in this video we're going to talk about the SI base units and also some derived units now the SI base unit for length is the meter you can convert the meters into kilometers feet inches centimeters miles there's many different units of left but according to the International System of Units for length it's the standard unit is the meter from Mass it's the kilogram standard unit for time is the second or temperature it's Kelvin for quantity it's the mole for electrical current it's the amps and for luminous intensity it's Candela or CD now let's talk about lead first here are some common conversion factors that you want to be familiar with one kilometer is equal to a thousand meters one meter is equivalent to a hundred centimeters one mile is equal to 1.609 kilometers and one mile is also equal to 5280 feet now this three feet in one yard and there's 12 inches in a foot and one inch is equal to 2.54 centimeters so when dealing with left those are some common conversion factors that you want to be familiar with when dealing with Mass the most common conversion factor you'll typically need is this one one kilogram is a thousand grams in chemistry a lot of times you'll be dealing with your grams when it comes to mass but in physics you'll typically deal with kilograms in regards to Mass now for both chemistry and physics the most common unit of time that you'll be using is the second as you know there are 60 seconds in one minute and there's 60 minutes in an hour there's 24 hours in a day seven days per week an average of 30 days per month and one year is equal to 365 days by the way a light year is not a unit of time rather a light year is a unit of distance now let's move on to temperature if you want to convert from Celsius to Kelvin you could use this formula the Kelvin temperature is the Celsius temperature Plus 273.15 and if you want to get the Fahrenheit temperature from Celsius you could use this equation it's 1.8 times the Celsius temperature Plus 32. now whenever you see the mole the mole represents a quantity which typically used in chemistry think of the word dozen a dozen is equal to a specific number 12. if you have a dozen eggs you have 12 eggs if you have a dozen calculators you have 12 calculators a mole also represents a quantity but it's a large quantity of something specifically 6.02 times 10 to the 23. which is also known as Avogadro's number so if you have a mole of books you have 6 times 10 to 23 books if you have a mole of pillows you have 6 times 20 times 10 to the 23 pillows so a mole is just a very large quantity of something now electric current the unit for electric current is the amp and I'm going to talk more about that a little bit later in this video first let's go over something called a derived unit velocity velocity and speed they have the same unit velocity is displacement over time speed is distance over time displacement has the units meters when the base unit for time is seconds so for velocity the derived unit is going to be meters per second foreign acceleration that's a very common Topic in physics acceleration is the change in velocity divided by the change in time velocity is typically measured in meters per second and times in seconds so when you take meters per second and divide it by seconds you get meters per second squared or the derived unit for acceleration now let's move on to the next physics topic Force what can we say about Force according to Newton's Second Law force is equal to mass times acceleration the standard unit of force is the Newton it's basically a derived unit so Force which is measured in Newtons is equal to the mass which is measured in kilograms times the acceleration which is meters per second squared so one newton is equal to one kilogram times one meter per second squared so that's the equivalent derived unit Force now we've talked about length which is in meters area is square meters so think about if you have the area of a rectangle it's left times width the length of the rectangle can be measured in meters the width can also be measured in meters when you multiply meters by meters you get square meters now area could be also in terms of other units of left it's length squared so you could have square feet square yards you could have square inches square kilometers square miles acreage an Acura is a unit of area Now volume if you think of a volume of a rectangular prism it's length times width times height so when calculating volume you multiplying meters by meters by meters so you get cubic meters in physics you'll typically see volume in terms of cubic meters in chemistry you'll typically see it reported in liters so it's good to know the conversion between the two to make space I'm just going to get rid of this one cubic meter is equivalent to one thousand liters and one liter that's equal to a thousand milliliters and one cubic centimeter is equal to one milliliter so in chemistry you'll see volume typically reported in liters milliliters or even cubic centimeters in physics volume is typically reported in cubic meters so it's good to know that now let's talk about pressure what can we say about pressure in physics is force divided by area so imagine applying a force over an area you're applying pressure to that area now pressure is measured in pascals in physics Force we know is Newtons area is square meters so one pascal is equal to one newton per square meter now in chemistry pressure is typically measured in atmospheric pressure ATM sometimes you'll see it measured in the unit torque or millimeters of mercury so here's the conversion for those of you who want to know One ATM this is pressure of air at sea level one atmospheric pressure that's equal to 101.3 kilopascals so if you want to convert this to a unit in physics that's 101 300 pascals Now One ATM is also equal to 760 units of tor which is also equal to 760 millimeters of mercury Mercury is typically used to measure