What happens in a fair test investigation?
For a fair test investigation, you will change one variable and measure the effect it has on another variable, while keeping everything else the same. You will be given an aim and an equipment list. Using the two, you are expected to construct a purpose, method (by yourself) and carry it out (as a group) in order to come to a conclusion. You will gather and process data from your investigation and discuss the scientific ideas that have produced your results. You also need to evaluate how valid your method was and how reliable your data is. This is done individually, in class time, as a written report.
The only thing you do in pairs is the carry-out part of the investigation.
The only thing you do in pairs is the carry-out part of the investigation.
You will be given a template to guide your thinking and help you gather ideas throughout your investigation.
You aren't doing this alone and you can ask questions! |
What do I need to do in an investigation, and how do I do it?
There are many parts to an investigation. They are listed below.
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You will have 5 class periods to complete your investigation.
Below I have detailed how to do the 9 things above based on the day you should be doing them :)
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Variables
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Aim/purpose
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Hypothesis (A)
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Method (A/M)
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Spend two minutes identifying the different variables from the purpose you're given. This will help you as you plan your investigation.
Independent variable |
Dependent variable |
Controlled variables |
The variable you change. I change it |
The variable you measure. It depends on me to measure it |
All the variables you control so they do not impact/influence your results. I control these (You will take all of these into account as you write your method) |
For example, I am looking to see whether the height at which I drop a basketball affects how high it bounces.
- My independent variable is the height at which I drop the basketball from.
- The dependent variable is the height of the bounce.
- The controlled variables might be the type of ball, the ruler used to measure the height the ball was dropped from, the same person measuring the height of the bounce in the same way.... etc.
You are often given one of these, but may be required to write one yourself.
An aim is a statement about your investigation. It mentions both your variables (independent and dependent). Your aim either answers the question "what do we want to find out?" or finishes the sentence "we are going to investigate how..."
An aim is a statement about your investigation. It mentions both your variables (independent and dependent). Your aim either answers the question "what do we want to find out?" or finishes the sentence "we are going to investigate how..."
For example, I am going to investigate how changing the height at which a basketball is dropped affects the height of its first bounce. If I were to say 'I am going to investigate how height affects the bounce of a basketball' - I haven't actually mentioned my dependent variable (i.e. what is actually measured) so my purpose would not be good enough.
A hypothesis is an educated guess about what your trend will be like when you collect your data. It's 100% fine if your hypothesis is incorrect after you've carried out your experiment (i.e. your results don't agree with it) as this gives you things to talk about later in your discussion. All you are doing is taking an educated guess at what your results would look like, and give a reason for why you think so.
Your hypothesis must include your dependent and independent variables, what you think will happen, and a brief reason why. Don't go into depth with the science here, save it for your discussion (it's the science section!). Your hypothesis needs to be specific - not "more x will make abc grow taller" but "as the amount of x increases, so will the growth of abc" or "I predict that x amount of yz will cause abc to the tallest". Something along those lines, but with a brief reason too.
Your hypothesis must include your dependent and independent variables, what you think will happen, and a brief reason why. Don't go into depth with the science here, save it for your discussion (it's the science section!). Your hypothesis needs to be specific - not "more x will make abc grow taller" but "as the amount of x increases, so will the growth of abc" or "I predict that x amount of yz will cause abc to the tallest". Something along those lines, but with a brief reason too.
For example, I hypothesize that as the height at which the ball is dropped increases, so will the height of its first bounce. This is because the basketball would have more gravitational potential energy so when let go, more force will be present and thus creating a taller bounce.
On day one, you will start writing your method. This is not going to be precisely what you do when you carry it out, but it is a starting point. You will get to discuss aspects of your method with your partner so that you both carry out the same method however you need to have one drafted up to do so.
Your method is a set of instructions that, when followed exactly, would give the reader results very similar to what you got.
Your method is a set of instructions that, when followed exactly, would give the reader results very similar to what you got.
- Your method must be clear, use correct scientific terms and include units for all your variables (IV, DV, CVs)
- Your method must be quantitative - use exact numerical values (i.e. instead of "add a little bit of water' you would say "add x mL of water".
- Your method should include ways to control all other variables. The person following your method should be able to make sure nothing else can affect the results except for the independent variable.
- Your method should be clear enough that someone that doesn't know or do science can follow it.
Write notes to yourself on your instruction booklet - remind yourself to include UNITS for all your variables. No joke, if you don't include these then you will get a Not Achieved (not our choice, it's in the standard!).
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Method (A/M)
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Recording data (A)
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Processing data (A/M)
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On day two, you'll be carrying out your method so you need to jot down any changes/details that are important so that you don't forget them. You can add them to your final method so that it is precisely what you did!
