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1/20
What unusual thing happens to water when it freezes?
What unusual thing happens to water when it freezes?
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It expandsIt becomes heavierIt shrinksIt sinksPoints Won
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Most liquids have a quite simple behavior when they are cooled (at a fixed pressure): they shrink. The liquid contracts as it is cooled; because the molecules are moving slower, they are less able to overcome the attractive intermolecular forces, drawing them closer to each other. Then, the freezing temperature is reached and the substance solidifies, which causes it to contract some more because crystalline solids are usually tightly packed. Water is one of the few exceptions to this behavior. When liquid water is cooled, it contracts like one would expect until a temperature of approximately 4 degrees Celsius is reached. After that, it expands slightly until it reaches the freezing point, and when it freezes, it expands by approximately 9%.
Source: IAWPS
2/20
In electricity, what is the meaning of "AC"?
In electricity, what is the meaning of "AC"?
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Alternating currentActive currentAsynchronous communicationsAir conditioningPoints Won
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Alternating current (AC) is an electric current that periodically reverses direction and changes its magnitude continuously with time in contrast to direct current (DC) which flows only in one direction. Alternating current is the form in which electric power is delivered to businesses and residences, and it is the form of electrical energy that consumers typically use when they plug kitchen appliances, televisions, fans, and electric lamps into a wall socket.
Source: Wikipedia
3/20
How does an air fryer cook food?
How does an air fryer cook food?
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Direct fireHot airCold airHot oilPoints Won
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Air fryers don't actually fry. Instead, the food goes into a perforated basket, and the machine cooks it by blowing hot air around it. The force of the air produces a convection effect that cooks and browns the exterior of the food in the basket. As long as the air temperature reaches more than 320 F, breaded foods like frozen chicken tenders or unbreaded starchy items like french fries or tater tots will, in fact, turn brown.
Source: The Spruce Eats
4/20
What happens to air pressure near a tornado?
What happens to air pressure near a tornado?
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It risesIt dropsIt depends on the typeNothingPoints Won
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It drops. The air pressure will drop considerably near a tornado. Many people near a tornado tell of their ears "popping" due to the pressure change. There is a popular myth that low pressure with a tornado causes buildings to "explode" as the tornado passes overhead, however, it is the force of the horizontal wind and debris slamming into buildings that causes structural damage during a tornado. It is not the pressure change.
Source: National Weather Service
5/20
How is hydropower generated?
How is hydropower generated?
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WindSunPlasticWaterPoints Won
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Hydropower, or hydroelectric power, is one of the oldest and largest renewable energy sources, which uses the natural flow of moving water to generate electricity. Hydropower currently accounts for 37% of total U.S. renewable electricity generation and about 7% of total U.S. electricity generation. While most people might associate the energy source with the Hoover Dam—a huge facility harnessing the power of an entire river behind its wall—hydropower facilities come in all sizes. Some may be very large, but they can be tiny, too, taking advantage of water flows in municipal water facilities or irrigation ditches.
Source: Energy
6/20
What does the endocrine system produce?
What does the endocrine system produce?
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AntibioticsRed Blood CellsHormonesProteinPoints Won
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The endocrine system is a messenger system comprising feedback loops of the hormones released by the internal glands of an organism directly into the circulatory system, regulating distant target organs. In vertebrates, the hypothalamus is the neural control center for all endocrine systems. In humans, the major endocrine glands are the thyroid gland and the adrenal glands. The study of the endocrine system and its disorders is known as endocrinology.
Source: Wikipedia
7/20
How do electric cars power their engines?
How do electric cars power their engines?
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Fossil fuelBattery packGasHydrogenPoints Won
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All-electric vehicles, also referred to as battery electric vehicles (BEVs), have an electric motor instead of an internal combustion engine. The vehicle uses a large traction battery pack to power the electric motor and must be plugged into a wall outlet or charging equipment, also called electric vehicle supply equipment (EVSE). Because it runs on electricity, the vehicle emits no exhaust from a tailpipe and does not contain the typical liquid fuel components, such as a fuel pump, fuel line, or fuel tank.
Source: US Department of Energy
8/20
When a plant photosynthesizes, where is it getting its energy from?
