Download HighFour General Sciences Round 8 Category A: Grades 4 – 5

HighFour General Sciences Category A: Grades 4 – 5 Round 8 Wednesday, April 13, 2016 The use of calculator is not allowed. Answer #1: Explanation: Answer #2: Explanation: Answer #3: Explanation: Answer #4: Explanation: Answer #5: Explanation: B The so-­‐called "Planet Nine," as scientists are calling it, is about 10 times the mass of Earth and 5,000 times the mass of Pluto. Here's the order of the planets, starting nearest the sun and working outward through the solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune — and Planet Nine.
A The distance from Earth to the sun is called an astronomical unit, or AU, which is used to measure distances throughout the solar system. The AU has been defined as 149,597,870,700 meters (92,955,807 miles). Astronomers use the AU for measuring distances throughout the solar system.
A Planets in our Solar system size comparison. Largest to smallest are: Jupiter, Saturn, Uranus, Neptune, Earth, Venus, Mars, Mercury.
D Four the planets in the Solar System have rings. They are the four giant gas planets Jupiter, Saturn, Uranus, and Neptune. Saturn, which has by far the largest ring system, was known to have rings for a long time. It was not until the 1970s that rings were discovered around the other gas planets.
C Earth Day is an annual event, celebrated on April 22, on which day events worldwide are held to demonstrate support for environmental protection. It was first celebrated in 1970, and is now coordinated globally by the Earth Day Network, and celebrated in more than 192 countries each year.
HighFour General Sciences Category A: Grades 4 – 5 Round 8 Wednesday, April 13, 2016 The use of calculator is not allowed. Answer #6: Explanation: Answer #7: Explanation: Answer #8: Explanation: Answer #9: Explanation: Answer #10: Explanation: C Venus has the longest day of any planet in our solar system. It completes one rotation every 243 Earth days. Its day lasts longer than its orbit. It orbits the Sun every 224.65 Earth days, so a day is nearly 20 Earth days longer than its year.
A Earth's rotation is the rotation of the planet Earth around its own axis. The Earth rotates from the west towards east. As viewed from North Star or polestar Polaris, the Earth turns counter-­‐clockwise. C For a very short time in 1974, Mercury was thought to have a moon. Venus also has no moons, though reports of a moon around Venus have circulated since the 17th century.
A dB of sound pressure level (dB SPL) is defined as: 20 log10 p1/p0 where p1 is actually measured sound pressure level of a given sound, and p0 is a reference value of 20μPa, which corresponds to the lowest hearing threshold of the young, healthy ear.
D Sound waves need to travel through a medium such as a solid, liquid, or gas. The sound waves move through each of these mediums by vibrating the molecules in the matter. The molecules in solids are packed very tightly.
HighFour General Sciences Category A: Grades 4 – 5 Round 8 Wednesday, April 13, 2016 The use of calculator is not allowed. Answer #11: Explanation: Answer #12: Explanation: Answer #13: Explanation: Answer #14: Explanation: Answer #15: Explanation: A The speed of sound is the distance travelled per unit of time by a sound wave propagating through an elastic medium. In dry air at 20 °C (68 °F), the speed of sound is 343 meters per second (1,125 ft/s).
C A star is a luminous ball of gas, mostly hydrogen and helium, held together by its own gravity. Nuclear fusion reactions in its core support the star against gravity and produce photons and heat, as well as small amounts of heavier elements. The Sun is the closest star to Earth.
B Stars appear to be exclusively white at first glance. But if we look carefully, we can notice a range of colors: blue, white, red, and even gold. In the winter constellation of Orion, a beautiful contrast is seen between the red Betelgeuse at Orion's "armpit" and the blue Bellatrix at the shoulder.
B A galaxy is an enormous collection of gas, dust and billions of stars held together by gravity. One galaxy can have hundreds of billions of stars and be as large as 200,000 light years across.
A The Earth's axis is tilted 23.5 degrees away from the plane of the ecliptic. It's because of this tilt that the Earth experiences seasons as it orbits around the Sun.
HighFour General Sciences Category A: Grades 4 – 5 Round 8 Wednesday, April 13, 2016 The use of calculator is not allowed. Answer #16: Explanation: Answer #17: Explanation: Answer #18: Explanation: Answer #19: Explanation: Answer #20: Explanation: C Biomes are very large ecological areas on the earth's surface, with fauna and flora (animals and plants) adapting to their environment. Biomes are often defined by abiotic factors such as climate, relief, geology, soils and vegetation. A biome is NOT an ecosystem, although in a way it can look like a massive ecosystem.
C Freshwater biomes are large communities of plants and animals centered around water with less than 1% salt concentration. They are very important to survival on Earth. Marine regions cover about three-­‐fourths of the Earth's surface and include oceans, coral reefs, and estuaries. Marine algae supply much of the world's oxygen supply and take in a huge amount of atmospheric carbon dioxide.
D The Amazon biome is considered the most biologically diverse in the world. This biome occupies an area of 4,196,943 square kilometers, which represents more than 40% of the country and consists mainly of rainforest.
B Prairies are ecosystems considered part of the temperate grasslands, savannas, and shrub lands biome by ecologists, based on similar temperate climates, moderate rainfall, and a composition of grasses, herbs, and shrubs, rather than trees, as the dominant vegetation type.
A The tropical rainforest is a hot, moist biome found near Earth's equator. The world's largest tropical rainforests are in South America, Africa, and Southeast Asia. Tropical rainforests receive from 60 to 160 inches of precipitation that is fairly evenly distributed throughout the year.