Remember, your method is a set of instructions that, when followed exactly, would give the reader results very similar to what you got.
Remember, your method is a set of instructions that, when followed exactly, would give the reader results very similar to what you got.
- Your method must be clear, use correct scientific terms and include units for all your variables (IV, DV, CVs)
- Your method must be quantitative - use exact numerical values (i.e. instead of "add a little bit of water' you would say "add x mL of water".
- Your method should include ways to control all other variables. The person following your method should be able to make sure nothing else can affect the results except for the independent variable.
- Your method should be clear enough that someone that doesn't know or do science can follow it.
- Use a table to gather your raw data (the data you get from measuring your dependent variable during your experiment).
- Include units!
- Be consistent. If you realize halfway through that you're measuring from the wrong point, you have to make a call - as changing may disrupt your data. Instead you might change your method to account for this.
- Take any notes/observations that you come across as these could come in handy for your discussion.
- You may add to your existing table or construct a new one (you don't want to waste your time making a new one if you're running out of time!) - to calculate averages (add all values together then divide by the number of values you've just added)
- Include appropriate units and a title for your table - ensure your title contains both your variables!
- Graph your averages if you'd like to. If your table shows a clear trend then graphing is not necessary. Graphs can make results easier to interpret.
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Processing data (A/M)
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Conclusion (A/M)
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Discussion (M/E)
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- You may add to your existing table or construct a new one - to calculate averages (add all values together then divide by the number of values you've just added)
- Include appropriate units and a title for your table - ensure your title contains both your variables!
- Graph your averages if you'd like to. If your table shows a clear trend then graphing is not necessary. Graphs can make results easier to interpret.
- A conclusion must relate back to the aim/purpose of the investigation. In it you need to say whether you reject or acceptyour hypothesis.
- Back up your statement with some of your processed results. Look at them... what can you conclude?
- This should only be a few sentences long (no more than 5!)
You may have time to start your discussion on Day 3!
Here's where the science comes in. This section is your attempt to explain the results you obtained using scientific/biological ideas.
You are explaining what has happened scientifically during your investigation. This will all relate to the content learned in class.
A good way to structure your discussion is in paragraphs.
You can also state what has gone wrong (if anything) and why - and how this impacted your data. What did you think should have happened instead?
- The ball dropped from _cm had the highest bounce of _cm... (reason)
- Result y was different to z because ... (reason)
You are explaining what has happened scientifically during your investigation. This will all relate to the content learned in class.
A good way to structure your discussion is in paragraphs.
- Set the scene
- Discuss one average (i.e. the shortest or slowest or...?) - Introduce the data, compare it to the rest of your averages, give a scientific reason for it, relate to the main concept of the investigation.
- Discuss another average, do the same as above
- Discuss another average, do the same as above
- Mention your hypothesis again and reaffirm your conclusion
You can also state what has gone wrong (if anything) and why - and how this impacted your data. What did you think should have happened instead?
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Discussion (M/E)
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Evaluation (E)
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Here's where the science comes in. This section is your attempt to explain the results you obtained using scientific/biological ideas.
You are explaining what has happened scientifically during your investigation. This will all relate to the content learned in class.
A good way to structure your discussion is in paragraphs.
You can also state what has gone wrong (if anything) and why - and how this impacted your data. What did you think should have happened instead?
- The ball dropped from _cm had the highest bounce of _cm... (reason)
- Result y was different to z because ... (reason)
You are explaining what has happened scientifically during your investigation. This will all relate to the content learned in class.
A good way to structure your discussion is in paragraphs.
- Set the scene
- Discuss one average (i.e. the shortest or slowest or...?) - Introduce the data, compare it to the rest of your averages, give a scientific reason for it, relate to the main concept of the investigation.
- Discuss another average, do the same as above
- Discuss another average, do the same as above
- Mention your hypothesis again and reaffirm your conclusion
You can also state what has gone wrong (if anything) and why - and how this impacted your data. What did you think should have happened instead?
You need to justify your findings - how can you, your method and your results be trusted?
- Why is your investigation valid? - How is this a fair test? How did you ensure there is no bias? What did you control and why? What would happen if you didn't?
- Why is your data reliable? - Could similar results come from someone copying your method? Are your results just a one-off? How can you be sure? Did you do repeats? Why? Did you calculate averages? Why? Did you remove outliers? Why?
A good structure is something like
Remember this is where you can get an E, so there needs to be sufficient depth to your thinking and most definitely some science in there!
- I controlled x
- I controlled x by doing...
- By controlling x it ensured that.... (relate to results & science)
- If I didn't control x then ... (relate to results & science)
Remember this is where you can get an E, so there needs to be sufficient depth to your thinking and most definitely some science in there!