Experimental Design (ACT-Science Prep)

00:05:40
https://www.youtube.com/watch?v=Q9CyC4Nw4fg

الملخص

TLDRÎn sesiunea aceasta de învățare, sunt explicate conceptele esențiale ale designului experimental, incluzând variabilele independente și dependente, variabilele constante și grupul de control. Exemplul analizat implică un tabel de date cu zinc și acid clorhidric, unde masa de zinc este variabila independentă, schimbarea temperaturii este variabila dependentă, iar volumul acidului și presiunea atmosferică sunt variabile constante. În plus, este oferit un exemplu adițional despre testarea unui nou medicament pe șoareci pentru a reduce dimensiunea tumorilor cerebrale, subliniind componentele cheie ale unui experiment. Sunt îndemnați studenții să gândească logic în cadrul experimentelor pentru a răspunde la întrebări legate de colectarea datelor.

الوجبات الجاهزة

  • 🔬 Designul experimental investighează relațiile cauză-efect prin variabile.
  • 📊 Masa de zinc și schimbarea temperaturii: un studiu practic de variabile.
  • 📐 Variabila independentă influențează variabila dependentă într-un experiment.
  • 🔒 Menținerea constantă a unor variabile garantează validitatea rezultatelor.
  • 🐭 Un grup de control necesar pentru validarea efectelor observate.
  • 🎯 Grupul de cercetare exemplează impactul unui tratament asupra tumorilor.
  • 💡 Interpretarea graficelor: variabila independentă pe axa x, dependentă pe y.
  • 🧪 Exemplele practice încurajează gândirea logică în designul de experimente.
  • 📚 Practica cu întrebări ajută la înțelegerea concepțiilor experimentale.
  • 📝 Întrebările de design experimental implică adesea colectarea strategică a datelor.

الجدول الزمني

  • 00:00:00 - 00:05:40

    În această sesiune, vom revizui și învăța despre designul experimental. Ne uităm la un tabel de date cu 5 încercări, masa de zinc în grame, volumul de HCl în mililitri, presiunea atmosferică și schimbarea de temperatură. Observăm că masa de zinc se schimbă, însă volumul de HCl și presiunea atmosferică rămân constante, în timp ce temperatura variază. Vom asocia aceste observații cu conceptele de variabilă independentă (ceea ce schimbă cercetătorul) și variabilă dependentă (efectul observat). În acest context, masa de Zn este variabila independentă și schimbarea de temperatură este variabila dependentă.

الخريطة الذهنية

Mind Map

الأسئلة الشائعة

  • Ce sunt variabilele independentă și dependentă?

    Variabila independentă este variabila pe care cercetătorul o schimbă, iar variabila dependentă este efectul pe care cercetătorul îl observă.

  • Ce rol au variabilele constante într-un experiment?

    Variabilele constante sunt cele care rămân neschimbate în timpul experimentului pentru a asigura că orice schimbare în variabila dependentă se datorează doar variabilei independente.

  • Ce este un grup de control și de ce este important?

    Un grup de control este un set de subiecți de testare care nu primesc variabila independentă pentru a verifica dacă schimbările observate sunt datorate variabilei independente și nu altor factori.

  • Care este diferența între grupa experimentală și grupa de control?

    Grupa experimentală primește variabila independentă pentru a vedea efectele sale asupra variabilei dependente, în timp ce grupa de control nu primește variabila independentă pentru a compara rezultatele.

  • Care sunt variabilele identificate în exemplul cu zinc și HCl?

    Masa de zinc în grame este variabila independentă, iar schimbarea temperaturii este variabila dependentă. Volumele de acid clorhidric și presiunea atmosferică sunt variabilele constante.