pressure in certain devices so that's why you'll see it reported as a unit now the next derived unit that we're going to talk about is density now density is equal to Mass divided by volume in chemistry the mass is typically in grams the volume can be in cubic centimeters or milliliters so in chemistry you'll see the density reported as grams per cubic centimeter or grams per milliliter in physics the mass is usually reported in kilograms and the volume is typically reported in cubic meters so in physics you'll see density as kilograms per cubic meters now here's the conversion between the two so because milliliters and cubic centimeters are the same and these two units will have the same value but these two units to differ by a thousand so for instance the density of aluminum in chemistry you'll see it as 2.7 grams per cubic centimeter in physics this is reported as 2700 kilograms per cubic meter now keep in mind our kilogram is a thousand grams but a cubic meter is one million cubic centimeters when you have a million divided by a thousand you get a multiplication factor of a thousand so if you look at these two one cubic meter is a thousand liters and one liter is a thousand milliliters so a cubic meter is a million milliliters which is equivalent to a million cubic centimeters and one kilogram is a thousand grams so we need to divide a million by a thousand you get a thousand so that's why these two differ by a thousand now the next thing we're going to talk about is something called Warp and we'll also talk about energy now work and energy you can measure them both with the same unit and that is the typically reported in the unit of joules now there are other units that represents energy can be represented in calories there's also kilocalories and there's also electron volts these are other units of energy the most common unit of energy data that you'll typically see is the joule that work is equal to force times displacement force is measured in Newton's displacement is measured in meters and what this means is that one joule is equal to one newton times one meter now there's other ways to describe energy as well for instance if you think about this formula kinetic energy it's one half MV squared the masses in kilograms the speed is meters per second but it's squared and that's going to be equal to a joule so we can also say that one joule is equal to one kilogram times a square meter divided by a square centimeter I mean divided by a square second so a joule is equivalent to those units as well now let's talk about the conversion each one these two for those of you who are interested one electron volt is equal to 1.602 times 10 to the negative 19 joules now when dealing with thermal energy particularly Heat you'll see calories in kilocalories biblically represented as a unit of energy so one Capital calorie is equal to a thousand lowercase calories which is equivalent to one kilocalorie and one lowercase calorie is equal to 4.184 tools this is based on the specific heat capacity of water the specific heat capacity of water is 4.184 joules per gram per Celsius that's where the unit calorie comes from it's how much thermal energy can be stored in water per degree celsius per one gram of water so here's what it means let's say if you have one gram of water let me draw a picture so because the density of water is one this is equivalent to a milliliter of water so we have one gram of H2O and let's say the temperature of this sample is 25 degrees Celsius it's going to take us 4.18 or joules of heat energy if we apply this amount of heat energy to one gram of water the temperature of that sample of water will increase by one degree Celsius so it's going to go up from 25 to 26 degrees Celsius that's the basic idea behind this specific heat capacity of water it tells you how much energy water can absorb in order to increase its temperature by one if you have one gram of water so water can store a lot of energy the specific heat capacities of metals is much lower than this number so water can store a lot of thermal energy before increase in its temperature by one degree Celsius foreign it has a very high heat capacity now the next unit we're going to talk about is power or rather the next thing we're going to talk about Now power is a rate before we talk about power work in energy even though they look similar they're not the same energy is basically something that's is possessed by something so for instance and a ball can have energy a ball that's moving has kinetic energy a ball that's on a hill has potential energy so a ball can possess energy however you can a ball can't possess work so work and energy are not the same work is more of a mechanism it's a mechanism by which energy is transferred so if you were to apply a force let's say on this block you can increase the kinetic energy of that block as the block begins to move from rest so that force is doing work on that block it's increasing the Block's kinetic energy because as the block speeds up the kinetic energy will go up so that force is doing work on the block by transferring energy from one object to another so let's say if a ball strikes that block when the ball strikes the block the ball is going to slow down but the block is going to speed up energy is transferred from the ball to the block so the ball is doing work on the Block so work is really a mechanism by which energy can be transferred but they can both be represented with the same units which is joules Now power is the rate at which energy is transferred so power is work divided by time because you could transfer the energy in a slow rate or you could transfer the energy at a very high rate so power tells you how fast that energy is being transferred the unit of power is the what which is equal to joules per second so one watt is one joule per second a horsepower is a typical unit of Watts one horsepower is 746 Watts so if you think