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As promised in the Cell Transport section we are going to be doing an internal assessment based on the Osmosis process. It's nicknamed "Making Chips" = about exploring how not to let your potato chips go soggy before you fry them up.
Achievement Standard Biology 91153: Carry out a practical investigation in a biology context, with supervision
Resource reference: Biology 2.1
Resource title: Making Chips
Credits: 4
Step 1 : It is a full on proper practical investigation = you'll need to be familiar with what the Scientific Method is all about. There is a really good section in your Internals workbook. You should work through this first to remind you self about the key parts of the scientific method and what you need to be doing at each stage.
Key things to understand are : The Purpose = Aim and Hypothesis - why are we doing this and what do we think will happen. The Method (includes the different Variables - independent, dependent, controlled) = the recipe of how to do the investigation - anyone should be able to read your method and repeat your expt. The Results = the numbers/data/tables/graphs collected and created. Finally the Conclusion that explains what the results mean and links to your Purpose - aim/hypothesis. Then the Discussion in which we use the science of what is going on to interpret the results, you should include results from others to compare with your own findings/hypothesis. And an Evaluation where we look at the accuracy of our investigation, any changes we needed to make either during or for next time and why, was our data valid = consistent with any trials.
I did make a video for students at Year nine to introduce them to this = I've included it here as it is a good place to start. (Learn)
Mission 1 : Work your way through the pages in your internals work book on the Scientific Method. (Learn)
Done that? = Share with your teacher.
Yes = now its time for your next Step/Video clip/Challenge/Mission.
No = go back and complete the Step/Video clip/Challenge/Mission please.
Challenge 1 : We are going to carry out a trial run = practice what we need to be doing in the internal investigation.
You could use these results in your evaluation to help with your discussion and evaluation.
We are going to use the practical as laid out in your externals workbook on "Observing the Effects of Tonicity on Tissues". But with 2 slight changes = we'll be using carrots and salt solutions - why - well we'll use potatoes in the actual investigation and salt solutions don't go "rotten" with time.
Use this also as a way of figuring out - what is a valid range? and how do we ensure our results are valid?
As part of your results you have to process your data from a table into a graph (a graph is a "picture" of the numbers). How do you do that - watch this to help you.
Before you write your conclusion remind yourself what is going on by re-watching the following clips. (Learn) (Create) (Share)
Done that? = Share with your teacher.
Yes = now its time for your next Step/Video clip/Challenge/Mission.
No = go back and complete the Step/Video clip/Challenge/Mission please.
Step 2 : Its time for the real deal = here is your next internal assessment.
Included is a copy of the actual assessment = your teacher should give you a copy.
BUT listed below are the key stages - with key points in Bold - check in after each stage to make sure you are on track.
(Learn) (Create) (Share)
2.1 Student copy WTE version.docxLets get started :
This assessment activity requires you to produce a Biological Report on the the process of osmosis using potato chips soaked in different salt solutions.
As part of the assessment you are required to:
· individually plan your investigation and submit your plan to your teacher for feedback
· process and interpret your data and report on the investigation individually
· interpret your findings with relation to another source, after considering and comparing them with the whole class or findings from scientists relevant to osmosis.
You will have access to your portfolio of biological ideas and concepts learned during the teaching of the topic as you write your report.
Task
Task
Plan your investigation
Note: You have one period of class time to complete this individually.
Based on your knowledge of osmosis, and the resource material provided, develop and carry out an investigation into the process of osmosis using potato chips soaked in different salt solutions.
The following equipment is available:
Potatoes, knife (or cork borer), distilled water, weighing balance, containers, lids, gladwrap, paper towels, a range of salt solutions (0.1 mol L-1, 0.2 mol L-1, 0.3 mol L-1, 0.4 mol L-1, 0.5 mol L-1, 0.6 mol L-1, 0.7 mol L-1, 0.8 mol L-1, 0.9 mol L-1), other normal lab equipment, such as thermometers, glassware, hot and cold water and resource material covering the essential biology needed for the activity.
Don't forget the following .....
To Complete your draft plan, it should include:
A purpose for your investigation, written as an hypothesis linked to osmosis.
A detailed step by step method on how to collect your data by considering:
· the range over which the independent variable will be changed
· how the dependent variable will be measured
· the control solution you will use
· What other variables and factors (outside the Independent and Dependent Variables) will you be controlling and WHY. (at least 2)
· how you will ensure your results are accurate, valid and reliable
Watch the following first = they will help.
Hand in your plan in to your teacher for feedback.
Write your group plan
Based on your individual plans, your teacher will put you into groups to collect your data.
Discuss your individual plans and decide on a shared plan.
Write and submit your group plan for feedback.
Trial your investigation method, then use the information you found out in your trial to develop it into a step by step method. Write out your final method in your Biological Report.
The carrot osmosis practical was your trial = you should be able to use what you've learned from that and the videos to create your group step by step method
( I should be able to give your method to another class and they shouldn't need to ask for any clarification to be able to do the practical)
Done that? = Share with your teacher.
Yes = now its time for your next Step/Video clip/Challenge/Mission.
No = go back and complete the Step/Video clip/Challenge/Mission please.
Collect and record your data
Note: You have 1–2 periods of class time to complete this.
In your assigned groups, carry out your investigation and collect and record your data. While the group may work together to collect the data, you must each record your own data.
Record data and observations relevant to your investigation in an appropriate way.
You may amend your method as you carry out your investigation. Make sure you record all of these changes.
You'll need to mention these changes (if there are any) in your Evaluation later.
Done that? = Share with your teacher.
Yes = now its time for your next Step/Video clip/Challenge/Mission.
No = go back and complete the Step/Video clip/Challenge/Mission please.
Process your data and report your findings
Note: You have 1 – 2 periods of class time to complete this individually.
Process your data to produce results that can be compared directly with each other (% change in mass) i.e. to enable a trend or pattern (or absence) to be determined, and with other sources of information.
Graph the processed data in a way that allows you to interpret whether there is a trend in the data.
Done that? = Share with your teacher.
Yes = now its time for your next Step/Video clip/Challenge/Mission.
No = go back and complete the Step/Video clip/Challenge/Mission please.
Use the processed data, observations and measurements you recorded to write a well-organised a Biological Report on your findings that includes:
This is what you've done so far.
a statement of the purpose of your investigation written as a hypothesis linked to osmosis
a detailed account of the final step by step method you used
recorded data and observations
processed data presented in a table and graph appropriate to the type of data collected
This is the checklist for your Conclusion/Discussion/Evaluation.
State how your findings support your hypothesis. This forms your conclusion.
· Provide evidence from another source that supports your hypothesis.
· Using the correct scientific terms, discuss what your findings suggest about the Biological Ideas relating to Osmosis.
How do these ideas relate to other organisms.
· State the things that you did that ensured validity, accuracy and reliability of your findings.
· State the things that you did (or did not) do that, contributed sources of error, plus the limitations of your findings
· If you were going to repeat this investigation, what would you do differently and WHY
Done that? = Share with your teacher.
Yes = now its time for your next Step/Video clip/Challenge/Mission.
No = go back and complete the Step/Video clip/Challenge/Mission please.
So ..... how DO you stop your chips from going soggy ????
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