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التمرير التلقائي:
  • 00:00:00
    Hello, students! In this session we're going to review and learn a little bit
  • 00:00:05
    about experimental design! So let's get started. Here's a data table and what
  • 00:00:11
    do we see here? Well, I see that there are five trials.
  • 00:00:14
    And then I see mass of Zn in grams. Zn is actually zinc, but even if you
  • 00:00:20
    don't know that, that's okay. Grams is a solid. Volume of HCl in milliliters is
  • 00:00:27
    probably a liquid. That's hydrochloric acid, by the way. Room pressure in atm,
  • 00:00:32
    whatever that is. And then the change temperature in Celsius. Now if I look at
  • 00:00:38
    the data really quick, I see that the mass of zinc is changing.
  • 00:00:41
    The volume of the hydrochloric acid is not.
  • 00:00:45
    The atmospheric pressure and the room is staying the same.
  • 00:00:49
    And then the change in temperature is changing.
  • 00:00:52
    So let's just keep that in mind for now.
  • 00:00:55
    Now, let's review a few concepts about scientific experiments.
  • 00:00:59
    We have, first of all, the independent variable. This is what the
  • 00:01:03
    scientist changes, ok? And then he or she is observing for something... to see if
  • 00:01:10
    A causes B. If the independent variable causes a change in the dependent
  • 00:01:16
    variable, which is the effect. So independent is a variable.
  • 00:01:21
    Dependent is the effect. The dependent always depends on the independent.
  • 00:01:26
    In any scientific experiment, there will be lots of
  • 00:01:31
    constants or controlled variables, ok? That means that you keep everything else
  • 00:01:36
    constant, or the same, except for the independent and dependent variables.
  • 00:01:41
    And then also a lot of times you have a control group, which is a group that does
  • 00:01:46
    not receive the independent variable to make sure that any changes that you
  • 00:01:51
    see in the dependent variable are not random changes are caused by something
  • 00:01:56
    else that you're not thinking about. So, let's look back at our data table and
  • 00:02:03
    see if we can figure out these different types of variables. If I'm looking at
  • 00:02:07
    this data table, even if I don't have a description what's going on, I say that
  • 00:02:13
    we're putting zinc and HCl together,
  • 00:02:17
    then we're trying to see if the temperature changes. Because it's
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    not very likely that a temperature change is going to change the mass in
  • 00:02:25
    grams of Zn. So the mass of Zn is going to be our independent variable.
  • 00:02:34
    What's going to be our dependent variable? What's the thing that changed
  • 00:02:37
    that we were probably observing for? That would be the change in temperature.
  • 00:02:43
    And then what were the things that were controlled, that we kept constant?
  • 00:02:48
    Well, that was the volume of hydrochloric acid and the atmospheric pressure in the room.
  • 00:02:52
    Everything was kept constant, so that we could see if we added more zinc to the
  • 00:02:58
    acid, would it change the temperature of the acid? And we see in this case that it does.
  • 00:03:06
    So here is the same data but in a graph form.
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    One thing to remember about graphs
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    is that the independent variable
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    is always on the x-axis
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    and the dependent variable is on the y axis.
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    Here is an example.
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    Let's try this out. Researchers test if a new drug will decrease the size of
  • 00:03:31
    brain tumors in mice. What's the independent variable here? What are the
  • 00:03:37
    researchers doing? Well, they're trying to administer or give this drug--
  • 00:03:43
    this tumor-preventing drug. The drug is the independent variable.
  • 00:03:49
    What are they observing for?
  • 00:03:51
    To see if this works. Is the size of the brain tumors
  • 00:03:56
    changed as a result of the drug? What are things that we have to keep constant the
  • 00:04:00
    whole time. Well, there are many, but for example: the species of mice, the food and
  • 00:04:04
    water they have,the environment that they are in, and the amount of drug
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    administered. You can't give one massive ton and one a little bit and
  • 00:04:13
    hope for the same results. Unless you want to test the amount of drug
  • 00:04:19
    administered. So that would be an independent variable, but as the sentence
  • 00:04:23
    is shown its it should be a constant. Then a control group is a group of
  • 00:04:30
    mice that do not receive the independent variable. This way you can know about
  • 00:04:37
    whether or not a change in brain tumor just happens randomly, or it's just
  • 00:04:40
    happening because of something else.
  • 00:04:44
    In the ACT you'll see those kinds of
  • 00:04:47
    questions that we just went over, but some other kinds, as well, that have to do
  • 00:04:51
    with experiment experimental design. Sometimes you'll be asked a question
  • 00:04:55
    about what's the best way to collect the data in this experiment. There's really
  • 00:05:00
    no way to prepare for that except to practice and to get used to thinking
  • 00:05:04
    logically about what they're doing in the experiment that you're presented.
  • 00:05:10
    As we do practice problems later on you'll encounter some of these questions
  • 00:05:14
    and you'll have practice in this type of thinking. The next t hing that
  • 00:05:20
    you're going to do now... There are some questions in a Google form that you're going to try.
  • 00:05:26
    These questions, for experimental design, are not ACT released
  • 00:05:30
    questions. Later on, we'll move on to the ACT released questions but for now
  • 00:05:35
    we're just practicing a few questions so you can really get this under your belt.
الوسوم
  • design experimental
  • variabile independente
  • variabile dependente
  • variabile constante
  • grup de control
  • experiment științific
  • măsurători
  • analiză date