Science Basics: Scientific Method, Experimental+Control Groups, Lab Tools, Key Concepts in Science and Engineering

The Scientific Method

1. State the Problem

2. Form a Hypothesis

3. Observe and Experiment

4. Interpret the Data

5. Draw Conclusions S

State the Problem

What is it they/you are trying to understand?

Form a Hypothesis

Why something works the way it does; an educated guess

Observe and Experiment

Determine the validity of that hypothesis

Interpret the Data

Does it support hypothesis or does it refute the hypothesis?

Draw Conclusions

If refutes, conclusion is hypothesis was not valid

If supports hypothesis, might further refine the hypothesis by further testing to improve the hypothesis

Just because the data supports the hypothesis, does not mean the research is over

Experimental Groups

A group of subjects upon which a hypothesis is tested.

Control Group

A group that resembles the experimental group in all other ways, but on which the hypothesis is not tested. (In some clinical trials, _____ groups are given a placebo.)

• This is to eliminate “false positives”

Might Ask you to Design an Experiment

Figure out which type of bacteria does better in moist environments.

Might say how would you design that experiment? What factors might you control for?

Experimental factor: a moist environment

• so fact you’ll change: the amount of water

Other factors that can make the bacterium do better

• the temp

• food supply

• the acidity or basic qualities of the fluid that’s in them

So how would I control for that?

• I need to create 2 environments that are exactly the same EXCEPT for the MOISTURE

2 side by side environments where the Temps same, acidity of fluid the same, food supply the same, only difference is the moisture

We will know if one does better than the other, in both experimental and control group it’s some other factor, but

If it only does better in the experimental group not the control group , then it relates to that bacteria’s response to moisture.

Beaker

For Containing fluids, not a real accurate measurement

Graduate Cylinder

More accurate measurement for fluids

• Longer

• More narrow

• Has more graduations on it, so each amount you add it to is going to cause a bigger representative change and give more accurate results

Bunsen Burner

Produces a controlled flame; often used to heat substances, sometimes to cause them to change states or a chemical reaction

Balance

Put something on one side, then you put little weights on the other side so it balances out

• that tells you the mass of something

• the nice thing about a balance is it typically doesn’t have to be calibrated

• take balance to moon or earth, the gravity will balance out on both sides so it will still give the same mass measurement regardless of environment

(Think scales of justice)

Scale

Works by a spring getting compressed by the pull of gravity against the scale so it has to be calibrated based on how much gravity is pulling down.

So will give a diff reading on moon than will on earth because the moon has less gravity to pull down.

(think one in bathroom)

Density

Destiny = mass/volume (How much stuff do you have in a certain amount of space?)

The more stuff you have in the same space, the DENSER that thing is. We need to find the mass and volume so we will know the density.

How could you find the mass of the marble?

• Using the Balance

  • Putting it on the balance, using some weights on the other side, you can find out how many grams the marble is

How could you find the volume of the marble?

• Displacement

  • Put water to a certain level in the graduated cylinder, about 100 milliliters, drop the marble in, and the water goes up to 150 milliliters; that displacement of the marble is 50 milliliters

  • The difference between where the water started and where it ended up.

Patterns

Observations can be used to describe phenomena

“when we observe this thing, we also see this thing.” Pattern developing

e.g. When we see lighting, we hear thunder (we do not know if these two things are casually related, but we do see correlation between them).

Cause and Effect

Empirical evidence is required, not simply correlation.

“people who eat thing X, have a higher rate of disease Y

Has this been studied empirically? Do we know that there’s a casual reason for that or is it simply a correlation we’re observing?

So it could be that people in the area where they eat that kind of food, are also exposed to some kind of a pollutant or something that they’re not aware of that could be causing that thing.

-So we don’t know until we research it in more depth.

(Trying to improve or disprove it.)

Empirical Evidence

Scale, Proportion, and Quantity

Observations are dependent on these factors and could have a major impact.

e.g. How does a droplet of water behave in a certain way does an entire bucket of water necessarily behave the same way as that single droplet?

We’d have to see it, it depends in what way were we’re asking.

Systems and System Models

How do components function together?

There’s different parts of a system that could be doing different things.

So different rocks that are part of the earth that are moving in a certain way when we are talking about the rock cycle. So there’s different components.

Energy and Matter

Energy cannot be created or destroyed, but drives movement/cycling of matter

e.g. rock cycle, thermal energy and gravity is causing these rocks to move around primarily

or if we’re talking about the water cycle, talking about solar energy from the Sun as well as gravity causing that cycle to move.

We’ll talk more about the details of these cycles in other sections

The important thing to understand is that the energy cannot be created or destroyed, but it’s driving the movement and cycling of matter within those systems.

-deep connection between energy and matter

Structure and Function

Often be inferred from each other (to understand each other)

e.g. never encountered an airplane before, but a scientist was looking at one, might be able to figure out what that device does by looking at the different parts of it and determining how it could move through the air,

likewise scientist look at fossil evidence and determine how. a creature would might have lived and how it might have moved through its environment by seeing how did the different parts fit together, how do these joints set, how would that affect the musculature

Stability and Change

Changes can occur gradually or quickly.

e.g. erosion over a long period of time; can change it from a flat plane to a valley or a canyon.

Other changes occur very quickly such as

• human action like oil spill can cause massive impact on an ecosystem

• natural thing like a giant impact hypothesis about why the earth has its moon is that a small planet sized body moving through the solar system billions of years ago impacted the earth and that impact caused them to begin to move around each other and that’s how the moon got in orbit