1. Insulators and Conductors
Objective: Describe insulators and conductors. Identify materials that are good insulators and conductors.

2. Heat Transfer Heat always moves from a warmer place to a cooler place.
Hot objects in a cooler room will cool to room temperature after the hot object transfers some of their heat to the cold object.
Cold objects in a warmer room will heat up to room temperature.

3. Why does metal feel colder than wood, if they are both at the same temperature?
Metal is a conductor, wood is an insulator. Metal conducts the heat away from your hands. Wood does not conduct the heat away from your hands as well as the metal, so the wood feels warmer than the metal.

4. Then can I transfer the potatoes from the pan to my stomach?
At home energy is TRANSFERRED in lots of ways. Look at this saucepan where potatoes are being boiled.
Heat energy is being transferred from the electric ring to the glass hob.
Heat energy is being transferred from the glass hob to the metal saucepan.
Heat energy is being transferred from the metal saucepan to the water and potatoes.
Then can I transfer the potatoes from the pan to my stomach?

5. What do we call things that allow heat energy to transfer easily?
They are called conductors.
Solid fuel stove
Metal hob
The heat energy is transferred from the burning fuel, to the metal hob, to the metal saucepan and kettle and then to the water. Heat energy is being transferred from the water to the spoon in the saucepan too.
Good conductors
feel cold when there is
no source of heat. They don’t retain heat but let it be transferred away.

6. What do you know about all these things?
Sometimes we don’t want heat to be transferred, we want to keep the heat in.
What do you know about all these things?
Hats, coats, gloves and scarves are all insulators. They make it difficult for heat energy to be transferred from your body to the cold air, so they keep you warm.

7. What is a conductor?
A conductor is something which allows electricity to flow through.
An example of a conductor is:
Scissors
Paper clip
Aluminum foil
Iron
Steel
Copper

8. What are Conductors?
Conductors allow heat to move easily through them.
Allow heat to pass easily from an object. Like a train conductor moves from the front of the train to the back. A train conductor allows people to pass onto the train like a heat conductor allows the heat to pass easily.
We use conductors when we use our pots and pans because we want the heat to pass/transfer to our food to heat it.

9. which containers conduct heat energy most easily?
Look at these containers. They will be filled with hot water.
Which ones do you think are conductors that will allow the transfer of heat energy most easily?
How will I know
which containers conduct heat energy most easily?
glass
Paper cup
Clue
Polystyrene cup
Metalmug
Pottery
mug
Plastic mug

10. Examples of Conductors
Metal

11. Glass

12. Paper

13. Electrical Conductor Example:
Objects that allow electrical charge to flow easily
Example:
The coil from a electric heater gets hot and conducts electricity well

14. Conductor: a material that transmits electrical energy easily
Metals make the best conductors

15. Property of Electrical Conductor:
In all good conductors electric current flows through them without resistance
Example: Electricity flows through the coil in the power line coils easily and without resistance

16. Good Conductors
Metal is a good conductor of electricity

17. What is a Insulator?
An insulator is what help keeps electricity from not flowing
Examples of insulators are:
Cotton
Plastic
Rubber

18. Insulators
We use INsulators when we want to keep the heat IN – so the amount of heat/temperature stays about the same OR we use an insulator when we DO NOT want the heat to pass through easily, so we won’t be burnt.
Example: Thermos, Oven Mitts, Styrofoam cup with hot coffee, Winter Jacket, Rubber, blanket.

19. These are insulators too.
Look at these things.
These are insulators too.
What do they do?
Tea cosy, burger box and thermos flask all prevent the transfer of heat.

20. Thermos
A thermos is a container that is capable of keeping hot items hot and cold items cold.
A thermos, a cooler or even an insulated cup works by preventing transfers of heat!

21. What are Insulators?
Insulators are materials that do not allow heat to move easily through them.

22. Conductors & Insulators
Insulator: a material that resists or blocks the flow of electrons through it

23. Good Insulators:

24. Why Metals Feel Cool to the Touch at Room Temperature
Room temperature is cooler than human body temperature.
Heat is ONLY noticed when there is a transfer!
Metals quickly conduct heat from your body throughout the metal (since it is taking heat, it feels cold).
Wood and plastic don’t conduct heat quickly, so not as much is taken from your skin.
Good insulators normally have a lot of space for air, because gases doesn’t conduct heat as well as solids.

25. These are pictures of conductors and Insulators

26. Insulator or Conductor??

27. Metal scissors Cotton T shirt
Here is a fun activity. Use your fingers to find out which materials are good conductors and which are good insulators. Use a table like this one.
Conductors
Feel cold to touch.
Insulators
Do not feel cold to touch.
Metal scissors
Cotton T shirt
Things I am not sure about

28. 1. Cotton ball

29. 2. Metal scissors

30. 3. Metal cookie sheet

31. 4. Notebook paper

32. 5. Rubber duck

33. 6. Curling Iron

34. 7. Glass Cup

35. 8. Electric Heater (coils)

36. 9. Plastic Trash Can

37. 10. Metal Wire

38. 11. Plastic Spatula

39. 12. Copper Penny

40. 13. Iron frying pan

41. 14. Drawing chalk

42. 15. Eye on the stove

43. Procedure
Draw the following picture in your science journal.

44. Let me demonstrate…
Set up the equipment as shown and tape the wires to the battery.
Does anything happen?
Does the banana allow electricity to flow through the circuit and light the bulb?
Is it a conductor or an insulator? Why or why not?

45. Inquiring Minds Want to Know. Conductor or Insulator
Inquiring Minds Want to Know! Conductor or Insulator? That is the question!
Now take the bag of materials and spread them out in front of you.
Draw the following table in your journal.
As you test each item, record whether it was a conductor or and insulator with a
Item
Conductor
Insulator
Did the bulb light?
Spoon
Paper clip
pencil
Rubber band
eraser
Foil
Nail
coin

46. What is a circuit tester? Example of a circuit tester
Now its your turn…
What is a circuit tester?
Use of a circuit tester: To test whether the material is a good electrical conductor.
Example of a circuit tester

47. Reducing Heat Loss From The Home
Heat can be lost through many places at home. These include:
Roof
Walls
Gaps around doors and windows
Floors
Windows

48. Reducing Heat Loss From The Home
We can reduce heat loss from our homes by using different methods of insulation.
These include:
Double glazing
Loft Insulation
Cavity Wall Insulation
Carpets, Curtains, Draught Excluders

49. Expansion and Contraction

50. Expansion and Contraction
Materials expand or contract when subjected to changes in temperature.
Most materials expand when they are heated (particles move farther apart), and contract when they are cooled (particles move closer together).
Expand- increase in volume (get larger),
Contract- decrease in volume (get smaller)

51. #1 #2
Bridges are made from materials that contract and expand as the temperature changes, so they cannot be fastened firmly to the bank of a river or lake.
The photographs below show an expansion joint at the end of a bridge in winter and in summer.
Which season is shown in each picture? Explain how you know.
(b) Why do you suppose concrete roadways and sidewalks are laid in sections with grooves between them?

52. Expansion and Contraction in Gases#1 #2
If you put gases in a flexible container such as a balloon, you can see that they expand and contract much more than solids when the temperature changes.

53. Expansion and Contraction of Liquid
As the thermometer liquid moves up the glass tubing (the bore), it takes up more space. In other words, the liquid expands as it warms. As the thermometer cools, the liquid contracts, so it moves back down the tubing. The liquid must be contracting as it cools. Exception Water doesn’t expanded or contract.