When a plant photosynthesizes, where is it getting its energy from?
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SoilWaterInsectsSunPoints Won
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Photosynthetic plants synthesize carbon-based energy molecules from the energy in sunlight. Consequently, they provide an abundance of energy for other organisms. Most living things depend on photosynthetic cells to manufacture the complex organic molecules they require as a source of energy. Photosynthetic cells are quite diverse and include cells found in green plants, phytoplankton, and cyanobacteria. During the process of photosynthesis, cells use carbon dioxide and energy from the sun to make sugar molecules and oxygen.
Source: Nature.com
9/20
What causes clouds to become rain?
What causes clouds to become rain?
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Wind speedAltitudeCondensationEvaporationPoints Won
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Condensation is the process of gaseous water (water vapor) turning into liquid water. The clouds floating overhead contain water vapor and cloud droplets, which are small drops of condensed water. These droplets are way too small to fall as precipitation, but they are large enough to form visible clouds. Water is continually evaporating and condensing in the sky. As water droplets combine with each other (also known as coalescence), and grow, clouds not only develop, but precipitation may also occur.
Source: United States Geological Survey
10/20
What happens when a wildfire creates its own wind system?
What happens when a wildfire creates its own wind system?
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A firestormLightningThe fire goes outIt attracts rain cloudsPoints Won
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A firestorm is a conflagration that attains such intensity that it creates and sustains its own wind system. It is most commonly a natural phenomenon, created during some of the largest bushfires and wildfires. Although the term has been used to describe certain large fires, the phenomenon's determining characteristic is a fire with its own storm-force winds from every point of the compass towards the storm's center, where the air is heated and then ascends.
Source: Wikipedia
11/20
How do anglerfish catch their prey?
How do anglerfish catch their prey?
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With special pheromonesWith a lureMaking soundsWhile they are asleepPoints Won
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Anglerfish have perfected the art of deep-sea fishing. Although different species vary in size and shape, they all catch their prey with a lure like appendage. Once an unsuspecting prey swims too close, the anglerfish snaps it up. Instead of expending energy to hunt their prey, deep-sea anglerfish have developed a fishing pole-like rod that projects from their head. At the end of the rod is a sac of bioluminescent bacteria that glows brightly in the dark. The light attracts prey toward the anglerfish’s waiting mouth.
Source: Monterey Bay Aquarium
12/20
What does the bobbin do in a sewing machine?
What does the bobbin do in a sewing machine?
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Mends broken threadsHolds the lower threadCreates sewing patternsAligns the seamsPoints Won
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A bobbin is a small plastic or metal spool that contains thread and is placed in the lower part of the sewing machine. The bobbin holds the lower thread of the machine. Each stitch is made by catching the bottom thread from the bobbin with the top thread that comes through the needle. The bobbin thread and the top spool of thread need to be of the same quality to ensure correct tension and neat stitching. Ideally, they should be the same color also, but this is not strictly necessary. Keeping a good supply of bobbins just makes sewing easier.
Source: Treasurie
13/20
What does a cartomancer use to predict the future?
What does a cartomancer use to predict the future?
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BooksMelted WaxRunesCardsPoints Won
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Cartomancy is fortune-telling or divination using a deck of cards. Forms of cartomancy appeared soon after playing cards were first introduced into Europe in the 14th century. Practitioners of cartomancy are generally known as cartomancers, card readers, or simply readers. Cartomancy using standard playing cards was the most popular form of providing fortune-telling card readings in the 18th, 19th, and 20th centuries.
Source: Wikipedia
14/20
What does Boyle's Law describe?
What does Boyle's Law describe?
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Behavior of liquidBehavior of electronsBehavior of chemicalsBehavior of gasPoints Won
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Boyle’s Law is a basic law in chemistry describing the behavior of gas held at a constant temperature. The law, discovered by Robert A. Boyle in 1662, states that at a fixed temperature, the volume of gas is inversely proportional to the pressure exerted by the gas. In other words, when a gas is pumped into an enclosed space, it will shrink to fit into that space, but the pressure that gas puts on the container will increase.
