Exam notes general science

What are three types of measuring scales

the equal arm, the lever arm and the triple beam balance

What is energy measured in and who made the idea

joules and it was created by James Prescott Joule

Explain solids

the particles in a solid substance remain in place and move very little, they vibrate fixed position, this is why solids have a fixed shape and volume, particles form regular pattern

What are the different forms of energy

-heat/ thermal -light/ radiant -mechanical -electrical -chemical -nuclear

What are two methods for measuring the volume of objects

-measuring volume by applying a scientific formula -calculating volume by means of the technique of water displacement

Energy

...

Matter

...

What are the four types of particles

1. atoms: smallest particles from which matter is made only observed help of a microscope 2. molecules: are a number of atoms combined, like bricks arranged together to make a wall 3. elements: are a substance consists one kind of atom ONLY element cannot divide obtain something else 4. compounds: consists of two or more kinds of atoms, can divide provide other substances, some substances could be elements, water common compound, consists elements hydrogen and oxygen

How do you use the water displacement method

1. the measuring cylinder is filled with water to the halfway mark, this mark is your first reading, lower the object carefully into the cylinder from which the volume is determined 2. tap the side of the measuring cylinder to ensure that all air bubbles escape 3. take a reading of the new water level and deduct the first reading with this reading and that is the volume of the object

What is an instrument that can help you with measuring volume

a measuring cylinder

What happens when your eye is not in line with the measuring scale

an error of parallax occurs

What are the types of potential energy

chemical, stored mechanical, nuclear and gravitational

Conductors

conductors allow for the flow of heat in both directions, good conductors are glass, metals, ceramic and water

What are the types of kinetic energy

electrical, radiant, thermal, motion and sound

What is an example of telling the difference between a compound and an element

elements and compounds represented difference loaf of bread and its ingredients

Explain fossil fuels (coal, oil and natural gas)

energy from sun used by plants to make photosynthesis, stored as chemical energy. Plants eaten by animals. Dead plants and animals rot, over millions of years, compressed to make fossil fuels

Explain biomass in the form of dung

energy from sun used by plants, photosynthesis, plants are eaten by animals and people, dung is produced, dung burned to release heat and light energy

Explain biomass in the form of wood (biomass is the total quantity or weight of organisms in a given area and volume)

energy from sun used by trees and plants, photosynthesis, stored as chemical energy, wood from trees can be burned to release heat and light energy

Explain wave energy

energy from the sun heats atmosphere, causing winds and therefore waves, waves drive turbines, generates electricity

Explain wind power

energy from the sun heats the atmosphere, causing winds, wind turns turbines, generates electricity

Explain solar power

energy from the sun is collected and stored in photovoltaic cells to be used as electricity, alternately, flat-plate solar thermal collectors can be used to store the sun's heat energy, which can be used directly, or to heat water, to make steam to drive a turbine to generate electricity

What is the definition of energy

energy is the ability to do work

Heat travels from a warmer material to a colder one

heat is like a tourist-it loves to travel, remember that heat only moves from hot things to colder things, never the other way around, some things let heat travel through them easily and others don't, think of a pot-the heat goes through the pan to the food, but not through the handle to your fingers, remember, the same material that keeps heat tout of something can also keep heat in

What and where do you find energy

in everything and everywhere

Insulators

insulators prevent the flow of heat in either direction, common heat insulators are: fur, feathers, fibreglass, cellulose, stone, wood, brick, dry air, dry cotton or pulp (newspapers), rubber and wool, are poor conductors of heat

What is radiant energy

it is electromagnetic energy that travels in transverse waves, like visible light, x-rays, gamma rays and radio waves, light is a type of radiant energy, an example is solar energy

What is stored mechanical energy

it is energy stored in objects by the application of a force, some examples are compressed springs and stretched rubber bands

What is chemical energy

it is energy stored in the bonds of atoms and molecules, it is the energy that holds these particles together, biomass, petroleum, natural gas, food, batteries and propane are examples of STORED chemical energy

What is mass and what is it measured in

it is how much you weigh and it is weighed in kilograms

What is kinetic energy

it is motion - of waves, electrons, atoms, molecules, substances and objects

What is potential energy

it is stored energy and the energy of position - gravitational energy

What is gravitational energy

it is the energy of position or place, a rock resting at the top of a hill contains gravitational potential energy, an example of gravitational potential energy is hydropower, such as water in a reservoir behind a dam

