[Music] n [Music] and you know you were saying and that's why she was try sorry I'm late I was shopping for my niece she turns 12 tomorrow unprofessional don't ever ask me for a tardy pass my little sister's about to turn 12 too what did you get her cuz they are so hard to buy for I got her this um I won't judge but what 12-year-old can fit into that and it's ugly I I didn't say she was 12 12 years old um yes you did no I said she turns 12 tomorrow you must have just turned 90 yesterday cuz your memory is off I thought he was only 40 but he is B she'll be 12 months old tomorrow oh you're being extra no one says that just say she'll be one well the real issue here is that units matter so much of our physical world is governed by quantities and without units for those quantities we will be confused anytime anyone mentions a number age is simply a measurement of time and time has several different units correct now granted when we speak about age it tends to be in years but it doesn't have to be example today is August 12th right if I told you my niece was born on August 1 of this year how old is she today 12 days old right if she was born at 11:00 p.m. last night how old is she um oh she'd be 12 hours old if I told you she was born as I was getting off the highway to come to work how old is she oh 12 minutes old right so just saying 12 means nothing without a unit attached to it in science units are very important because we spend a lot of time measuring and recording data if I needed to measure the amount of time left in class and told you it was 30 You' be really happy to know that it's just 30 minutes that's not something to be happy about well would you prefer 30 hours seconds nice 30 seconds but our units have to be aligned and uniform to avoid confusion we'll be doing a lot of experiments in this class where we will be discussing and measuring length how long is this table I'd say about four feet no it's not that short it has to be like 120 cim way too long like look at table you see you both are correct how well this table is 120 cm long and that just happens to be about 4T long I knew I was right however was also I'm going to side with a Benny this time only because centimeters is a metric unit Matt you use feet inches feet miles gallons quarts pints ounces pounds those are all us customary units and while you may use them all of the time in the United States in your daily life I want you to be prepared to measure read and work with data all over the world you'll find that most of the world uses metric units meters liters and GS to measure length volume and mass metric units work by taking the base unit like meters lers and GS and you can just tack a prefix in front of them to make them larger by powers of 10 so there are 10 m in one decameter 100 m in one hectometer and 1,000 m in one kilometer kilometers hectometers and decameters are all larger than 1 meter then you have Dei CTI and millimeters they are all smaller than a meter so it works backwards for those prefixes there are 10 decim in 1 M there are 100 cm in 1 M and you can fit 1,000 mm in 1 m but question which value is larger 10 decim or 100 cm um it's clearly 100 actually they're the same value think about this do 100 pennies have a greater value than 10 dimes no no exactly they both have the same value just like 100 pennies is the same as $1 another benefit of using metric units is that it's very easy to convert between them Matthew how many miles are in 4T I got time for that well there are 5,280 ft in one mile so how many miles are in 4 ft let me get my calculator without a calculator can I get a pass to the counselor I'm trying to withdraw while he's doing can a Benny how many kilometers are in 120 CM uh 012 kilm how' you get that so fast well based on what you said earlier if this is 12 120 CM then there are 12 decim in that 1.2 m in that2 decam in that and 012 hectometers and 012 kilom in that measurement so just say you move the decimal um don't you have a math problem to do I'm almost done how many millimeters are in 120 CM same way so Millie is 10 times smaller than centimeters so there will be 1,200 mm in 120 CM excellent which one is longer 120 CM or 1,200 mm um they're the same you just told us that right do you want to count them I am not doing that converting between metric units is extremely simple as you need to move between the prefixes just simply move the decimal okay I'm done there are 00758 miles in 4T uh how did you get that divided four by 5,280 but with no calculator that took me back and I haven't done long division in so long and then the number started repeating you you used the calculator didn't you um yeah I care about my mental health I actually appreciate that me too converting between us custom a units is actually more complex it requires memorization of or research of conversion factors which tend to be strange and arbitrary numbers this can be done and we actually do have a lesson coming up on that but if you had to pick which one would you rather use metric or us custom a units for conversion metric certainly met metric system for sure all right well Matt you missed our explanation so let's go over converting between metric units again first step I like to put all of the prefixes in line kilo hecto Deca the base unit desie cinti and Millie uh I don't think I remember that there too much oh oh I have something my old teacher taught me once to help remember I got one yes I know what she said um Kanye hates dressing babies during campaign meetings um that is not what she said I was going to say King Henry died by drinking chocolate milk actually I like that first one thank you yeah anyway they're both stupid but it's just a neonic device to help you remember the order M so let's work on it I'm 1.75 m tall how tall am I in millimeters so we look at our line of prefixes where are we starting on this line um I don't see meters on this line anywhere well that's because we're starting at the base unit meters is the base unit just like liters and GRS how far away from the base unit is Millie Millie is one two three spaces to the right awesome so let's move our decimal three spaces to the right and then we'll f fill in these empty spaces with zeros so ah so you're 1,750 mm tall 1,750 mm tall correct let's work on another one your grandma's pound cake recipe requires 2 Cen of milk how many decaliters would that be no one's Grandma measures milk in decaliters all right my grandma uses cups so where are we starting we're starting in centiliters are we moving to desie or are we moving to Deca ah Deca I almost got confused they look similar right so let's move our decimal I don't see it h if you don't see the decimal remember that it's always at the end of a whole number ah 2 dealers of milk very good how how much do you weigh uh don't ask me that okay how much do I weigh how much do you think that I weigh I don't know you look dangerously thin right who animated us anyway I say you're at least 90 lbs and you're an adult man well remember we don't use pounds in this class that's a US custom a unit I'll let you know I'm actually 70 kilg what is my mass in milligrams oh go all the way over there well where are we starting up here we're starting at kilo right and we're moving to Millie how many spaces are we moving uh that's six spaces to the right six yes and let's fill in the empty spaces with zeros 70 million milligrams you're fatter than I thought am I really because one of the main points that I'm trying to drive home is that while we converted between these they are still the same value 90 kg if I was 90 kg that would be greater than 70 million mg but 70 kg is equal to 70 million milligram either way you need to get your weight up that's unhealthy I'm calling your doctor we don't do body shaming here [Music]