Science Exam PDF

Revision of science 1)what is scientific learning process Ans:This refers to the process of gaining knowledge about natural phenomena through observation, experimentation, and use of scientific method. 2)the different types of scientific learning process Ans: Here’s a breakdown of these steps...

Revision of science 1)what is scientific learning process Ans:This refers to the process of gaining knowledge about natural phenomena through observation, experimentation, and use of scientific method. 2)the different types of scientific learning process Ans: Here’s a breakdown of these steps with definitions: Observation: This is the initial step where you gather information about a phenomenon or problem through your senses or instruments. It involves noticing and recording details about the natural world or a specific occurrence. Question: Based on your observations, you formulate a question or identify a problem that needs to be addressed. This question should be specific, clear, and researchable. Research: Conduct background research to gather existing information related to your question or problem. This includes reviewing scientific literature, previous studies, and theoretical frameworks. Hypothesis: Develop a testable and falsifiable hypothesis. A hypothesis is a proposed explanation or prediction that addresses your question and can be tested through experimentation or observation. Experimentation: Design and conduct experiments or studies to test your hypothesis. This involves setting up controlled conditions, manipulating variables, and collecting data. Ensure that your experimental design allows for reliable and valid results. Data Analysis: Analyze the data collected from your experiments. This step involves using statistical methods and tools to interpret the results, determine patterns, and assess whether the data supports or refutes your hypothesis. Conclusion: Draw conclusions based on your data analysis. Decide whether the results support your hypothesis or if adjustments are needed. This step involves summarizing findings and reflecting on their implications 3) ans;Over time, if the original hypothesis is overwhelmingly supported by the greater scientific community, and if no experiments have proven it wrong, it becomes a theory. 4)ans;The answer to what is SI unit is that it is an abbreviation of the French word Système International. The International System Of Units (SI) is the metric system that is used universally as a standard for measurements. SI units play a vital role in scientific and technological research and development. of metal and non metal 1 and2) ans Properties of Metals: Physical State: Metals are generally solid at room temperature (with mercury being a notable liquid exception). Luster: Metals have a shiny, reflective surface when polished. Malleability: Metals can be hammered or rolled into thin sheets without breaking. This property is called malleability. Ductility: Metals can be drawn into wires. This property is known as ductility. Conductivity: Metals are good conductors of heat and electricity due to the presence of free-moving electrons. Density: Metals typically have high density and are heavy for their size. Melting and Boiling Points: Metals usually have high melting and boiling points. Reactivity: Metals tend to lose electrons and form positive ions in reactions. Their reactivity varies widely (e.g., alkali metals are highly reactive). Properties of Non-Metals: Physical State: Non-metals can be solids, liquids, or gases at room temperature (e.g., sulfur is solid, bromine is liquid, and oxygen is gas). Luster: Non-metals generally lack luster and are not reflective. They tend to be dull. Malleability and Ductility: Non-metals are brittle in solid form and shatter or break easily when hammered. They cannot be drawn into wires. Conductivity: Non-metals are poor conductors of heat and electricity, except for graphite (a form of carbon) which conducts electricity. Density: Non-metals generally have lower density compared to metals. Melting and Boiling Points: Non-metals typically have lower melting and boiling points compared to metals. Reactivity: Non-metals tend to gain electrons and form negative ions. Their reactivity can also vary (e.g., halogens are highly reactive). Summary: Metals: Shiny, malleable, ductile, good conductors, high density, high melting and boiling points. Non-Metals: Dull, brittle (in solid form), poor conductors, lower density, lower melting and boiling points. 3) Copper Electrical Wiring: Copper is highly conductive, making it an ideal material for electrical wiring in homes, electronics, and power distribution systems. Plumbing: Due to its corrosion resistance and malleability, copper is commonly used in plumbing pipes and fittings. Alloys: Copper is used to make various alloys, such as bronze (copper and tin) and brass (copper and zinc), which are used in everything from musical instruments to machinery. Gold Jewelry: Gold's beauty, luster, and resistance to tarnish make it a popular choice for making high-quality jewelry. Electronics: Gold is used in electronics for its excellent conductivity and resistance to corrosion, often found in connectors, switches, and other critical components. Currency and Investment: Gold has historically been used as money and is still a key asset in investment portfolios, held as bullion or coins. Iron Construction: Iron, particularly in the form of steel, is used extensively in construction for structural supports, reinforcements, and frameworks in buildings and bridges. Automobiles: Iron is a primary component in the manufacturing of automobile parts, including engines and chassis. Tools and Machinery: Various tools and machinery, from hand tools to large industrial machines, are made from iron due to its strength and durability. 4)ans;Chemical Pollution refers to the contamination of the environment by harmful chemicals that are released into air, water, or soil. This pollution can result from various human activities, including industrial processes, agricultural practices, and waste disposal. These chemicals can have detrimental effects on ecosystems, wildlife, and human health. Chemical Pollutant is a substance that causes chemical pollution. It can be any compound that, when released into the environment in significant amounts, negatively impacts ecological balance, public health, or both. Examples: Pesticides (e.g., DDT): Chemical Pollution: The use of pesticides in agriculture can lead to the runoff of these chemicals into nearby water bodies, contaminating rivers, lakes, and streams. Chemical Pollutant: DDT (dichlorodiphenyltrichloroethane) is a persistent organic pollutant that was widely used in the past. It can accumulate in the fatty tissues of organisms and cause harmful effects, including thinning of bird eggshells and health risks to humans. Heavy Metals (e.g., Mercury): Chemical Pollution: Industrial processes such as mining and coal burning can release heavy metals into the environment. These metals can contaminate air, soil, and water. Chemical Pollutant: Mercury is a toxic heavy metal that can accumulate in the food chain, leading to serious health issues like neurological damage and developmental problems, particularly in fish-eating wildlife and humans. Both examples illustrate how chemical pollutants can lead to widespread and severe environmental and health issues.