Scientific Method

Science – an organized way of using evidence to learn about the natural world.

1.) State the Problem- something you can't explain- well defined- only 1 at a time

2.) Collect Information- research, observation – may lead to an inference = logical interpretation based on prior knowledge or experience

- leads to informed hypothesis- someone may have already solved the problem!

3.) Form Hypothesis- proposed scientific explanation about a set of observations- MUST BE TESTABLE!!!- may have more than one hypothesis for a certain problem

4.) Experiment- used to test hypothesis- use a control to have a frame of reference

Manipulated (Independent) variable - variable that can be controlled by the experimenter

Ex: time, depth, temperature

Responding (Dependent) Variable - what factor changes (what you are testing)- variable that is directly affected by the independent variable

Ex: How hot water gets depends on how long it sits in a teapot over a fire

* Sometimes it is not possible to do an experiment due to ethical concerns.

EX: Chemical testing on humans, wildlife interactions

- in this case, scientists try to eliminate variables and then conduct and observational experiment

5.) Compile Data/ Analysis - keep written results and then analyze them to help come to a conclusion

6.) State the Conclusion - was your hypothesis proven or disproved?

Theory- well tested explanation that unifies a broad range of observations

Law -something that has been observed to be so - results are always the same

Tools, Measurement, and Safety1-4

Tools for science: ~ Computers

*technology allows us to: ~create graphs ~collect data ~solve equations ~share ideas and data ~publish research

~ Microscopes-

All microscopes have the ability to * magnify -- make something appear larger * resolution -- ability to distinguish small, close objects.

2 types: a.) LIGHT MICROSCOPE - uses a beam of light through 1 or more lenses

* What we use in lab! -- compound microscope

* can observe living and non-living things

* drawback: as magnification increases, resolution decreases!

b.) ELECTRON MICROSCOPE - uses e- instead of light to form images

* can see up to 100x more than light microscope!

* can observe dead cells only!!

Check out this close up of pollen!

SEM and TEM

Scanning Electron Microscope - specimens coated with metal- mag. up to 100,000x- 3D image

Transmission Electron Microscope - specimens sliced and stained

- mag. up to 200,000x

Measuring

SI - International System of Units ~ the official name for the metric system ~ works with powers of 10

Can measure a variety of ways:

~Length~Area~Volume~Mass~Temperature

Length:

~ Uses millimeters, centimeters, meters, and kilometers

~ For even smaller things, there are micro and nanometers!

*Which would you use to measure an ant?

*The distance from your house to Indiana?

*The length of a dollar bill?

Area -

~ How much surface an object has

~ measure length and width to determine area

~ stated in square units

ex: m2 cm2 km2

Volume ~ measure of the size of something in 3D space

~ most often described in Liters (L)

~ is given in cubic units

ex: cm3 or mm3

Can be found by multiplying length x width x height

1 mL = 1cm3... in other words, 1 mL will fit into a box that is 1 cm on each side

Another way to measure irregular shaped objects is to measure water displacement...

ex: find the volume of a rock...

Mass - the amount of matter in an object

~ kg is basic unit

~ one metric ton = 1,000 kg

may also use...grams (g) to measure small objects!

ex: a medium apple has a mass of about 100g

~ can use a scale or balance to measure this!

Temperature - measure of how hot or cold something is~actually , it's how much energy within the matter...

Cold = low energy Hot = high energy

~ can be measured using either oF or oC but Kelvin (K) is the official unit for temp!

celsius farenheight

Some things you should know...

Freezing is at 0oC or 32oF Boiling is at 100oC or 212oF