P1a Heating Houses (Year 9)
- Specification
- Lesson Plans
- Questions
- Resources
- Extras
Recognise that hot objects have high temperatures and tend to cool down.
Recognise that cold objects have low temperatures and tend to warm up.
Recognise that for warm bodies the higher the temperature the quicker they cool.
State that temperature is measured in oC.
State that energy (heat) is measured in J.
Apply knowledge that the energy needed to change the temperature of a body depends on:
- mass;
- the material it is made from;
- the temperature change.
Plan an experiment to measure the energy required to change the temperature of a body.
State that energy is needed to melt or boil things.
Interpret data which shows that there is no temperature change when materials are:
- boiling;
- melting or freezing.
Recognise energy flow from a hot body to a cooler one.
This will cause hotter bodies to cool and cooler bodies to warm.
Recall that temperature is a measurement of hotness.
Recall that heat is a measurement of energy.
Recognise that the specific heat capacity of materials is:
- a measure of how much energy they can hold;
- the energy needed to raise the temperature of 1kg by 1oC;
- different for different materials.
Describe how, even though energy is still being transferred, there is no temperature change when materials are:
- boiling;
- melting or freezing.
Recognise that the specific latent heat of materials is:
- a measure of how much energy is needed to melt or boil them;
- the energy needed to melt or boil 1kg of them;
- different for different materials and states.
Explain that temperature can be represented by a range of colours in a thermogram.
Describe temperature as a measurement of hotness on a chosen scale.
Describe heat as a measurement of energy on an absolute scale.
State and use the equation:
energy = mass x specific heat capacity x temperature change.
(A change of subject may be required).
State and use the equation:
energy = mass x specific latent heat.
(A change of subject may be required.)
Lesson ID:
2010_9_001Starters:
Objectives:
Understand the difference between temperature and heat in terms of a particle description of matter.
Prior Learning:
Particle theory of solids, liquids and gases.
Difficult Concepts:
Temperature as the average kinetic energy per molecule, heat as the total kinetic energy of all the molecules present - potential energy being ignored - links to change of state later on.
Outline:
Really useful to get the class to brain storm ideas about temperature and heat and the difference between the two before you address the scientific explanations of these two terms.
Thermogram in resources section useful to get the idea of a temperature map and begin a discussion about the movement of heat from hot to cold.
Seeing in infra-red links to later work.
Cooling curve for hot water demo or practical. Rate of cooling depends on temperature. Newton's law of cooling for top sets or ambitious teachers. Good graph plotting skills.
Temperature scales activities -
Easy - put a temperature to the situation
More complicated - give the Kelvin temperature and Celcius temperature for a range of situations.
A4 printable copy - temperature cards
Suggested Practicals:
Netwon's law of cooling - kettle, thermometers, boiling tubes and test tube racks and stop watches. Graph paper. Practical advice sheet
Extension Activities:
Rate of cooling depends on temperature. Would need to demo the practical and plot using ICT to allow time for gradient calculations. Plotting gradient of cooling curve against temperature.
Homework:
Fronter homework on temperature
Lesson ID:
2010_9_002Starters:
Questions:
1. Why does it take so long for a kettle to boil?
2. What be the best substance to fill your radiator with air, water or oil?
Objectives:
Understand the physical factors leading to a temperature rise in a given material - specific heat capacity
Prior Learning:
P1a lesson 1 on temperature and heat
Difficult Concepts:
specific heat capacity as a measure of the heatenergy required to heat unit mass of a material by unit temperature rise. Calculating temperature rises using the shc of a material. Rearranging formula.
Outline:
Brainstorm ideas about why it is difficult to raise the temperature of water in a kettle.
Explain specific heat capacity in relation to calculating its value for aluminium.
Explain practical pupils carry it out for aluminium and water at least.
Explain calculation necessary to find shc.
Carry this out in class or for homework.
NOTE: This still leaves latent heat.
Best way to do this is to do a naptha (or similar) cooling curve experiment. This is a good one to do to calm things down as it involves reading the thermometer every minute for about 15 to 20 minutes to get a good result.
Clearly gets across the change of state no change in temperature idea which is a real challenge to many pupils.
Latent Heat calculations will be tested for our internal assessment.
Suggested Practicals:
shc experiment (lesson 2):
shc of aluminium and water. Immersion heaters, stop watches, power supplies (ammeters and voltmeters for the better groups otherwise quote the power of the heater on the board.) thermometers possibly insulating jackets and heat mats. Digital mass balance capable of over 1kg. 250ml beakers for water practical.
Note: risk of burns if the heaters are mis-handled.
Cooling curve experiment (lesson 3):
boiling tubes with thermometers in them and naptha equivalent.
heat bath set to 80 degrees Celcius
test tube racks and heat mats and stop watches and graph paper.
Make sure they put the boiling tubes back in the heat bath for the next class to use with the thermometers in them.
Extension Activities:
Measure shc for other metals.
Homework:
Complete calculations or find true values and explain discrepanices with measured values.