Experiment 6.2:
Problem statement: What are the differences between metals and non-metals?
Aim: To study the characteristics of metals and non-metals
(I) Appearance of metals and non-metals
Hypothesis: Metals have a shiny surface
Variables
Manipulated variable: Type of material
Responding variable: The appearance of the material
Constant variable: Size of material
Materials and apparatus: Copper rod, carbon rod, sandpaper.
Procedure
1. Rub the surface of a copper rod and carbon rod with sandpaper (Figure 6.11).
2. Observe the appearance of the copper rod and carbon rod surface.
3. Record your observation.
Problem statement: What are the differences between metals and non-metals?
Aim: To study the characteristics of metals and non-metals
(I) Appearance of metals and non-metals
Hypothesis: Metals have a shiny surface
Variables
Manipulated variable: Type of material
Responding variable: The appearance of the material
Constant variable: Size of material
Materials and apparatus: Copper rod, carbon rod, sandpaper.
Procedure
1. Rub the surface of a copper rod and carbon rod with sandpaper (Figure 6.11).
2. Observe the appearance of the copper rod and carbon rod surface.
3. Record your observation.
(II) Ductility:
Hypothesis: Metals are ductile.
Variables
Manipulated variable: Type of material
Responding variable: The ductility of material
Constant variable: Size of material
Materials and apparatus: Copper wire, pencil lead.
Procedure
1. Bend a copper wire to form a circle (Figure 6.12).
2. Repeat step 1 with a pencil lead (Figure 6.13).
3. Record your observation.
Hypothesis: Metals are ductile.
Variables
Manipulated variable: Type of material
Responding variable: The ductility of material
Constant variable: Size of material
Materials and apparatus: Copper wire, pencil lead.
Procedure
1. Bend a copper wire to form a circle (Figure 6.12).
2. Repeat step 1 with a pencil lead (Figure 6.13).
3. Record your observation.
(III) Malleability:
Hypothesis: Metals are malleable.
Variables
Manipulated variable: Type of material
Responding variable: The malleability of material
Constant variable: Size of material
Materials and apparatus : Iron piece, copper piece, sulphur piece, hammer, wooden block.
Procedure
1. Knock an iron piece on a wooden block using a hammer several times (Figure 6.14).
2. Observe the changes in the shape of the iron piece.
3. Repeat steps 1 and 2 using the copper and sulphur piece.
4. Record your observation.
Hypothesis: Metals are malleable.
Variables
Manipulated variable: Type of material
Responding variable: The malleability of material
Constant variable: Size of material
Materials and apparatus : Iron piece, copper piece, sulphur piece, hammer, wooden block.
Procedure
1. Knock an iron piece on a wooden block using a hammer several times (Figure 6.14).
2. Observe the changes in the shape of the iron piece.
3. Repeat steps 1 and 2 using the copper and sulphur piece.
4. Record your observation.
(IV) Electrical conductivity:
Hypothesis: Metals conduct electricity.
Variables
Manipulated variable: Type of material
Responding variable: The deflection of the ammeter’s needle
Constant variable: Size of material
Materials and apparatus: Dry cell, ammeter, crocodile clips, iron rod, carbon rod, sulphur rod.
Procedure
1. Set up the apparatus as shown in Figure 6.15.
2. Connect the ends of an iron rod with crocodile clips.
3. Observe the deflection of the ammeter’s needle.
4. Repeat steps 2 and 3 by replacing the iron rod with carbon rod and sulphur rod.
5. Record your observation.
Hypothesis: Metals conduct electricity.
Variables
Manipulated variable: Type of material
Responding variable: The deflection of the ammeter’s needle
Constant variable: Size of material
Materials and apparatus: Dry cell, ammeter, crocodile clips, iron rod, carbon rod, sulphur rod.
