Science year 2.2: energy effects

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

2.2 Energy Effects

Learning goals

Learning goals

- Explain the three different types of heat transfer

- Identify which type of transfer is present in a situation

- Explain the difference between conductors and isolators and
   describe how they should be used

- Identify if a reaction is endothermic or exothermic

- explain the effect of catalysts on chemical reactions

What was renewable energy?

1. New types of energy
2. It does not run out, it renews itself
3. energy that consists of waves
4. It runs out, so we won’t be able to use it forever

What does the 'law of conservation of energy' mean?

1. energy can not convert from one form to another
2. Energy has to uphold the law
3. Energy is never lost
4. Energy is lost when converted

Nuclear energy is

1. sustainable
2. Renewable
3. sustainable and renewable
4. Not sustainable nor renewable

heat transfer via direct contact.

heat transfer via air or water.

heat transfer via light/ electromagnetic radiation

convection

conduction

Radiation

Conduction

Conduction = heat transfer via direct contact.

Example = a pan transfers heat to food

Conduction

Heat transfer through direct contact between the particles in a substance

Insulators: not good at conducting heat 

plastic, cork, air, wood

Conductors: good at conducting heat

metals; copper, silver

Convection

Convection = 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

moves in all directions

does not need medium

Radiation

Heat transfer in all directions through electromagnetic waves

Radiation does not need a medium to go from one place to another

Radiation can move through space 

when a chemical reaction needs heat, it's called endothermic

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

exotherm

endotherm

Chemical Energy

Catalysts

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

convection is heat transfer through...

1. solid materials
2. fluids and gasses
3. nothing
4. glass

a catalyst makes is harder for a reaction to happen

1. true
2. false

Burning coal on a barbecue is an exothermic reaction

1. true
2. false

what is needed for conduction

1. molecules that can move around freely
2. no molecules at all
3. molecules very close to each other
4. al lot of different types of molecules

homework

Make: 12 until 21

Pages 18 until 22