3.2 To discover the properties of materials  (Page 3/3)

_____________________________________________________________________

2. ___________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

ASSIGNMENT 7 (GROUP WORK)

• Now that you have seen how a sea breeze occurs, work out how a land breeze occurs. Sketch what happens and write down your explanation below.

4.3 Radiation:

The transfer of heat from the sun to the earth takes place through radiation.

Heat comes from the sun. Between the sun and the earth's atmosphere there is a vacuum. Heat transfer can't take place through conduction or convection.

Radiated heat from the sun reaches us after it has travelled through the atmosphere. Everything that the sun shines on is heated. However, as we go higher up in the atmosphere it becomes colder.

ASSIGNMENT 8: TO DEMONSTRATE RADIATION

Requirements:

An electric heater

A windowpane

• Switch on an electric heater.
• Hold your hand 30 cm in front of the heater until you feel the heat.
• Put a windowpane between your hand and the heater.

What do you observe?

1. What happened when you put the windowpane in front of the heater?

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

ASSIGNMENT 9: TO DEMONSTRATE RADIATION BY MEANS OF A LIGHT BULB

Requirements: Electric light bulb

Windowpane

4 Hold your hand 5 cm away from the light bulb. Switch it on.

4 When you feel the heat, place the windowpane between your hand and the light bulb.

What do you observe?

1. Does your hand immediately feel the heat?

_____________________________________________________________________

2. How does the heat reach your hand?

_____________________________________________________________________

3. Does the glass interrupt the radiation?

_____________________________________________________________________

What is your conclusion?

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

5. MATERIALS CAN CONDUCT ELECTRICITY

Experiments have proved that the only solids that conduct electricity are metals and graphite. When electricity is conducted, electrons flow through the material but as there is no chemical reaction, no new substances are formed and the weight of the substance remains the same.

Pure water conducts electricity. The ability to conduct electricity increases if an acid is added to the water.

Electricity is a form of energy (like heat). It can be used to heat water and can even cause chemical reactions to take place.

The energy in an electrical current causes water molecules to break up.

It can be summarised like this:

This breaking up of the substance is called electrolysis.

• Open electrical wires are dangerous, especially if there is water nearby. Never touch electrical apparatus with wet hands.

Explain:

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

Assessment

Learning Outcome 1: Learners respond confidently to their desire to learn about natural phenomena; they investigate relationships and solve problems within the context of science, technology and the environment.

Assessment Standard 1.2: We know this when the learner conducts investigations and collects data: conducts simple tests or surveys and records observations or responses.

Assessment

Learning Outcome 1: Learners respond confidently to their desire to learn about natural phenomena; they investigate relationships and solve problems within the context of science, technology and the environment.

Assessment Standard 1.2: We know this when the learner conducts investigations and collects data: conducts simple tests or surveys and records observations or responses.

Learning Outcome 2: Learners know, interpret and apply scientific, technological and environmental knowledge.

Assessment Standard 2.1: We know this when the learner recalls meaningful information: at the minimum, describes the features which distinguish one category of thing from another.

Assessment Standard 2.3: We know this when the learner interprets information: at the minimum, interprets information by using alternative forms of the same information.