Thermal Energy Transfer

1. Thermal Energy Transfer Conductors & Insulators

2. Essential Standard • 6.P.3 Understand characteristics of energy transfer and interactions of matter and energy.

3. Clarifying Objective • 6.P .3.3Explain the suitability of materials for use in technological design based on a response to heat (to include conduction, expansion, and contraction) and electrical energy (conductors and insulators).

4. Essential Questions • What are examples of INSULATORS? • What are examples of CONDUCTORS? • How does electrical & thermal energy move through conductors? • Why does electrical & thermal energy NOT move through INSULATORS?

5. Electrical Energy • To understand how conductors & insulators work we have to understand atoms • If you remember atoms are the smallest pieces of matter • They make up everything except photons (which are part of an atom)

6. What is Electricity • http://www.youtube.com/watch?v=ZAFW4zdXpbY

7. Atoms • Atoms have a nucleus & an outer valence • In the nucleus & outer valence atoms are composed of 3 things • Protons- positively charged particles inside the nucleus • Neutrons- particles that have no electric charge inside the nucleus

8. Atoms • Electrons- negatively charged particles on the Outer Valance • Atoms will usually have the same number (equal) of protons & electrons to balance themselves out • Sometimes though there becomes more protons than electrons and then the atom becomes + charged

9. Excited Ions • The outermost electrons can escape away from the atom when it slams into another atom • When the electron escapes now the there are more protons than electrons and the atom has a + charge • An atom that has a + charge is called an ion • Because there are more protons + than electrons the atom gets excited and vibrates

10. Jumping Electrons • When electrons escape it goes to the next atom • This will cause the electron in the next atom to jump to a different atom

11. Jumping Electrons

12. Jumping Electrons = Electricity Transfer (Heat/Thermal Energy Transfer) • When the electron has jumped atoms from one side to another it has passed electricity • This is how we get our power/electricity in our houses

13. Essential Questions • Get with a partner and answer… • How does electrical & thermal energy move through conductors?

14. Conductors & Insulators Opposite • Conductors are Insulators OPPOSITES from each other • This means if a material is a good conductor it is a bad insulator • If a material is a good insulator it is a bad conductor

15. Conductors • http://www.youtube.com/watch?v=qUhxmXZwPmg • 4:30-7:15

16. Conductors • Conductors are solids that energy can travel through • This could be thermal energy (heat) electrical energy or other energy • There are good conductors & bad conductors

17. Good Conductors • Good conductors are solids that have atoms that are very dense • The more dense the atoms the better conductors they will be • This is because the atoms are more tightly compacted together

18. Good Conductors • Good conductors atoms are close enough to each other that the electrons can bounce from one atom to the next passing the heat or electricity

19. Bad Conductors • Bad conductors of electricity & thermal energy exist in three different forms • Gasses are bad conductors because the particles are so far apart from each other • Liquids are bad conductors for the same reason • Solids that are not dense are also bad conductors

20. Why are They Bad Conductors • These are all bad conductors because the atom particles are not dense and they cant jump from atom to atom • The worst kind of conductor is actually called an insulator

21. Insulators • Insulators are materials used to keep heat & sound contained inside something • Insulators keep heat inside something • Insulators keep electricity inside something

22. Insulator • http://www.youtube.com/watch?v=qUhxmXZwPmg • 7:15-8:15

23. Essential Questions • Get with a partner and answer… • Why does electrical & thermal energy NOT move through INSULATORS?

24. Good Insulators • Good insulators will NOT allow electrons to move from one end to another • They trap the electrons keeping the heat or electricity inside something

25. What makes a Good Insulator • Materials that have many different types of atoms make good insulators (Styrofoam cups) • This is because the DIFFERENT types of atoms BOND together • Now not only are the atoms are the same connected together but also those atoms are forming BONDS to other types of atoms

26. What makes a Good Insulator • This forms a wall and does not allow the electrons to escape from one atom to the next • If the electrons cant escape the neither the thermal energy or electrical energy can be transferred

27. Great Conductors • Have to be solids • Metals from the periodic table are the best because they are just one kind of atom & very dense • Copper • Aluminum • Gold • Silver • People & Animals

28. Great Insulators • Solid nonmetals that are NOT DENSE • Styrofoam • koozies • Rubber • Plastic • Glass • Ceramic/Porcelain • Clothing

29. Essential Questions • Get with a partner and answer… • What are examples of INSULATORS? • What are examples of CONDUCTORS?

30. EOG Questions • Why are some coffee cups composed of ceramic material? • A) Ceramic materials are conductors that limit heat transfer. • B) Ceramic materials are insulators that limit heat transfer. • C) Ceramic materials are conductors that aid heat transfer. • D) Ceramic materials are insulators that aid heat transfer.

31. EOG Questions • A worker for an electrical company is preparing to fix a power line. Why would he put on rubber gloves before working with any power lines? • A) Rubber is a poor conductor of heat but a good conductor of electricity. • B) Rubber is a good conductor of heat but a poor conductor of electricity. • C) Rubber is a poor conductor of heat and electricity. • D) Rubber is a good conductor of heat and electricity.