What is nuclear energy

it is the energy stored in the nucleus of an atom - the energy that holds the nucleus together, this energy is released when the nuclei are combined or split apart

What is electrical energy

it is the movement of electrical charges, electrons in atoms, if you apply force to them you will get electrical charges and electrical charges moving through a wire is called electricity, an example is lightning

What is sound

it is the movement of energy through substances in longitudinal (compression/rarefaction) waves, sound is produced when a force causes an object or substance to vibrate-the energy is transferred through the substance in a wave

What is convection

it is the movement of gases or liquids from cooler spot to a warmer spot, if a soup pan is made of glass, we could see the movement of convection currents in the pan

What is motion energy

it is the movement of objects or substances from one place to another, objects and substances move when a force is applied according to Newton's Laws of motion, an example is wind

What is matter

it is the scientific term building materials composition of all things, objects on earth made of matter - living and non-living things, simply matter is anything, living or non-living, that has volume and a mass

What is a burette

it is used to measure liquid volume, it is better for measuring volumes of smaller than 50 cm, they are marked from top to bottom and usually more accurate than measuring cylinders, the amount of liquid that is tapped from a burette can simply be read from the burette by checking the level of the meniscus

What is fusion

it is when the sun combines the nuclei of hydrogen atoms in a process, fusion, scientist are working on creating fusion energy on earth, so that someday there might be fusion power plants

What is radiation

it is when the sun's light and heat cannot reach us by conduction or connection because space is almost completely empty, nothing can transfer the energy from the sun to earth, sun's rays travel in straight lines, heat rays, when it is moving like this it is called radiation

What is weight and what is it measured in

it is your gravitational pull to the earth and it is measured in newtons

Some materials do not let heat pass through them

materials that do not let heat pass through them are called thermal insulators like a plastic kettle, cork pot stand, wooden handle, oven glove and thermal vest, plastic, cork, wood and fabrics are good thermal insulators, thermal insulators are good for keeping heat out as well as in, cooler box-used to keep food cool, thermos flask and polystyrene cup-used to keep hot drinks hot and cold drinks cold, a good insulator = a poor conductor

What is an excellent conductor of heat and what are not so great ones and what are they called

metals are an excellent conductor of heat energy, not so great ones are wood and plastics these bad ones are called insulators, that is why a pan is usually made of metal while the handle is made of wood or strong plastic

What is fission

nuclear power plants do this by splitting the nuclei of uranium atoms in a process, fission

What is thermal energy

or heat, is the internal energy in substances-the vibration and movement of the atoms and molecules within substances, an example is geothermal energy

Explain liquids

particles able to move freely, cannot go far from one another, do not have fixed pattern can take form of container in which they are, volume cannot really change

Explain gases

particles of a gas more or less move to any place, these particles are also much further apart than the particles in a liquid or a solid substance

What does photovoltaic mean

relating to the production of the electric current at the junction of two substances exposed to light

What are the three basic forms of matter

solid substances, liquids and gases

What are the two forms of energy

stored (potential) energy and working (kinetic) energy

Some materials let heat pass through ten easily

these materials are called thermal conductors, metals are good thermal conductors, because heat passes through them quickly, metals normally feel cold

Heat energy moves in how many many ways and what are they

three ways: conduction, convection and radiation

What is volume

volume refers to the contents of particular spaces

What is conduction

when energy is passed directly form one item to another

What is transformation of energy

when energy un one form is lost, appears in another form, energy stored in petrol is covered into heat in a car engine, heat energy move mechanical parts of the car so the car can move, chemical energy is covreted into kinetic energy, thermal power station the coal is burned heat water into steam, steam turns turbines, turn produces electricity, chemical energy in the coal converted into electrical energy, energy from food finds its origin in solar energy, energy transformed another sort energy, cannot be created and cannot be destroyed, energy has always existed in one form or another

How does it work

when sunlight hits the earth radiation is absorbed or reflected, darker surfaces absorb more of the radiation, lighter surfaces reflect the radiation, you are cooler when you wear light or white clothes in the summer

Is the wind often the result of convection currents

yes, warm air is lighter than cold air so it rises, During daytime land is warm and sea is cool so there is a cool wind coming off the sea, but during night time the directions change - the surface of water is sometimes warmer than the land which is cooler

What two basic rules for getting the correct reading from a measuring cylinder

your eye should be in line with the lower level of the surface of the water (meniscus), the cylinder should be placed on a level surface