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🦴 How Do People Move? 💪

Muscles & Movement | DK Science • Level B1

Biceps Work

🧠 Vocabulary Bank

Let's learn the key words for today's lesson!

Muscle (n)
мышца
Contract / Relax (v)
сокращаться / расслабляться
Tendon (n)
сухожилие
Reflex (n)
рефлекс
Spinal cord (n)
спинной мозг
Force (n)
сила
Measure (v)
измерять
Antagonistic pairs (n)
мышцы-антагонисты

🔬 What Happens Inside Muscles?

Watch how muscle fibers contract and relax!

💪 Muscles can only PULL, not push!
🔄 They work in antagonistic pairs
⚡ Contraction happens in milliseconds

🏃 What Happens When You Exercise?

🏋️ Stronger Muscles

  • Body makes new muscle fibers
  • Muscles get bigger and stronger
  • The more you use them, the stronger they get!

💡 Fun fact: After exercise, muscles need rest to grow!

🏊 Longer & Stronger

  • Regular exercise = more endurance
  • Heart and breathing muscles strengthen
  • Running, swimming, cycling exercise heart & lungs

💡 Fun fact: Your heart is a muscle too!

🤔 Quick Question:

"Which muscles work when you run?"

⚡ The Magic of Reflexes

🤔 What happens if you touch something hot?

You pull your hand away IMMEDIATELY — before you even think about it! 🤚🔥

🔥 What is a Reflex?

  • A fast, automatic response
  • Your body's super-fast protection system
  • You don't think — you just react!

🎯 Real-Life Examples

  • Knee jerk reflex (doctor taps your knee)
  • Blinking when something flies at your eye
  • Pulling away from pain
🧠 The Amazing Reflex Path:

Touch 🔥 → Nerves → Spinal Cord → Nerves → Muscle Contracts! ✋
(The brain learns about it AFTER you move!)

🧪 TRY THIS! The Ruler Drop Test

Test your reflexes with a friend!

  1. Friend holds a 30cm ruler at the top.
  2. Put your fingers at 0cm (don't touch!).
  3. Friend drops it without warning.
  4. Catch it as fast as you can!
🏆 10cm = Super fast! (150ms)
👍 15cm = Good! (250ms)
💪 20cm+ = Keep practicing!

🔄 Muscles Work in Pairs

⭐ Muscles can only PULL, not push!

💪 Biceps

Biceps Contracted
  • Located at the top of your arm
  • Contracts (gets shorter) when you bend your arm
  • Pulls the lower arm UP
  • Relaxes when arm straightens

🙋‍♂️ Triceps

Triceps Contracted
  • Located under the arm (back side)
  • Contracts when you straighten your arm
  • Pulls the lower arm DOWN
  • Relaxes when arm bends

Visualizing the Swap:

Bending arm:    BICEP contracts TRICEP relaxes

Straightening: BICEP relaxes ⟷ TRICEP contracts

🎯 These are called Antagonistic Pairs!

🔗 Working Together: The Movement Team

🦴 JOINTS

  • Places where bones meet
  • Allow you to move
  • Have fluid inside for smooth movement
  • Examples: elbow, knee, shoulder

🔌 TENDONS

  • Tissues that connect muscles to bones
  • Work like strong ropes
  • Help muscles pull bones
  • Made of tough, fibrous tissue

🧠 NERVES

  • Send signals from brain to muscles
  • Tell muscles when to contract
  • Work at incredible speed!
🎪 Muscles + Joints + Tendons + Nerves = MOVEMENT TEAM!

📏 Measuring Muscle Power

💪 What is Force?

When a muscle contracts, it produces FORCE.

Force = the power of your muscles!

Measured in Newtons (N).

How to Measure It?

Use a special tool: DYNAMOMETER

Squeeze it with maximum effort.

It shows your strength in kilograms or Newtons.

🧮 CLIL Math Connection

Formula: Force (N) = Mass (kg) × 10

× 10 = 0 N

🍎 Fun Fact: 1 Newton ≈ the weight of one apple!

🏋️ Activity: Grip Strength Challenge

  1. Use a hand dynamometer.
  2. Hold in your dominant hand, squeeze maximum.
  3. Record the force.
  4. Repeat with non-dominant hand.
  5. Analyze: Which is stronger? Why?

❓ True or False?

Test your knowledge! Click "Check All Answers" when you are ready.

1. The biggest muscle in our body is in our behinds.

→ TRUE! (Gluteus maximus) 🍑

2. You use 300 different muscles just to stand up without falling over.

→ TRUE! It takes a lot of muscles to keep balance!

3. Muscles can push or pull.

→ FALSE! Muscles can only PULL! 💪

4. Reflexes go through your brain first.

→ FALSE! They go through the spinal cord for speed! ⚡

5. Your heart is a muscle.

→ TRUE! And it's working 24/7! ❤️
🎉

Congratulations!

You've completed "How Do People Move?"

What you learned today:

  • ✅ 8 new vocabulary words
  • ✅ How muscles contract and relax
  • ✅ The magic of reflexes
  • ✅ How to measure muscle force in Newtons
  • ✅ Why muscles work in antagonistic pairs

🚀 Final Challenge:

Try the Ruler Drop Test with your friends!
️ Measure your grip strength!
Share what you learned!