12. Scientific Investigations
Success Criteria
Your learning has been successful if you can do the following:
Identify the main steps of a 'Scientific Investigation'
Define the terms 'Independent Variable', 'Dependent Variable' and 'Control Variable'
Be
Vocabulary
Learn these so you can communicate this concept well.
Average speed: Calculated by the total distance travelled divided by the total time taken for the journey.
Gradient / slope: How steep a line on a graph is.
Speed: How fast an object is moving.
Velocity: Similar to speed, but also tells us the direction in which an object is moving. It includes both speed and direction of motion.
Do Now:
Collect and complete this small 'Do Now'. Then glue into your SciPAD page 11. Use your commonsense when glueing - don't glue straight on-top of words!
Find some space on page 15 of your PESS1.2 SciPAD,
and answer the following questions:
What does each letter in CUTLASS stand for?
What do Scientists do? What is a Scientific Investigation?
Scientists ask questions to help work out what is happening in ther natural world around them. They then create testable ideas which they think may answer the question.
Scientists test their ideas by predicting what they would expect to observe if their idea were true (called a hypothesis) and then seeing if that prediction is correct.
Scientists look for patterns in their observatio and data.
Analysis of data usually involves putting data into a more easily accessible format (graphs, tables or by using statistical calculations).
The process of creating a question, developing a hypothesis and carrying out a test to collect data which is then analysed to see if their hypothesis is proved or disproved is called a 'scientific investigation'.
Fair Tests Only Change ONE Variable
Is this a 'Fair Test'? Why or Why not?
I want to find out whether a particular energy drink improves athletic ability.
I run a 100 m sprint without having the energy drink and time how long it takes. Then, I take the energy drink and run the same distance (100 m) and time how long it takes.
This is not a fair test because there are several variables that are not controlled.
Running another 100m immediately after running 100m, no rest break.
Running immediately after drinking the energy drink; drink may not have been digested/absorbed yet.
Weater in the first run may not be the same as the weather in the second run.
VARIABLES are all the things that could change during an investigation.
You should only change one thing at a time in your investigation. This is called the INDEPENDENT VARIABLE.
You should be able to measure something changing which is called the DEPENDENT VARIABLE.
The factors you keep the same in your experiments (fair test) are called CONTROL VARIABLES.
E.g. In a bouncing ball investigation, where the height a ball bounces to to is measured after it is dropped at different heights, many things could affect the results from one experiment to the next such as using a different ball, a different drop height or a different surface which the ball is dropped on. Identify the three different variables.
Identify the independent variable and dependent variables in the following scenarios:
An investigation to see which variety of tomatoes gave the most juice to make ketchup.
independent variable: variety of tomatoes
dependent variable: volume of tomato juice
The concentration of acid and the length of time it takes to break down a piece of metal.
independent variable: acid concentration
dependent variable: length of time taken to break down metal
How a person’s heart rate is affected by the number of cigarettes that they smoke.
independent variable: number of cigarettes smoked
dependent variable: heart rate
Parts of a Scientific Investigation
AIM (focus question): What you are trying to find out or prove by doing the investigation.
HYPOTHESIS (prediction): What do you think you will find?
METHOD: Simple, clear steps of what you will do – and how it will be repeated by another person (specific, clear, concise).
RESULTS: Data, tables and graphs collected from investigation.
CONCLUSION: What your results tell you – linked back to the aim.
DISCUSSION: Science ideas to explain your results, possible improvements to the investigation, how you managed to control the other variables and why (to ensure reliability).
Click through these slides to find out more about each part.
