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Interesting example of Aliasing

Video vocabulary

start

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US / stɑ:t /

UK / stɑrt /

A1
  • noun
  • First time or place that a thing exists; beginning
  • First opportunity to achieve something, e.g. a job
  • Sudden action or movement because you are scared
  • other
  • Beginning of something in place or time
  • verb
  • To do, be or happen for the first time; begin
  • To turn something on

frequency

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US / 'fri:kwənsɪ /

UK / ˈfrikwənsi /

B1
  • noun
  • Number of repetitions of (radio or sound) wave
  • How often something happens

for

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US / fə(r) /

UK / fɔr,fə /

A1
  • preposition
  • Used to show the purpose, or need of something

time

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US / taɪm /

UK / taɪm /

A1
  • noun
  • Speed at which music is played; tempo
  • Point as shown on a clock, e.g. 3 p.m
  • Number of hours, minutes needed to do something
  • Occasion when something happens
  • Period or occasion that something occurred
  • Period in history or the past
  • Something measured in minutes, hours, days, etc.
  • How long an event takes; duration
  • verb
  • To check speed at which music is performed
  • To choose a specific moment to do something
  • To measure how long an event takes, e.g. a race
  • To schedule something to occur at a specific moment

much

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US / mʌtʃ /

UK / mʌtʃ /

A1
  • adjecitve
  • Very; to a high level or degree
  • adverb
  • A lot; large amount; a high degree of
  • Nearly; basically
  • On many occasions; often
  • noun
  • A large amount; a great quantity

low

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US / ləʊ /

UK / lo /

A1
  • adjecitve
  • Having a small quantity, supply, or amount
  • Being unhappy or unpleasant in attitude
  • Not high; being near the ground, or bottom
  • (Of a voice, sound) being soft; quiet
  • noun
  • Situation of not having a lot of something

rotational

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US / rəʊ'teɪʃənl /

UK / roʊ'teɪʃənl /

B2
  • adjecitve
  • Concerning rotation

moment

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US / 'məʊmənt /

UK / 'moʊmənt /

A1
  • noun
  • Very short or brief period of time
  • A particular period in time

without

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US / wɪˈðaʊt /

UK / wɪðˈaʊt, wɪθ- /

A1
  • preposition
  • Not with; not having

his

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US / hɪz /

UK / hɪz /

A1
  • pronoun
  • Something belonging to a male person

see

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US / si: /

UK / si /

A1
  • verb
  • To go on a date with someone
  • To predict whether something is, or will be true
  • To understand what someone says
  • To use your eyes to look at something
  • To visit a place often for sightseeing or pleasure
  • To visit or meet with someone
  • To find out by waiting or looking
  • To watch (a game, movie or TV show)

have

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US / həv /

UK / hæv /

A1
  • verb
  • To drink, smoke, eat or use something
  • To experience the effects of something
  • To organize an event, or join in an activity
  • To own, possess, or hold something
  • To cause to happen or produce a particular effect

actuality

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US / ˌæktʃuˈæləti /

UK / ˌæktʃuˈælɪti /

B2
  • noun
  • The state of existing and being real

sample

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US / ˈsɑ:mpl /

UK / ˈsæmpl /

A2
  • noun
  • A small quantity of something used as a taster
  • verb
  • To try (e.g. food, drink), to see if you like it

yep

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US / jep /

UK / jɛp /

B2
  • noun
  • Another way of saying 'yes'

they

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US / ðeɪ /

UK / ðe /

A1
  • pronoun
  • Two or more people, animals, or things

string

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US / strɪŋ /

UK / strɪŋ /

A2
  • noun
  • A line of connected objects
  • Thick thread; thin rope
  • verb
  • To tie or connect things together with a thread

apparent

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US / ə'pærənt /

UK / əˈpærənt, əˈpɛr- /

A2
  • adjecitve
  • Easy to see or clearly understand
  • Seeming to exist or be true, but may not be

