YR2_T2_LSN2

• Science
• Middelbare school
• havo, vwo
• Leerjaar 2

Get ready:

• Your Macbook (join the lessonup)
• Your notebook.
• Your textbook.
• Pen & highlighter

YR2_T2_LSN3

Topic 2.2 Energy effects

Plan for today:

• Explanation T2.2 Energy effects
  
• Make homework 

Learning goals

I can…

• Explain the three different types of heat transfer.
• Identify which type of heat transfer is present in a situation.
• Explain the difference between conductors and insulators and describe how they should be used.
• Identify if a chemical reaction is exothermic or endothermic.
• Explain the effect of catalysts on chemical reactions.

Key words

• Conduction
• Conductors
• Insulators
• Convection
• Radiation
• Exothermic
• Endothermic
• Activation energy
• Catalyst

Enzymes

Heat transfer

Heat can easily be transferred from one place to another.

Heat always moves from warmer to cooler places.

Heat transfer happens in 3 ways:

Conduction

Conduction is heat transfer via direct contact.

• Example:  a pan transfers heat to food.

Conduction

Heat transfer through direct contact between the particles in a substance

• Conductors: good at conducting heat - metals; copper, silver
• Insulators: not good at conducting heat - plastic, cork, air, wood

Convection

Convection is heat transfer via air or water. 

• Example:  radiator warms the air in a room

Hot air has a lower density than cold air, therefore it will rise upwards

Cold air has a higher density than hot air, therefore it will sink

Radiation

Radiation is heat transfer without molecules

It travels in waves

 Endothermic

When a chemical reaction needs heat, it's called endothermic.

Exothermic

Chemical reactions that release thermal energy(heat) to the environment are called exothermic.

Catalysis

Each reaction needs energy to get started → activation energy

• Example: Heat is needed to start a fire (ignition temperature)

The activation energy can be 

lowered by catalysts 

(certain molecules) 

There are also catalysts 

in your body, 

they are called enzymes

Homework

• Make exercises 12-21 of topic 2.2 in your workbook
•  Prepare labjournal for skills 6 ''Exothermic vs endothermic''