📘 1.1 Physical and Non-Physical Quantities — Complete Learning Guide

🌟 Introduction

Look around your room — maybe a table, clock, or cup of tea ☕.
Some things can be measured, while others cannot.
This idea builds the foundation of Physical and Non-Physical Quantities, the first topic of PTCB 9th Class Physics Chapter 1 (New Syllabus 2025).

📊 What Are Physical Quantities?

Physical quantities are things that can be measured using scientific instruments.
They always have a number + unit (like 5 m, 10 s, 37°C).

✅ Examples

• 📏 Length — measured with a ruler

• ⏰ Time — measured with a clock

• 🌡️ Temperature — measured with a thermometer

• ⚖️ Weight — measured with a scale

🎯 Key Points

✔️ Can be measured
✔️ Have numerical values & units (50 kg, 37°C)
✔️ Same for everyone
✔️ Basic requirement for scientific studies

💭 What Are Non-Physical Quantities?

Non-physical quantities cannot be measured using any instrument.
They don’t have numbers, units, or dimensions.

✅ Examples

• ❤️ Love

• 🌺 Beauty

• 😨 Fear

• 😊 Happiness

• 🧠 Wisdom

🎯 Key Points

✔️ Cannot be measured
✔️ No units or numbers
✔️ Differ from person to person
✔️ Connected to emotions, feelings, and thoughts

🔍 Comparison Table

🌍 Example 1: Going to School 🎒

Measurable (Physical Quantities)

• 📏 Distance → 2 km

• ⏰ Time → 15 min

• 🌡️ Temperature → 30°C

• 🚲 Speed → 8 km/h

Non-Measurable (Non-Physical Quantities)

• 😊 Happiness while meeting friends

• 😰 Nervousness before exam

• 💪 Confidence during test

• ❤️ Love for your teacher

🍰 Example 2: Baking a Cake 🎂

Measurable (Physical Quantities)

• ⚖️ Flour → 500 g

• 🥛 Milk → 200 ml

• ⏱️ Baking time → 30 min

• 🌡️ Oven temperature → 180°C

Non-Measurable (Non-Physical Quantities)

• 😋 Taste

• 🎨 Appearance

• 😊 Joy of sharing

• 💖 Love while cooking

🎯 Why Both Are Important

Physical Quantities help us:

• Build structures 🏗️

• Perform experiments 🔬

• Make scientific predictions 📊

Non-Physical Quantities help us:

• Feel emotions 💭

• Appreciate beauty 🌸

• Strengthen relationships 🤝

✨ Final Thought

We can measure the length of a hug…
…but not the love in it. ❤️
Both play an important role — one in science, one in life.

“Not everything that counts can be counted, and not everything that can be counted, counts.” 💫

📝 Quiz: Physical vs Non-Physical Quantities (Complete Answer Table)

💡 Quick Memory Tip

“If you can put a NUMBER on it → PHYSICAL.
If it’s a FEELING → NON-PHYSICAL.” ✨

❓ Quick Concept Check

Q: Does a non-physical quantity have dimensions?
A: ❌ No.
It has no units, no instrument, and no measurable value.