P1.1.4 Heating and Insulating Buildings Mr D Powell.

P1.1.4 Heating and Insulating Buildings

P1 PHYSICSMr D Powell

Mr Powell 2012Index

Connection

• Connect your learning to the content of the lesson

• Share the process by which the learning will actually take place

• Explore the outcomes of the learning, emphasising why this will be beneficial for the learner

Demonstration

• Use formative feedback – Assessment for Learning

• Vary the groupings within the classroom for the purpose of learning – individual; pair; group/team; friendship; teacher selected; single sex; mixed sex

• Offer different ways for the students to demonstrate their understanding

• Allow the students to “show off” their learning

Activation

• Construct problem-solving challenges for the students

• Use a multi-sensory approach – VAK• Promote a language of learning to

enable the students to talk about their progress or obstacles to it

• Learning as an active process, so the students aren’t passive receptors

Consolidation

• Structure active reflection on the lesson content and the process of learning

• Seek transfer between “subjects”• Review the learning from this lesson and

preview the learning for the next• Promote ways in which the students will

remember• A “news broadcast” approach to learning

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Quick Summary....

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P1.1.4 Heating and Insulating Buildingsa) U-values measure how effective a material is as an insulator.

b) The lower the U-value, the better the materialis as an insulator.

c) Solar panels may contain water that is heated by radiation from the Sun. This water may then be used to heat buildings or provide domestic hot water.

d) The specific heat capacity of a substance is theamount of energy required to change thetemperature of one kilogram of the substanceby one degree Celsius.

E = mc

E is energy transferred in joules, Jm is mass in kilograms, kg is temperature change in degrees Celsius, °Cc is specific heat capacity in J / kg °C

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Insulation

We can insulate our homes to keep the energy in.

Different forms of insulation save us different amounts of money as they save different amounts of energy

A

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This is usually used when installing an under floor heating system. This consists of;

carpet, ceramic tile, etc) screed water pipe floor insulation concrete sub-floor

Floor Insulation A

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Cavity Wall Insulation II

This insulation is in the form of polystyrene beads. This allows the house to breathe more freely than with the Glassroc

A

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This is a very modern form of cavity wall. The Glassroc is made from glass fibres matted together and prevents convection currents

Cavity Wall Insulation A

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These brush like structures prevent convection currents around doors and are very cheap to fit.

Draught Excluders

They also come in a rubber seal form to go around windows

A

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Double Glazing

Two glass sheets of glass create a sandwich of trapped air.

This prevents conduction and convection currents.

Often one surface has a special coating to absorb the suns infra red rays.

A

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Learning point a) & b) U - Values

This is a measure of the thermal (heat) energy flowing through a building element. The higher the U-value, the more heat flows through, so a good U-value is a low one.

The U-VALUE physically describes how much thermal energy in watts (W) is transferred through a building component with an area of 1m2 at a temperature difference of 1°C. The units for U value are.... Wm-2 °C

A

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U-Value Material Types...

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c) Solar Water Panels

Solar heating panels absorb infrared radiation and use it to heat water. The panels are placed to receive the maximum amount of the Sun’s energy. In the northern hemisphere, they must face south and be angled so that the Sun’s rays falls on them as directly as possible for as long as possible.

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d) The specific heat capacity

The specific heat capacity of a substance is the amount of energy required to change the temperature of one kilogram of the substance by one degree Celsius.

E = m c

E is energy transferred in joules, Jm is mass in kilograms, kg is temperature change in degrees Celsius, °Cc is specific heat capacity in J / kg °C

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Question 2

How can you explain these things...

P1.1.4 Heating and Insulating Buildings

a) U-values measure how effective a material is as an insulator.

b) The lower the U-value, the better the material is as an insulator.

c) Solar panels may contain water that is heated by radiation from the Sun. This water may then be used to heat buildings or provide domestic hot water.

d) The specific heat capacity of a substance is the amount of energy required to change the temperature of one kilogram of the substanceby one degree Celsius.

E = m c

C

What do they do?

P1.1.4 Heating and Insulating Buildings

2) The same amount of heat was supplied to different masses of three substances: A, B and C. The temperature rise in each case is shown in the table below. Calculate the specific heat capacities of A, B and C. (FT)

A)

B)

C)

Specific Heat Capacity Questions...

4) A microwave oven is used to heat a cold mug of coffee. In a few seconds the temperature of the coffee rises by 70 °C. Showing clearly how you work out your final answer, calculate the heat energy in joules gained by the coffee. Take the mass of the coffee to be 0.2 kg and the specific heat capacity of the coffee to be 4000 J/kg °C. (HT)

3) The table shows how much energy is needed to make the temperature of 1 kg of Different substances rise by 1 °C. Which substance has the highest specific heat capacity? Give a reason for your answer. (FT/HT)

1) Calculate the amount of heat energy which must be supplied to heat 5 kg of water in a bath from 15 °C to 68 °C. Given that the specific heat capacity of water is 4200 J/kg °C. (FT)

P1.1.4 Heating and Insulating Buildings