Methods of Heat Transfer

1. HEAT TRANSFER
By: Ana Mae Ignacio Recilla

2. Objectives:
• Explain conduction, convection and radiation as methods
of heat transfer
• Distinguish the type of heat transfer that works on some
real-life situations
• Correctly infer the conditions necessary for heat transfer
to occur

3. Pre-test (5mins)
Identify the method of heat transfer taking place (conduction,
convection, radiation in every situation.
1. Hot milk is stirred with a spoon, the spoon gets hot.
2. The air at the side near the burning gas stove gets warm .
3. The flame of the candle will slowly warm the metal rod and
transfer the heat directly to the rod.
4. The concrete pews at the park get so hot during the day that
you can’t sit on it.
5. A pot becomes hot because it is placed on a stove that is on.

4. For numbers 6-8
a. When heat is transferred through waves across a distance
b. When heat is transferred through circulation of liquid or gases
c. When heat is transferred from objects that are in direct contact.
6. Which describes CONDUCTION?
7. Which describes CONVECTION?
8. Which describes RADIATION?

5. 9. Which of the following is needed for convection to happen?
a. Liquid or gas c. Electromagnetic waves
b. Light rays d. Vacuum
10. Which path can radiation travel through?
a. Solid c. Vacuum
b. Liquid and gas d. All of the above

6. Thermal Energy
•It is the energy possessed within the object or
the system due to the movement of particles.
•The faster the particles move, the more
thermal energy is possesses and the higher the
temperature that is measured

7. Temperature
• Refers to the hotness or coldness of an object.
• It is measured in
• Degree Celcius - °C
• Degree Fahrenheit - °F
• Kelvin - K
• Rankine - R

8. Thermometer
•A device used to measure temperature.
•Has 2 kinds
• Clinical thermometer – determines body temperature
• Laboratory thermometer – used in laboratory
experiments

9. Heat
•It is a form of energy that is transferred
between two objects at different
temperature od simply “energy in
transit”.

10. 3 Methods of Heat Transfer
1. CONDUCTION
• Heat transfer by conduction when objects are in direct
contact
• It involves transfer f energy from particle to particle
• The energy moves from one place to another but the
particles do not.

11. 2. CONVECTION
• Heat transfer by the movement of the molecules of fluids itself
• It occurs in all fluids (both liquids and gases)
• The moving fluids carry energy in it.
• The fluid flows from a region of high temperature to low
temperature.

12. Convection current
• The situation where hot fluid rises and cool fluid settles
down
A. Natural Convection – heat flows without any assistance
from external sources.
B. Forced Convection – Heat flows b an external factors (fan,
wind)
You can hold your fingers beside the candle flame without harm but not above the flame. Why? 12

13. 3. RADIATION
• The transfer of heat involving the carrying of energy from an origin
to the space surrounding it.
• The energy is carried by electromagnetic waves and does not involve
the movement or the interaction of matter.
Thermal Radiation can travel through matter (solid, liquid, gas) or
through a region of space that is void (vacuum).