look

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US / lʊk /

UK / lʊk /

A1
  • noun
  • Person's beauty or physical attractiveness
  • Particular style of dress, clothes, or appearance
  • The way someone, something appears to be
  • Act of searching for or examining something
  • verb
  • To appear to be; seem

device

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US / dɪˈvaɪs /

UK / dɪˈvaɪs /

A2
  • noun
  • Object, machine, or equipment for a specific use
  • Method of doing something; a way

fast

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US / fɑ:st /

UK / fæst /

A1
  • adjecitve
  • In a way that is difficult to move or change
  • Moving or able to move quickly
  • Showing time that is later than the actual time
  • adverb
  • With a great deal of speed
  • noun
  • Period of time when a person chooses not to eat
  • verb
  • To refuse food for a long time

show

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US / ʃəʊ /

UK / ʃo /

A1
  • noun
  • False display of love, emotion or action
  • An event for displaying or promoting goods
  • Play, opera or theater production
  • Presentation that is broadcast on TV or radio
  • verb
  • To be easily seen or displayed
  • To display your emotions or feelings
  • To let someone see something; display
  • To explain or teach how something is done
  • To lead someone somewhere; point them to something
  • To prove something to be true, correct
  • To reveal or allow something to be seen

take

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US / teɪk /

UK / tek /

A1
  • noun
  • Filming of a single scene for TV or the movies
  • verb
  • To accept something that is offered
  • To use a method of traveling, e.g. a bus or train
  • To use a camera to make (a photo)
  • To pick up something and go away with it
  • To study a subject in school
  • To attempt to pass (an exam)
  • To require a certain amount of time, money, space

hertz

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US / hɜ:ts /

UK / hɜ:rts /

B2
  • noun
  • Unit for measuring the frequency of sound waves

very

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US / 'verɪ /

UK / ˈvɛri /

A1
  • adjecitve
  • Concerning a large degree or amount
  • adverb
  • A lot; much; many
  • Used to stress or emphasize a noun

principle

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US / ˈprɪnsəpl /

UK / ˈprɪnsəpəl /

A2
  • noun
  • Moral rule or belief governing a person's behavior
  • Natural law that explains how things work

several

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US / ˈsevrəl /

UK / ˈsɛvərəl,ˈsɛvrəl /

A1
  • adjecitve
  • Many of
  • pronoun
  • More than two but not a large amount

get

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US / ɡet /

UK / ɡɛt /

A1
  • verb
  • To become affected by illness or disease
  • To begin to feel or understand an emotion or idea
  • To send or bring someone or something home, etc.
  • To go somewhere to obtain something
  • To (cause to) do a particular thing
  • To obtain, receive or be given something
  • To currently have
  • To prepare for use
  • To understand something being said or read

what

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US / wɒt /

UK / hwɑt, hwʌt, wɔt, wʌt,hwət, wət /

A1
  • pronoun
  • Thing or things that; the same kind as
  • Used to emphasize something you are about to say
  • adjecitve
  • Used to refer to a particular amount, or number
  • Used to place emphasis on a particular quality
  • adverb
  • To a certain degree
  • determiner
  • Question words used for asking for information
  • exclamation
  • Used to express excitement, shock, or surprise
  • Used to ask people to repeat something they said

fun

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US / fʌn /

UK / fʌn /

A1
  • adjecitve
  • Amusing and enjoyable
  • noun
  • Enjoyable or amusing quality or feeling

enough

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US / ɪˈnʌf /

UK / ɪˈnʌf /

A1
  • adjecitve
  • Sufficient to answer the need
  • adverb
  • To a satisfactory degree
  • pronoun
  • Equal to what is needed; as much as required
  • Adequate number or amount

like

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US / laɪk /

UK / laɪk /

A1
  • adjecitve
  • Being equal in status or kind to something else
  • Similar; the same
  • adverb
  • For example
  • preposition
  • Used as a filler; used to ad emphasis
  • In a way similar to the way something is done
  • Such as; for example
  • verb
  • To want to
  • To find something pleasing; to prefer something