Procedure
1. Set up the apparatus as shown in Figure 6.15.
2. Connect the ends of an iron rod with crocodile clips.
3. Observe the deflection of the ammeter’s needle.
4. Repeat steps 2 and 3 by replacing the iron rod with carbon rod and sulphur rod.
5. Record your observation.
(V) Heat conductivity:
Hypothesis: Metals conduct heat.
Variables
Manipulated variable: Type of material
Responding variable: Time taken for the thumbtack to drop
Constant variable: Size of material
Materials and apparatus: Carbon rod, iron rod, copper rod, candle, stopwatch, thumbtack, wax, retort stand with clamp.
Procedure
1. Clamp a carbon rod to the retort stand.
2. Put the thumbtack at the end of the carbon rod.
3. Heat the other end of the carbon rod (Figure 6.16).
4. Observe and record the time taken for the thumbtack to drop.
5. Repeat steps 1-4 by using an iron rod and copper rod.
Hypothesis: Metals conduct heat.
Variables
Manipulated variable: Type of material
Responding variable: Time taken for the thumbtack to drop
Constant variable: Size of material
Materials and apparatus: Carbon rod, iron rod, copper rod, candle, stopwatch, thumbtack, wax, retort stand with clamp.
Procedure
1. Clamp a carbon rod to the retort stand.
2. Put the thumbtack at the end of the carbon rod.
3. Heat the other end of the carbon rod (Figure 6.16).
4. Observe and record the time taken for the thumbtack to drop.
5. Repeat steps 1-4 by using an iron rod and copper rod.
(VI) Melting point:
Hypothesis: The melting point of metals are higher.
Variables
Manipulated variable: Type of materials
Responding variable: Melting point of material
Constant variable: Quantity of materials
Materials and apparatus: Thermometer (0-360°C), crucible, Bunsen burner, pipeclay triangle, tripod stand, tin powder, sulphur powder.
Procedure
1. Heat tin powder in a crucible (Figure 6.17).
2. Observe and record the melting point of the tin powder.
3. Repeat steps 1 and 2 with sulphur powder.
4. Record your observation.
Results
Conclusion:
Are the hypotheses accepted?
Hypothesis: The melting point of metals are higher.
Variables
Manipulated variable: Type of materials
Responding variable: Melting point of material
Constant variable: Quantity of materials
Materials and apparatus: Thermometer (0-360°C), crucible, Bunsen burner, pipeclay triangle, tripod stand, tin powder, sulphur powder.
Procedure
1. Heat tin powder in a crucible (Figure 6.17).
2. Observe and record the melting point of the tin powder.
3. Repeat steps 1 and 2 with sulphur powder.
4. Record your observation.
Results
Conclusion:
Are the hypotheses accepted?
Question:
1. What is the difference between the appearance of copper rod and carbon rod surface?
2. Between copper wire and pencil lead, which one can be bent?
3. Between iron and sulphur pieces, which one is malleable?
4. Which one can conduct electricity – iron, carbon or sulphur?
5. Between iron and carbon rod, which one can conduct heat?
6. Between tin and sulphur powder, which one has a higher melting point?
Answer:
1. The surface of copper rod is shiny while the surface of carbon rod is not shiny.
2. Copper wire can be bent without breaking.
3. Iron piece is malleable.
4. Iron rod and carbon rod can conduct electricity.
5. Iron rod can conduct heat.
6. Tin powder has a higher melting point.
1. What is the difference between the appearance of copper rod and carbon rod surface?
2. Between copper wire and pencil lead, which one can be bent?
3. Between iron and sulphur pieces, which one is malleable?
4. Which one can conduct electricity – iron, carbon or sulphur?
5. Between iron and carbon rod, which one can conduct heat?
6. Between tin and sulphur powder, which one has a higher melting point?
Answer:
1. The surface of copper rod is shiny while the surface of carbon rod is not shiny.
2. Copper wire can be bent without breaking.
3. Iron piece is malleable.
4. Iron rod and carbon rod can conduct electricity.
5. Iron rod can conduct heat.
6. Tin powder has a higher melting point.