GCSE science: Working scientifically (copy)

what are the 3 stages of when i scientist comes up with a hypothesis ?

1. the scientist tests it
2. then multiple scientists will test it
3. if all the evidence supports it the hypothesis is accepted for now

what is the independant variable

the variable that changes

What is the dependant variable

the variable that is measured

what is the control variable

the variable that stays the same

What makes evidence valid ?

* it has to be repeatable
* it has to be repoducable

What is accurate data ?

data that is close to the true answer

What is precise data ?

when the data collected are all very close to each other and the mean

What is a random error ?

unpredicatbale differences in things such as human error and measuring.

What is a systematic error?

when a measurement is wrong by the same amount every time

repeating the experiment the exact same way will not correct it

What is a zero error ?

when equipment is not set to zero and has a reading before use

How can you solve a zero error ?

by noting the initial measurement and subtracting it from all your results at the end

What do you do with anomolous results

yu can ignore it when processing the results (e.g., a mean)

Define:

* mean
* median
* mode

* mean - add all numbers together and divide by how many results
* median - righting the numbers in numerical order and finding the middle number
* mode - find the value that occurs the most freuqent

how do you present categorical data ?

in a bar chart

how do present continuous data

in a line graph

What axis does the dependant variable go on ?

What axis does the independant variable go on ?

dependant - y axis

independant - x axis

How do you find out the gradient ?

change in y/ change in x

How do you find the gradient of a point on a curve ?

draw a tangent from that point on the curve and find out the gradient of the tangent

What does this graph show ?

Positive corrolation

What does this graph show ?

Negative corrolation

What does this graph show ?

No corrolation

What is the multiple unit for tera ?

1 x 10^12

What is the multiple unit for giga ?

1 x 10^9

What is the multiple unit for mega ?

1 x 10^6

What is the multiple unit for kilo ?

1 x 10^3

What is the multiple unit for deci ?

1 x 10^-1

What is the multiple unit for centi ?

1 x 10^-2

What is the multiple unit for milli ?

1 x 10^-3

What is the multiple unit for micro ? (μ)

1 x 10^-6

What is the multiple unit for nano ? (n)

1 x 10^-9

What do you do if you are going from a smaller to bigger unit ?

divide

What do you do if you are going from a bigger to smaller unit ?

multiply

how dyou figure out the uncertainty ?

range/2

What should yo include in a scientific evaluation ?

* is the method valid and a fair test
* quality of the results (repeatable, repoducable, accurate,precise)
* were there any anomolous results and which error caused them
* comment on the uncertainty
* suggest any changes to the method to omprove the quality of the results