Chemistry Design Lab Length?

[Guest Humaira]

this is my first practise IA which is not marked.

the question my teacher gave us is :

What kind of experiment could be performed to test the law of conservation of mass?

ok ive figured out what i will be doing which is vinegar and baking soda and the variable that will be changed is the temperature of the vinegar.

i was wondering how long should this design lab be? 1-2 pages? how much should i write for the variable portion?

also what is exactly is the data collecting portion? is it the quantity of each material, the temperature, the mass etc?

Edited March 22, 2012 by Humaira

[Procrastination]

Your teacher is supposed to give you a more concise question. I mean, since it's a Design Lab, despite the fact that it's just practice, your teacher should give you a question in which you should find the independent variable. For example in physics:

• Study one factor that affects the time taken by a parachute to fall from a determined distance. Hence, dependent variable: time taken to fall. Independent variable: something you should create, for example, holes in the parachute.
  
• Study one factor that affects the depth a crater made by a falling metallic sphere. Dependent varibale: depth of the crater. Independent variable: Mass?
  

Talk to your teacher ask him to specify things a little bit more, it's what's required by the IB. Show him some evidence.

Edited March 20, 2012 by Procrastination

[Summer Glau]

Well we can't think of ideas for you, I'm afraid. That you must do on your own.

The vinegar and baking soda idea...I don't really see how you'd be testing conservation of mass...if you use different quantities of baking soda, then the mass for each trial you do will be different, so you're not really conserving mass.

Try doing a Google search to find ideas though, it can be surprisingly helpful!

[Stanislaw]

No the conservation of mass via baking soda and vinegar is just, provided your erlernmeyer is hermetically sealed.

The idea is that you're mixing one liquid and one solid, converting them into different forms [gaseous + other] ; all the while your erlenmeyer still has the same weight, despite the products inside having changed state.

[Tony Stark]

Mine's 15 pages, and none of the predicted 7's at our school did less than 6-7 (the formatting of mine alone probably added 2-3 pages to the length); though I've noted labs in Australian schools seem to have quite a few more sections than their American counterparts.

The dependent and independent variables should be stated each in one short, concise section. The controlled variables section is the hard part, as you have to list all the variables you're controlling, why they need to be controlled, and how you're controlling them. It's really quite imaginative in nature.

The data collection portion may involve start and end masses (with mass change being the processed data); however this would be a quite weak DCP section.

I agree with Procrastination in that the question isn't particularly great, though I don't think it's conciseness that's the issue as much as it simply doesn't lend itself to a method for processing data. Our teacher gives us horribly broad topics, such as 'Catalysts' or 'Kinetics', however all the RQs I've formed (since I actually learned how to do IAs, 2 months into IB2..) follow the pattern of 'how does a change in X affect Y, as measured by Z?', with the magnitude and nature of change being specific. They in one sentence state the IV, DV and method for DCP. As for the 'as measured by' part, I usually explain why I chose that method of measurement in my background theory section, along with my hypothesis.

Edited April 12, 2012 by Tony Stark