Reducing unwanted energy transfers

Question 1

What is friction?

Answer 1

• Objects rubbing against each other

Question 2

How can you reduce frictional forces?

Answer 2

• Lubrication

Question 3

What is lubrication?

Answer 3

• Liquids (oil)
• Can flow between objects easily
• Can coat objects

Question 4

How can you reduce the rate of energy transfer by heating?

Answer 4

• Insulation

Question 5

What are examples of insulation?

Answer 5

• Cavity walls –> made of inner + outer wall + air gap in between –> Air gap reduces dissipation
• Air gap filled with foam; reduce energy transfer by convection
• Double glazed windows

Question 6

How does loft insulation help with preventing energy transfer by heat?

Answer 6

• On floor + ceiling
• Fiberglass wool (good insulator)
• Reduces by convection
• Prevents convection