catch

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US / kætʃ /

UK / kætʃ, kɛtʃ /

A1
  • noun
  • Amount of something that has been caught
  • Trick or something trying to deceive
  • verb
  • To stop something flying and hold it
  • To stop something and not let it go, e.g. animals
  • To get sick or get a disease from someone else
  • To find someone to do something, a task
  • To get stuck on or in something
  • To be trapped so you can’t escape
  • To be able to understand what someone is saying

about

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US / ə'baʊt /

UK / əˈbaʊt /

A1
  • adverb
  • To be ready to; going to
  • Nearly; approximately; roughly
  • Near; next to; close to
  • In every direction; in the area of
  • preposition
  • Concerning or of (a topic)

that

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US / ðæt /

UK / ðæt, ðət /

A1
  • adjecitve
  • The person or thing being talked about
  • Used to identify something both the speakers know
  • adverb
  • Used to reinforce adjectives and adverbs
  • To such a degree
  • conjunction
  • Used to connect a noun clause
  • Used to introduce an adverbial clause
  • Used to introduce a noun clause
  • determiner
  • Used as a noun to refer to something
  • pronoun
  • Referring an object far away
  • Used to refer to the relative pronoun ‘which’

find

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US / faɪnd /

UK / faɪnd /

A1
  • noun
  • Object discovered by chance
  • Things that have been discovered from searching
  • verb
  • To become aware of something that is happening
  • To discover or meet by chance
  • To decide if someone is guilty of a crime, or not
  • To learn through study, research, or effort
  • To discover something by looking for it

happen

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US / 'hæpən /

UK / ˈhæpən /

A1
  • verb
  • To take place or occur

rotation

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US / rəʊˈteɪʃn /

UK / roʊˈteɪʃn /

B2
  • noun
  • Regular change of the crops grown in a field
  • Group who take turns performing a certain task
  • Regularly changing the time when people work
  • Movement in a circle around a central point

value

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US / 'vælju: /

UK / ˈvælju /

A1
  • noun
  • Importance you attach to something
  • Some information expressed as a number
  • Stated price of something; worth
  • verb
  • To place a high importance on something
  • To say how much money something is worth

case

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US / keɪs /

UK / kes /

A1
  • noun
  • Container used to carry things, e.g. clothes
  • Set of facts about a crime
  • Set of facts about an event
  • Example or instance of something
  • verb
  • To find out about a place, as in planning to steal

our

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US / 'aʊə(r) /

UK / aʊr /

A1
  • determiner
  • Belonging to us

can

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US / kæn /

UK / kən,kæn /

A1
  • noun
  • A metal container for storing food
  • other
  • Able to; have the skill to; have the time to
  • verb
  • To have permission to
  • To be possible to do
  • To preserve food by sealing it in a metal container

now

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US / naʊ /

UK / naʊ /

A1
  • adverb
  • At the present time or moment
  • Right away or in the next possible moment
  • Used to refer to something that just happened
  • Time between the present and a moment in the past
  • conjunction
  • Resulting from or because of something

stroboscope

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US / ˈstrəʊbəˌskəʊp /

UK / ˈstroʊbəˌskoʊp; ˈstrɑːbəskoʊp /

C2
  • noun
  • Flashing light making moving objects appear still

not

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US / nɒt /

UK / nɑt /

A1
  • adverb
  • Word indicating the negative
  • (Used to form the negative of verbs)

want

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US / wɔnt /

UK / wɑnt, wɔnt /

A1
  • noun
  • Something you desire or wish for
  • State or condition of poverty
  • verb
  • To desire or wish for something; hope for a thing

measure

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US / ˈmeʒə(r) /

UK / ˈmɛʒɚ /

A1
  • noun
  • Plan to achieve a desired result
  • Tool used to calculate the size of something
  • verb
  • To determine the value or importance of something
  • To calculate size, weight or temperature of

