6th Grade Science Quiz Questions And Answers

A metal spoon is magnetic because it is made of a material that contains iron, such as stainless steel or cast iron. These materials have magnetic properties and can be attracted to magnets. On the other hand, socks and a wooden spoon do not have magnetic properties as they are made of non-magnetic materials like fabric and wood.

The Sun, an electric lamp, and a candle are all light sources. The Sun emits light and heat naturally, making it the primary source of light during the day. Electric lamps are man-made light sources that use electricity to produce light. Candles produce light through combustion, where the heat from the flame causes the wax to melt and release energy in the form of light.

To be able to see a microorganism, you need a microscope. A microscope is a scientific instrument that magnifies small objects, allowing us to see them in detail. Unlike a telescope or binoculars, which are used to observe distant objects, a microscope is specifically designed for viewing tiny organisms such as bacteria, viruses, and other microscopic life forms. It uses a combination of lenses and light to magnify the specimen, making it visible to the human eye.

Evaporation is the process where a liquid changes into a gas. This happens when the molecules in a liquid gain enough energy to break free from their bonds and escape into the air as gas molecules. Think of a puddle drying up in the sun – the water evaporates into the air.

The Moon is not a light source because it does not produce its own light. Unlike the Sun and a candle, which emit light, the Moon only reflects the sunlight that it receives from the Sun. Therefore, it is not considered a light source itself.

 A shiny surface would be most suited to reflecting light because it has a smooth and polished texture that allows light to bounce off it easily. The smoothness of the surface reduces the scattering of light, resulting in a higher degree of reflection. In contrast, a dull surface has a rough texture that causes light to scatter in different directions, reducing the overall reflection. A scrubbed surface may have some reflective properties depending on its smoothness, but it would not be as effective as a shiny surface. An opaque surface, by definition, does not allow light to pass through it, so it would not reflect light effectively.

The statement "All microorganisms are bad" is a generalization and is not true. While some microorganisms can cause diseases and harm to humans, not all microorganisms are bad. In fact, many microorganisms are essential for various ecological processes and some are even beneficial to humans, such as the ones used in fermentation, production of antibiotics, and digestion. 

Conjugation is the primary mechanism by which antibiotic resistance is transferred between bacteria. It involves the direct transfer of genetic material (plasmids or chromosomal DNA) from one bacterium to another through a sex pilus. While mutation, transformation, and transduction also play roles in genetic variation, conjugation is the most important method for the spread of antibiotic resistance in bacterial populations.

Microorganisms can cause disease by infecting and harming the human body, leading to illnesses and infections. Additionally, they can also make bread go mouldy by breaking down the carbohydrates in bread, causing it to spoil and develop mould.

Not keeping food in the fridge can lead to food spoilage and the growth of harmful bacteria. Refrigeration helps to slow down the growth of bacteria and prevents food from spoiling quickly. It is important to store perishable foods such as meat, dairy products, and leftovers in the refrigerator to maintain their freshness and prevent foodborne illnesses.

The circulatory system, which includes the heart, blood vessels, and blood, is responsible for transporting oxygen, nutrients, and hormones to the body's cells. It also carries away waste products like carbon dioxide. Think of it as the body's "delivery system."

Air resistance is the force that slows down a man falling out of a plane with a parachute. When an object moves through the air, the air molecules push against it, creating a resistance force. This force opposes the motion of the object and causes it to slow down. In the case of a person falling with a parachute, the large surface area of the parachute increases the air resistance, allowing the person to descend at a slower rate. Without air resistance, the person would fall much faster and potentially be injured upon landing.

A simple machine is a basic mechanical device that changes the direction or magnitude of a force. The six classical simple machines are the lever, wheel and axle, pulley, inclined plane, wedge, and screw. A pendulum, while a useful tool for demonstrating concepts like gravity and motion, is not a simple machine.

Microorganisms, specifically bacteria and fungi, play a crucial role in the production of cheese, yogurt, and bread. In the case of cheese, bacteria are responsible for converting lactose into lactic acid, which helps in curdling the milk and forming cheese. Yogurt is made by the fermentation of milk by bacteria, which produce lactic acid and give yogurt its characteristic tangy flavor. Similarly, bread is made through the process of fermentation, where yeast, a type of fungus, converts sugars into carbon dioxide gas, causing the dough to rise and giving bread its fluffy texture. 

Tides are the rise and fall of sea levels caused by the combined gravitational forces exerted by the Moon and the Sun on the Earth. The Moon's gravity pulls the water on the side of the Earth closest to it, creating a bulge (high tide). A corresponding bulge occurs on the opposite side of the Earth.

A chemical change is a process where a new substance is formed with different properties. When paper burns, it reacts with oxygen in the air, producing ash, smoke, and gases. These new substances have different properties than the original paper.

Gravity and upthrust are the two forces that are balanced and prevent a boat from sinking. Gravity pulls the boat downwards, while upthrust, also known as buoyant force, pushes the boat upwards. When these two forces are equal, the boat remains afloat and does not sink.