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Science CBA#2 Review
Question | Answer |
---|---|
pulley | a simple machine, consisting of wheels, that reduces force and helps make work easier |
compound | matter made of two or more elements, such as H2O. |
element | matter that is a pure substance and made of only one kind of atom, such as Carbon (C). |
physical change (also called physical reaction) | occurs when one or more physical properties of a substance are changed, but the substance keeps its identity, such as water changing from a liquid to solid ice. |
chemical change( also called chemical reaction) | occurs when one or more substances are changed into new substances with different properties that can't be change back to the original properties, such as frying an egg |
fossil fuels | fuels such as coal, oil, and natural gas; formed over millions of years from the remains of ancient plants and animals |
renewable resources | natural resources that can be renewed or replaces by nature, such as food crops and solar energy |
nonrenewable resources | natural resources that cannot be replaced once used, such as oil, coal, natural gas, and minerals |
solar energy | energy from the sun in the form of heat and light |
geothermal energy | energy obtained from thermal energy inside the Earth |
biomass | matter formed by plants or animals that is used as a fuel, such as wood or corn oil |
hydroelectric energy | electricity generated using the power of falling water to turn turbines, usually associated with dams |
law of conservation of energy | energy cannot be created or destroyed, it can only change form or be transferred |
potential energy | stored energy an object has because of its position or shape |
kinetic energy | energy an object has because it is moving |
wind energy | electricity produced by using windmills |
A hot nail is placed in a beaker of cold water and allowed to sit for several hours. What will happen to the temperature of both matter? | They will both be the same temperature after a few hours |
radiation | the transfer of energy in the form of electromagnetic waves |
conduction | the transfer of heat from a warmer substance to a cooler substance through direct contact (touching each other) |
convection | the transfer of thermal energy in a fluid (liquid or gas), in which warmer fluid rises and cooler fluid sinks |
speed | distance traveled by an object in a given amount of time, figured by distance divided by time (s = d/t) |
A train travels 1,600 miles in 40 hours. What is its average speed? | 40 mi/h |
A car travels 120 miles in 2 hours. What is its average speed? | 60 mi/h |
A flashlight changes ___________ energy into ____________ energy. | electrical energy into light energy |
You eat lunch and then ride your bike. You are turning ___________ energy into ___________energy | chemical energy into mechanical |
A television converts electrical energy into light and sound energy. The electricity that is not used for light and sound is.... | turned into heat |
Average speed of 400 meters in 45 seconds | 16 m/s |
Average speed of 425 meters in 50 seconds | 8.5 m/s |
Average speed of 375 meters in 55 seconds | 6.8 m/s |
Average speed of 390 meters in 55 seconds | 7.09 m/s |