Grade 7 STEM
CBSE Grade 7 Science
NCERT Chapter 3
Thermal Physics
Heat, Temperature & Convection Lab
Explore clinical vs. laboratory thermometers, temperature scale conversions, thermal conduction, convection currents, and radiation absorption.
Virtual Thermometers
Clinical vs. LaboratoryClinical Thermometer
Kink
42°C (Max)
39°C (High Fever)
37°C (Normal)
35°C (Min)
37.0 °C
(Range: 35°C to 42°C)
Laboratory Thermometer
110°C (Max)
100°C (Boiling)
50°C
25°C (Room)
0°C (Freezing)
-10°C (Min)
25.0 °C
(Range: -10°C to 110°C)
Why does a clinical thermometer have a kink?
The kink (constriction) prevents the mercury column from falling back on its own after being taken out of the mouth, giving accurate reading time!
3-Way Temperature Scale Studio
Adjust any scale to see automatic conversions and step-by-step NCERT formulas.
°C
°F
K
Quick NCERT Benchmark Benchmarks:
Step-by-Step Conversion Formulas:
Celsius to Fahrenheit:
F = (C × 9/5) + 32 = (37 × 1.8) + 32 = 98.6 °F
Celsius to Kelvin:
K = C + 273.15 = 37 + 273.15 = 310.15 K
Universal Relation: C / 5 = (F - 32) / 9 = (K - 273.15) / 5
Conduction Simulation: Wax Pin Drops
NCERT Activity 3.6: Observe heat transfer through solids via direct particle vibration
Standby
Gentle
Medium
Roaring Blue
Drop Log & Science Facts
Rod Temperatures:
Hot End: 25°C
Mid: 25°C
Cold End: 25°C
Wax Pin Drop Tracker:
- Pin 1 (Near Flame) Attached
- Pin 2 (25% distance) Attached
- Pin 3 (50% distance) Attached
- Pin 4 (75% distance) Attached
- Pin 5 (Far End) Attached
Conduction Definition: The process by which heat is transferred from the hotter end to the colder end of an object without the actual movement of the particles. Solid metals conduct heat rapidly!
Sea Breeze vs. Land Breeze Simulator
NCERT Section 3.4: Convection currents in nature caused by differential heating
Land Temperature:
36 °C
Land heats up fast during the day and cools down fast at night (low specific heat).
Sea / Water Temperature:
26 °C
Water warms up slower and cools down slower than land (high specific heat).
How Convection Works
☀️ Daytime Sea Breeze
- Sun heats both land and sea, but land heats up much faster.
- Warm air above the land expands, becomes lighter, and rises.
- Cooler, denser air from above the sea moves in towards the land to take its place.
- This cool wind blowing from the sea towards the land is called the Sea Breeze!
Convection in Liquid (Beaker):
Warm water expands at bottom → rises up. Cool dense water at top sinks → sets up a continuous convection current.
Why do coastal houses have windows facing the sea?
To receive the refreshing, cool sea breeze during hot summer days!
Radiation Lab: Black vs. White Surfaces
NCERT Activity 3.10 & 3.11: Absorption and emission of radiant heatLive Temperature Readout
Black Painted Can
25.0 °C
Dull, dark surfaces are great absorbers and great emitters of radiant heat.
Shiny White / Silver Can
25.0 °C
Light, shiny surfaces reflect most thermal radiation and stay cooler.
Why wear light clothes in summer?
Light-coloured clothes reflect most of the heat from the sun that falls on them, keeping us comfortable and cool. Dark clothes absorb heat, which is why we prefer them in cold winters!CBSE Grade 7 NCERT Summary: Chapter 3 (Heat)
| Feature | Clinical Thermometer | Laboratory Thermometer |
|---|---|---|
| Intended Purpose | Measures human body temperature only | Measures temperature of chemicals, water, objects |
| Temperature Range | 35°C to 42°C (94°F to 108°F) | -10°C to 110°C |
| Presence of Kink | Yes (prevents mercury drop) | No (reading must be taken inside liquid) |
| Liquid Used | Mercury (or Digital thermistor) | Mercury or Coloured Alcohol |
1. Conduction
Transfer of heat in solids from hotter to colder end without movement of particles.
Examples: Metal spoon in hot soup, frying pan bottom.
2. Convection
Transfer of heat in liquids and gases by the actual physical movement of particles.
Examples: Boiling water, sea breeze & land breeze.
3. Radiation
Transfer of heat through electromagnetic waves without any medium required.
Examples: Sun's heat reaching Earth, warmth from campfire.