERCISEYour senses, brain, nerves and muscles work as one system.

The ruler drop test

A partner holds a ruler at the high end. It hangs down between your open fingers.

Your partner lets go without warning. You pinch it as fast as you can.

Read the number where your fingers caught it.

A smaller number means the ruler fell a shorter way. That means a faster catch!

TryCatch point in centimeters (made-up practice numbers)
118
215
312
READ THE PRACTICE DATA
  • Read the question.
  • Tap your answer.
In these made-up numbers, which try was the fastest catch?
Why should you do more than one try?
The time between noticing and moving is called reaction ____.
A smaller catch number means a ____ catch.
Fair test ruleTrue or false?
Use the same ruler for every try.?
The catcher should know exactly when the ruler will drop.?
Start the ruler at the same spot each time.?
WHY THIS EXERCISEKeeping everything the same except the catch makes the test fair.
In the made-up data, how many centimeters shorter was try 3 than try 1?
WHY THIS EXERCISEEighteen minus twelve is six, so try 3 stopped the ruler 6 centimeters sooner.
What is the "think" step of the message loop done by?
WHY THIS EXERCISEThe brain decides what to do with what the senses notice.
Try it
Find a 30 centimeter ruler (a 12 inch ruler).
Check where the zero is. That end goes between your fingers.
Make a table with three rows for tomorrow's tries.

Plan complete, scientist! Tomorrow is Body Lab Day. Bring a family member for the ruler drop.

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