WORKSHEETS

Question 1

Explain how an inflatable lifebuoy can be made to float

Answer 1

An inflatable lifebuoy floats because when submerged, it rapidly inflates, creating an air-filled chamber within the fabric, the mass stays constant and density decreases, the overall volume increases.

Question 2

Explain why a cargo ship sinks when it is loaded with too much cargo

Answer 2

The excess weight increases its overall density to be greater than the water it displaces, exceeding the ship’s buoyancy

Question 3

Explain what happens when water in a pot is heated up. State the type of heat transfer.

Answer 3

Convection occurs. When temperature increase, water particles move faster, water expand, density decreases, and the particles rise up. Cold particles sink down. This circulates the heat energy in the water. Conduction happens between the water and the pot. When particles move faster, they collide with neighbouring particles causing them to move faster and transfer energy

Question 4

Explain how evaporation causes cooling

Answer 4

Higher energy and faster particles are able to escape from the liquid. When these particles escape, the average particle speed of the liquid decreases, therefore, the temperature decreases

Question 5

A pot of boiling soup was left on the table at room temperature. Explain what happens to the temperature of the hot soup using understanding of the three types of heat transfer

Answer 5

Heat is lost via conduction when heat energy is conducted through the pot to the table. Heat is lost via convection when heat energy is transferred from the surface of the soup to the air above it. Heat is lost via radiation when heat is emitted/transmitted to the surroundings

Question 6

Ice was placed inside two containers, A and B that were made from different materials. The ice inside Container A melted before the ice inside Container B. Deduce the type of material Container A was made of. Explain your answer

Answer 6

Container A was made of a conductor because heat can conduct into the container through its walls much faster. Container B is made of an insulator

Question 7

Heat radiation can be…

Answer 7

Transmitted, absorbed, and reflected

Question 8

Explain why double-glazed windows are effective at preventing heat transfer

Answer 8

Trapped air in between the 2 pieces of glass prevents conduction and reduces convection

Question 9

State the conditions that allow destructive interference to happen

Answer 9

1. They must have the same wavelength
2. They are not in phase/step

Question 10

Define audible range

Answer 10

The range of frequency of sounds that can be heard

Question 11

State the range of the human audible range

Answer 11

20Hz to 20000Hz

Question 12

What is the name for sounds with frequencies above the upper limit of the human audible range?

Answer 12

Ultrasound

Question 13

State an example of the use of ultrasound

Answer 13

Medical ultrasound imaging
Sonar

Question 14

Define noise

Answer 14

Unwanted sound

Question 15

Explain the two criteria needed for risk assessment

Answer 15

Probability: How likely something bad will happen
Consequence: How serious the consequence could be if the hazard occurs

Question 16

Explain the three methods to reduce risk of hearing damage

Answer 16

1. Use shielding
2. Increasing distance from the source of sound
3. Reduce the duration exposed to the sound

Question 17

The law of conservation of energy states that energy…

Answer 17

Cannot be created or destroyed

Question 18

Define current

Answer 18

Rate of flow of charge

Question 19

Define voltage

Answer 19

Energy transferred per charge

Question 20

Given a series circuit consisting of 1 battery and 2 identical lightbulbs. A student would like to measure the voltage and current of 1 lightbulb. Describe how should the student connect the instruments to measure the required current and voltage.

Answer 20

Voltmeter to measure the voltage is connected in parallel/across to the lightbulb. Ammeter to measure current is connected in series to/beside the lightbulb

Question 21

In a series circuit consisting of 2 lightbulbs, a resistor was added in series to the lightbulbs. Describe what happens to the brightness of the lightbulbs

Answer 21

Brightness of both bulbs decreases. Total resistance has increased, current through and voltage across both bulbs decreases.

Question 22

In a parallel circuit consisting of 2 lightbulbs in parallel, describe what happens when a resistor was added in series to 1 lightbulb. Describe what happens to the brightness of both lightbulbs.

Answer 22

Brightness of the bulb connected in series will decrease. Because resistance in that loop is increased, current and voltage for that lightbulb decreased. Brightness of lightbulb in parallel will not change because no charge in resistance of that loop

Question 23

In a parallel circuit consisting of 2 lightbulbs in parallel, describe what happens when a resistor was added in parallel to the lightbulbs. Describe what happens to the brightness of both lightbulbs.

Answer 23

Brightness does not change. Total resistance decreases and total current increases but resistances across each branch is uncharged, so current also uncharged

Question 24

State the definition of power and its unit

Answer 24

Power is amount of energy transferred per unit time, its unit is J/s or Watt (W)

Question 25

State 2 evidence for Big Bang Theory

Answer 25

1. Galaxies are moving further away from each other 2. Galaxies that are further away move faster

Question 26

Describe how the Universe is formed using the Big Bang Theory

Answer 26

The Universe originated and expanded from something unimaginably hot and small. From that tiny point, the Universe grew into the size of a galaxy in a fraction of a second. The expansion is still continuing. The more it expands, the cooler it is.

Question 27

State 2 possible ways the Universe will end based on Big Bang Theory

Answer 27

1. Expand forever 2. Expand until a certain point and then it'll stop

Question 28

Explain how a large asteroid impact causes an impact winter and the subsequent mass extinction event

Answer 28

A large asteroid impact will throw out large amount of dust and debris into the atmosphere. The dust and debris will then cause blocking out of the sunlight and cooling the Earth. This is called impact winter. When this condition continues, plants do not get enough sunlight for photosynthesis and will die in large number, leading to shortage of food for herbivores which will die then carnivores

Question 29

State and explain briefly three hypotheses and the formation of the moon. State one evidence supporting and one evidence against each theory.

Answer 29

1. Giant impact hypothesis Evidence for: Earth has an iron core, composition of Earth and Moon are similar, Moon is spherical, orbit of Moon aligns as predicted Evidence against: -- 2. Co-formation theory Evidence for: Composition of Earth and Moon are similar, Moon is spherical Evidence against: Earth has iron core while Moon does not 3. Capture theory Evidence for: Density of Earth is much greater Evidence against: Moon is spherical

Question 30

All nebulae make stars. True or false?

Answer 30

False, not all nebulae make stars, only some (stellar nurseries)

Question 31

Nuclear fusion occurs in protostars. True or false?

Answer 31

False, nuclear fusion occur in main-sequence star

Question 32

Nuclear fusion fuses hydrogen to make helium. True or false?

Answer 32

True

Question 33

Elements heavier than iron are made in stars. True or false?

Answer 33

False, elements heavier than iron are made in supernova

Question 34

A red giant will undergo supernova in the next stage of its lifecycle. True or false?

Answer 34

False, a red super giant will undergo supernova in the next stage of its lifecycle

Question 35

Our Sun is a red giant star. True or false?

Answer 35

False, our Sun is a main-sequence star.