How science works 

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When carrying out experiments and answering questions based on interpreting experiment you need to know the following.  

The independent variable is what is changed during an experiment
  Remembering Tip: Independent starts with I so it is the variable that I change. we plot the independent variable along the x-axis .

 The dependent variable: is what you measure in the experiment i.e. the results.
 Remembering Tip: DRY ... D for dependent , R dependent means result  ,  Y .. we have to plot it along the  y-axis

The control variables:  are the things you want to keep the same during an experiment. 

When plotting a graph for your results you generally  plot the dependent variable along the y-axis and the  independent variable along the x-axis.  

During experiments we repeat measurements to make the results more reliable.  

Your independent/dependent variable can either be continuous or Categorize.
 Continuous variables are numbers 1.2, 5.76, 3.0 etc – draw a line graph
 Categorize variables are categories e.g. colors, metals – draw a bar chart  

Describing results 
· This graph is showing a positive correlation, i.e. as one variable increases so does the other and the line goes up. · A negative correlation is when one variable goes up the other goes down, the line would go downwards.   

During experiments we repeat measurements to make the results more reliable.  

Line of best fit

A line of best fit is usually drawn on a scatter diagram. It is drawn so that the points are evenly distributed on either side of the line.

When drawing the line of best fit, use a transparent ruler so that you can see how the line fits between all the points before you draw it.

Scientific investigation 


Scientific investigation is a quest to find the answer to a question using the scientific method. In turn, the scientific method is a systematic process that involves using measurable observations to formulate, test or modify a hypothesis. Finally, a hypothesis is a proposed explanation for some observed phenomenon, based on experience or research. Scientific investigation is what people like you and me use to develop better models and explanations for the world around them.

Steps for Scientific Investigation

As you can imagine, there are several phases to a good scientific investigation. These may vary a bit in the literature, but they generally include the following:

The steps of the scientific method
Scientific method steps

Obviously there are a number of elements to each of these steps. Let's dig a little deeper.

Observation - thought

Step 1 - An Observation

The young man at the science fair obviously enjoyed playing with toy cars and had noticed that when he increased the pitch of the ramp, the cars went faster. He wondered what the relationship was between the steepness of the ramp and the speed of the car, beyond just the obvious fact that it went faster as the slope increased. People who engage in a scientific investigation usually do so because they don't know or are unsure of some aspect of the observation, or because they want to confirm a hunch about the observation.

                                                                                                                                                                                      observation is the first step


Step 2 - The Question

It's important to ask the question so that it can be answered in a measurable way. 

Question - chicken

Beginning the question with 'What', 'How', or 'Why' is a good start. 

The question should also be focused.

 Many researchers make the mistake of trying to 'boil the ocean' with a question that is too general. 

For example, 'Why do people get sick?' would not lend itself to a good scientific investigation in anyone's lifetime, even though it's a pertinent question. 

Remember: boiling the ocean is quite a bit more difficult than boiling a pot of water.

                            you have to ask the right question 


Step 3 - The Hypothesis                                                                                                                                             formulating hypothesis

Hypothesis - chicken                                                                                                                                                                                                             

You may be wondering, 'Why come up with a hypothesis about something we're trying to discover?' It's much easier to analyze data and compare it to an existing theory than to try to develop a theory from scratch. There are already good models for much of what we observe, so we can usually find the seeds of an answer to our question through research. Many times, scientific investigation is used just to make incremental improvements to a theory, process or product. So in short, the hypothesis brings to bear all that is already known about the question; it gives us context for what we're studying.

When I asked the young boy about his hypothesis, he said, 'When I play with my cars, I notice that when I start increasing the slope of the ramp, the speed of the car seems to change a lot. But later on, at the higher slopes, the car goes fast but each change seems to have less effect. My dad's a teacher and when I talked to my him about this, he said that the force of gravity goes straight down. So the part of gravity that is affecting my car changes with the angle, but it changes less at the higher angles. He said it has something to do with 'trigonometry.' I don't know what that is. Anyway, that's what I am expecting to happen.'


Step 4 - The Experiment

Experiments are affected by many variables
mad scientist

This is the fun part but is also the easiest step to mess up. Experiments are fraught with uncontrollable variables, bias, measurement error and other unintended consequences, so it's important to understand all these things and take them into account as much as possible. 


step 5 - Conclusion

What you have found out from the experiment