SENIOR PHASE HEADSTART NATURAL
SCIENCES OUP SA
Headstart Natural Sciences offers a simple step-by-step approach to Natural Sciences. It provides a solid foundation to guide learners through the Senior Phase with: step-by-step activities to guide learners through investigations and experiments
additional language support, including a focus on exam words, new
detailed teaching tips activity guidelines step-by-step planning assessment tools a free resource CD, packed with useful teacher resources (Grade 8 and 9).
GRADE 7 Learner’s Book
Teacher’s Guide
GRADE 8 Learner’s Book
Teacher’s Guide
GRADE 9 Learner’s Book
Teacher’s Guide
978 0 19 905792 4 978 0 19 904991 2
978 0 19 905495 4 978 0 19 905054 3
978 0 19 904279 1 978 0 19 599831 3
Natural Sciences CORE CLASSROOM COURSE
Headstart Natural Sciences Grade 7 Learner’s Book Secondary Catalogue 23
SENIOR PHASE
4. Draw the pipe going from the collection tank to the holding tank and the tap on the holding tank.
5. Show the convection currents in the collection tank by means of arrows.
Insulating materials
Materials that do not allow heat energy to move through them are called non-conductors or insulators. Insulators can keep heat in or they can keep heat out. Tey are useful to prevent unwanted heat loss or prevent unwanted heat gain.
P Practical activity 1
Investigating insulating materials to prevent heat loss
Aim: In this practical activity you will investigate how well materials prevent heat from being lost.
You will need: • • • • •
• p •
St St
S
Ste St
Step S
Step 3 Step 4
Step 4 Record the temperatures in a results table. Read the temperatures at the start, and then every 15 minutes for one hour.
tep te
ep insulator non-conductor of heat 152 9780199057924_HS_ S_07_ .indb 152
Meth Step 1 tep 2 te
Step 2 Step 3
ethod: Stand the tins in the boxes.
Surround each tin with one of the insulating materials. Fill the tins half-way with hot water from the same container. Te water in the tins must be at the same temperature.
three metal tins
three small cardboard boxes large enough to hold a tin three thermometers Styrofoam
crumpled newspaper
plastic (any used plastic bags or refuse bin bags) a watch with a second hand or a stopwatch.
Heat can be gained through conduction, convection and radiation
When we stand in the Sun we absorb heat and feel warm. Te heat from the Sun can be used for other purposes, such as heating water.
Figure 1 An electric geyser How does a simple solar water heater work?
Look at the labelled diagram of the simple solar water heater to see how it works. Sun
radiation waves
collector sheet
collection tank Figure 2 A diagram of a simple solar heater Activity 1 Drawing, labeling and explaining
1. Read all the instructions before you start. 2. Copy the solar heater illustrated above. Leave space around the sketch to add labels.
3. Label the following parts: heat collector, collection tank, holding tank. solar from the Sun 151 2013/07/30 04:14:06
holding tank
Collector sheet absorbs radiant heat from the sun. It then passes on the heat to the water in the collection tank by conduction. Convection currents occur in the water in the collection tank. Hot water rises and moves to the holding tank. Water moves from the top of the tank to the bottom as it cools. Hot water moves from the tank to the house. Colder water moves to the collection tank. Cold water input to replace water used in the house.
Strand 3
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