but

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US / bət /

UK / bʌt,bət /

A1
  • conjunction
  • Used before you say something different, opposite

become

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US / bɪ'kʌm /

UK / bɪˈkʌm /

A1
  • verb
  • To begin to be; grow to be; develop into
  • To be suitable for a particular job or role

study

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US / 'stʌdɪ /

UK / ˈstʌdi /

A1
  • noun
  • Room that a person studies or reads in
  • Piece of research
  • Topic or subject you research or learn about
  • verb
  • To focus on learning something usually at school

maybe

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US / ˈmeɪbi /

UK / ˈmebi /

A1
  • adverb
  • Possibly but not certainly; perhaps

slime

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US / slaɪm /

UK / slaɪm /

B2
  • noun
  • Thick slippery substance, often rather disgusting

this

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US / ðɪs /

UK / ðɪs /

A1
  • adjecitve
  • Used to indicate something already been discussed
  • Used to indicate something happening around now
  • adverb
  • An indication by a physical motion or gesture
  • A specific amount of
  • determiner
  • Person, thing, or idea near you
  • pronoun
  • Person, thing that has already been discussed

half

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US / hɑ:f /

UK / hæf, hɑf /

A1
  • adjecitve
  • Not complete
  • adverb
  • Partly; somewhat
  • noun
  • One of two equal periods of game time in a sport
  • The part you get when one is divided into two;

you

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US / jʊ /

UK / ju /

A1
  • pronoun
  • Person someone is speaking or writing to
  • Person or people in general

turn

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US / tɜ:n /

UK / tɚn /

A1
  • noun
  • Place where changing of direction happens
  • Your time or chance to perform a duty
  • Your chance to play or do in say a game
  • Unexpected change, as in the weather
  • verb
  • To become (a particular age)
  • To become a different quality, color, etc.
  • To change the direction of something, e.g. a car
  • To move in an opposite direction or position
  • To shape metal with a spinning tool

one

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US / wʌn /

UK / wʌn /

A1
  • pronoun
  • You; we; people in general; someone
  • The thing or person previously referred to
  • adjecitve
  • Used to refer to people generally
  • Being a strong example of (something mentioned)
  • number
  • Number 1

rate

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US / reɪt /

UK / ret /

A1
  • noun
  • Current price or cost of something
  • Speed or frequency of events over time
  • verb
  • To assess something or consider its qualities

than

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US / ðən /

UK / ðən /

A1
  • conjunction
  • Used to compare two things that are not equal

invent

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US / ɪnˈvent /

UK / ɪnˈvɛnt /

A2
  • verb
  • To create something such as a story or excuse
  • To create something useful for the first time

the

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US / ðə /

UK / ðə /

A1
  • article
  • Used to refer to something already mentioned
  • Used to show there is only one of something
  • determiner
  • Used to describe all of a family

make

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US / meɪk /

UK / mek /

A1
  • noun
  • Product made by a particular company; brand
  • verb
  • To arrange or prepare something e.g. dinner
  • To get to (a place) on time
  • To gain the status of (teacher, lawyer, etc.)
  • To create something by putting things together
  • To earn a certain amount of money at a job
  • To cause or force a person to do something
  • To cause something to happen or be formed

alright

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US / ɔ:lˈraɪt /

UK / ɔlˈraɪt /

A2
  • adjecitve
  • OK; fine; good

another

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US / əˈnʌðə(r) /

UK / əˈnʌðɚ /

A1
  • adjecitve
  • One more, but not this
  • determiner
  • One more added
  • pronoun
  • One more (thing)

something

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US / ˈsʌmθɪŋ /

UK / ˈsʌmθɪŋ /

A1
  • adverb
  • In some degree or measure
  • noun
  • a person or thing of some value or consequence
  • pronoun
  • Thing that is not yet known or named
  • Approximately

until

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US / ənˈtɪl /

UK / ʌnˈtɪl /

A1
  • conjunction
  • Up to; to a time when something happens
  • preposition
  • Before (a specific time)

kid

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US / kɪd /

UK / kɪd /

A2
  • adjecitve
  • Made from young goat skin
  • noun
  • Child or young person
  • Young goat
  • verb
  • To make fun of someone in a gentle way; to tease