Source: Clippard
15/20
Which process causes heat to be trapped in Earth's atmosphere?
Which process causes heat to be trapped in Earth's atmosphere?
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Kitchen EffectAttic EffectCellar EffectGreenhouse EffectPoints Won
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The greenhouse effect is a process that occurs when gases in Earth's atmosphere trap the Sun's heat. This process makes Earth much warmer than it would be without an atmosphere. The greenhouse effect is one of the things that makes Earth a comfortable place to live. As you might expect from the name, the greenhouse effect works … like a greenhouse! A greenhouse is a building with glass walls and a glass roof. Greenhouses are used to grow plants, such as tomatoes and tropical flowers.
Source: NASA
16/20
What happens to water's boiling point as altitude increases?
What happens to water's boiling point as altitude increases?
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It increasesIt stays the sameIt decreasesIt varies randomlyPoints Won
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As altitude increases, the boiling point of water changes: it decreases. The reason is the lower atmospheric pressure due to a thinner blanket of air above. As atmospheric pressure decreases, water boils at lower temperatures. At sea level, water boils at 212 °F. With each 500-feet increase in elevation, the boiling point of water is lowered by just under 1 °F. At 7,500 feet, for example, water boils at about 198 °F. Because water boils at a lower temperature at higher elevations, foods that are prepared by boiling or simmering will cook at a lower temperature, and it will take longer to cook.
17/20
What is the process of removing dead skin cells from the body called?
What is the process of removing dead skin cells from the body called?
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ExfoliationWaxingLubridermElectrolysisPoints Won
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Exfoliation is the process of removing dead skin cells with a substance or tool known as an exfoliator. Exfoliators come in many forms, from chemical treatments to brushes. Before choosing an exfoliator, it’s important to know what type of skin you have. Keep in mind that your skin type can change with age, weather changes, and lifestyle factors, such as smoking.
Source: Health Line
18/20
What effect does adding "lime" have on soil?
What effect does adding "lime" have on soil?
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Prevents erosionNeutralizes acidImproves drainageNonePoints Won
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In many parts of the country, adding lime to your lawn is as essential as mowing it. Without lime, lawn grasses may be unable to benefit from the nutrients in your soil, including those you add through fertilizers. Adding lime to soil neutralizes acid, which can improve the availability of plant nutrients. Lime is a soil amendment made from ground limestone rock, which naturally contains calcium carbonate and magnesium carbonate. When lime is added to soil, these compounds work to increase the soil's pH, making the soil less acidic and more alkaline. Even though lime includes calcium and magnesium, which are essential nutrients for healthy plant growth, it's not a substitute for fertilizer.
Source: Pennington
19/20
What purpose does chalk serve while climbing?
What purpose does chalk serve while climbing?
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Repel spidersAvoid rope burnsDry sweatMark the pathPoints Won
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Climbers use chalk to dry sweat and other moisture on their hands, increasing friction and improving their grip on the holds. Most climbing chalk you’ll find is made from Magnesium Carbonate. This is the same compound that gymnasts, weightlifters, and other athletes will put on their hands in order to improve friction and grip. Though it is sometimes available in other colors, it’s usually white. Climbing chalk commonly comes in a few different forms: block, loose, or liquid. Which one you use is a matter of personal preference.
Source: Friction Labs
20/20
What is the function of a spark plug in an internal combustion engine?
What is the function of a spark plug in an internal combustion engine?
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Regulate fuel flowIgnite the fuelConvert motion to electricityStop oil leaksPoints Won
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A spark plug is an electrical device used in an internal combustion engine to produce a spark and ignite the fuel-air mixture in the combustion chamber. As part of the engine's ignition system, the spark plug receives high-voltage electricity (generated by an ignition coil in modern engines and transmitted via a spark plug wire) which it uses to generate a spark in the small gap between the positive and negative electrodes. The timing of the spark is a key factor in the engine's behavior, and the spark plug usually operates shortly before the combustion stroke commences. The spark plug was invented in 1860, however, its use only became widespread after the invention of the ignition magneto in 1902. Diesel engines use compression ignition (instead of spark ignition), therefore they do not normally use spark plugs.
Source: Wikipedia