about what that means that means that 746 joules of energy is being transferred every second so let's say if you have a car that has an engine that can generate 300 horsepower if you multiply that by 746 that's 200 23 800 watts so this engine or this car with an engine of 300 horsepower can transfer 223 800 joules every second that means in 10 seconds it could transfer 2.2 million joules of energy so I want you to understand that concept power is the rate at which energy is being transferred so one watt is one joule per second and it's good to know this one as well a kilowatt is a thousand Watts now when dealing with electricity there's a unit called kilowatt hours if you look at your electric bill you'll see this now don't get confused between kilowatts and kilowatt hours kilowatt is the unit of power so I'm going to put that here kilowatt hours is a unit of energy remember how we said that power is work over time you can also describe power as being energy over time energy and work there related to each other they have the same units if you solve for energy by multiplying both sides by T you get that energy is power multiplied by time so the power can be in kilowatts hours is a unit of time when you multiply Power by time you get energy therefore the kilowatt hour is a unit of energy and not power so make sure you understand that difference though so if you see kilowatt hours that is a unit of energy if you see kilowatts it's a unit of power now let's talk about momentum momentum is basically mass in motion it's represented by this symbol lowercase p its mass times velocity masses in kilograms velocity is meters per second so momentum is just kilograms times meters per second now there's something called the impulse momentum theorem import let me say that again impulse is force multiplied by time the impulse is equal to the change in momentum mass times the change in velocity so forces and Newtons time is in seconds masses in kilograms V is in meters per second so momentum can be represented as kilograms times meters per second but it can also be represented as Newtons times seconds so that's why I wanted to mention the impulse momentum theorem so you know that those two units are equivalent to each other now let's talk about frequency you're going to encounter this topic when dealing with waves it could be light waves sound waves or even simple pendulum frequency is equal to 1 over the period the period is the time it takes to complete one cycle the frequency is the number of cycles that occur per second the frequency is measured typically in hertz so imagine having a one kilohertz sound wave or a 500 Hertz sound wave Hertz is the unit of frequency and period is measured in seconds so one Hertz is equal to one seconds to the minus one or one over seconds now let's talk about electricity so we said that the SI unit for electric current is the amps the unit 4 electric charge is the column so think of how moles represents the quantity of something electric charge represents the quantity of charge or the total quantity of charged particles but it's more accurate to say the total quantity of charge because some particles can have more charge than others so it really represents the quantity of charge now Q is equal to i t Q is the charge measured in columns I in physics is the electric current measured in amps time is in seconds so if you solve for I you get Q over t so what this means is that one amp of current is equal to one coulomb per second so electric current is the rate at which electric charge is flowing through a circuit much the same way as power is the rate at which energy is being transferred so electric current tells you how much charge is flowing through a wire at any given second or rather per second now electrical resistance resistance is measured in ohms so we have V is equal to IR if you solve for resistance it's a voltage divided by current so one ohm is basically one volt divided by one amp electric potential is measured in volts voltage is electric potential difference if you have two points and you know the electric potential between if you know the electric potential of both those points the difference in that potential is voltage so just to illustrate that concept let's say this is point a and this is point B let's say point a has an electric potential of 300 volts point B has an electric potential of 500 volts now these two values they don't represent voltage they represent electric potential and it's specific to a point in space voltage is the difference between those two points so voltage is electric potential difference the voltage between those two points is 200 volts so when dealing with voltage you need to compare the electrical potential of two points if you just have one point you're talking about electric potential and not voltage however both electric potential and voltage they have the same unit which is the volt now electric potential represented by the symbol V is equal to potential energy divided by the charge so electric potential is the ratio of potential energy to charge so one volt means that you have one joule of electric potential energy per one coulomb of charge a hundred volts can mean multiple things it can mean that you have a hundred joules of electric potential energy per one coulomb of charge or it can mean that you have one joule of electric potential energy per point zero one kilometers five there's many ways in which you could see that so that's electric potential it's the ratio of energy to charge so voltage the unit volt that is a derived unit velocity acceleration force those are derived units but the first seven that we went over those are the SI base units like the meter the kilogram the second the mole Kelvin amps Candelas those are the seven common acid base units so that's basically it for this video hopefully it gave you a good introduction into SI base units and derive units thanks for watching