and

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US / ənd /

UK / ənd, ən,ænd /

A1
  • conjunction
  • Used to refer to two or more things
  • Plus; in addition; on top of that
  • Used to introduce an action that follows another

false

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US / fɔ:ls /

UK / fɔ:ls /

A2
  • adjecitve
  • Not real or genuine

call

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US / kɔ:l /

UK / kɔl /

A1
  • noun
  • A order or request for action
  • The sound an animal makes, often when in danger
  • A correct prediction, e.g. a decision in a game
  • A short visit to a place or person
  • A decision by a referee or umpire in a game
  • verb
  • To make a request or order for action
  • (Animal) to make sounds to warn of danger
  • To announce the date of an election
  • To make a judgment about something
  • To give someone or something a name
  • To guess in advance the result or outcome
  • To visit a place or person for a short time
  • To phone someone
  • To speak, announce or shout in a loud voice

inertia

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US / ɪˈnɜ:ʃə /

UK / ɪˈnɚʃə /

C1
  • noun
  • Lack of movement or activity

true

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US / tru: /

UK / tru: /

A1
  • adjecitve
  • Agreeing with the facts; not false; real or actual

here

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US / hɪə(r) /

UK / hɪr /

A1
  • adverb
  • In this place; at this location, position or time

wheel

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US / wi:l /

UK / wi:l /

A2
  • noun
  • Round thing that rolls, used for moving things
  • verb
  • To move something which has wheels or is on wheels
  • To turn or cause to turn something in a circle

appear

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US / ə'pɪə(r) /

UK / əˈpɪr /

A1
  • verb
  • To be seen, become visible; come into sight
  • To seem to be
  • To act in a play, movie, or be mentioned in media

will

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US / wɪl /

UK / wɪl /

A1
  • noun
  • Desire or choice of someone
  • Document saying who gets your money when you die
  • Strong desire to do something; determination
  • Desire to do something; strong wish to do
  • other
  • Used with verbs to express the future
  • verb
  • To leave property to someone after your death
  • To use mental effort to make something happen
  • Am (is, are) likely to do
  • To influence someone to do something
  • To make something happen by strongly wanting it

once

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US / wʌns /

UK / wʌns /

A1
  • adverb
  • One time; one instance
  • At a time in the past
  • conjunction
  • When; as soon as

actually

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US / ˈæktʃuəli /

UK / ˈæktʃuəli /

A1
  • adverb
  • Used to add new (often different) information

science

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US / 'saɪəns /

UK / ˈsaɪəns /

A2
  • noun
  • Study of the physical world, based on facts
  • Subtitles section
  • Okay, I snuck a moment without the kids to do this for you.
  • I'm gonna show you a principle called aliasing.
  • Aliasing is when your sample rate of your measuring device is not fast enough to actually catch the true frequency of what's happening.
  • So you can get a false reading.
  • So here there's a string and we can turn this string on so that it rotates.
  • Got a rotating wheel here.
  • And here we have a stroboscope invented by Dr. Edgerton.
  • So we will turn the stroboscope until you can actually stop the rotation of this string.
  • So here It looks like the string is rotating at about one hertz or maybe more like half a hertz.
  • But in actuality it's rotating much, much faster than that.
  • Something like 40 or 50. So the sample rate of the stroboscope or the time at which you're taking a measurement is not fast enough to get the true value.
  • There you go.
  • So here the sample rate appears to be very, very or the measured value seems to be very, very low.
  • Yep, that's it.
  • So once we turn up our measurement frequency you can see that it starts to become more apparent that it's rotating.
  • And you can actually get another false measurement here.
  • Looks like there's several strings, which is not the case.
  • Alright, that's it.
  • Daddy's had his science fun.
  • Now I gotta go find the kids.
  • Okay, they're studying rotational inertia.
  • Slime.
  • You wanna make some slime?
  • I want to go and get some slime.
  • Slime!