Difficult Round Grade 8

Which of the following is TRUE about boiling?

• It is slower than evaporation

• It takes place at a specific temperature

• It is the same for all liquids at the same temperature

• It takes place when bubbles begin to appear in the liquid.

During warm days, you cool yourself by damping your skin with a wet towel. Which of the following takes place?

• Wet towel has no effect on your body

• Wet towel releases heat energy to your body

• Wet towel absorbs heat energy from your body

• Wet towel has the same temperature as your body.

Which of the following is true about the effect of air temperature on the speed of sound?

• The lower the temperature, the faster the speed

• The higher the temperature the faster the speed

• The higher the temperature the slower the speed

• The temperature does not affect the speed of sound

Which is quieter, a room with hanging curtains or one with bare concrete walls? Why?

• Both rooms have the tendency to be peaceful and to be quiet depending on the location

• It is quieter in a room with concrete walls because sound travels faster in a medium with a higher elastic property at the molecular level

• It is quieter in a room with curtains because the bare concrete walls bring about multiple reflections of sound

• It is quieter in a room with bare walls because hanging curtains enhance the effect of sound reverberations.

What information does the Philippine Institute of Volcanology and Seismology (PHIVOLCS) provide?

• monitoring the low-pressure areas in a region in the Philippines

• monitoring of the intertropical Convergence zone (ITCZ)

• monitoring of the earth’s movement and fault lines.

• monitoring of spaces of rocks and debris that are comets and asteroids

Which pair refers to the deformation of two slabs or blocks that tend to push

towards each other?

• Tensional and strike-slip fault

• Compressional and thrust fault

• Compressional and strike-slip fault

• Tensional and normal fault

Which of the following describes the epicenter of an earthquake?

• The location along a fault where the first motion of an earthquake occurs.

• The point on Earth’s surface directly above the focus.

• A seismic wave that travels along the surface of the earth.

• The last place that motion in an earthquake is detected.

Concerts usually take place at night, where everyone can see and enjoy the live show. Why does sound contribute to the concert schedule?

• Sound is more audible at night due to minimal noise.

• Sound propagates faster in air at night than in the daytime

• Sound is heard well in far areas during nighttime than during daytime.

• Sound changes and refracts when it encounters a medium at different density

How does epicenter of an earthquake differ from focus?

• Epicenter is below the earth’s crust while focus is on the surface of the crust.

• The epicenter is the spot where the first motion of an earthquake occurs while

      focus is the spot directly above the epicenter.

• Epicenter is where seismic waves travel along the earth's surface while

      the focus is the last spot in which motion of an earthquake is detected

• The epicenter is the point of the earth’s surface directly above the focus while

      the focus is where a fault begins to slip.

Why Earthquakes are useful for studying Earth’s interior?

• Earthquake produces an array of seismic waves

• Earthquakes are extremely destructive

• Earthquakes happen below the surface of the earth

• Earthquake releases stress that has been stored.