Lactose Intolerance Variables

[dtacy126]

Hi,
I'm a 7th grade student doing the "I Love Ice Cream But It Doesn't Love Me; Understanding Lactose Intolerance" experiment. Me and the people in my group have been researching information and we don't know what our Variables in the experiment are!
Please help us!
Thank you! We would really appreciate it, it would be a great help!

[MelissaB]

Hi,

Science Buddies has a great explanation of variables here: https://www.sciencebuddies.org/science- ... bles.shtml . I like to think of it that the dependent variable is the thing you measure, while the independent variable is the thing you change. Controlled variables are things that stay the same throughout the experiment but might affect the dependent variable (often room temperature is a control variable, for example, because it was the same in all trials.

Post back once you read Science Buddies' guide if you still have questions.

[dtacy126]

Hi again,
Thanks for the advice. A problem with our project is that we are not really sure whether it is fact based or not. Technically, of course, it is, but we are also doing an experiment. We understand it that the experiment is just demonstrating what we already know. Is that correct? Also, upon thinking more about it, we believe that lactase is the independent variable, and the glucose is the dependent variable. Is that right? Please let us know, as we want to make sure these things are clear before we go ahead with the experiment. We have already done our research and are preparing our background paper for our tri fold.

[MelissaB]

I am not sure what you mean by fact-based. There are lots of facts that are involved in this experiment. However, I do think I understand your reservations about the project. You are right; as written it is essentially a demonstration. So, you might instead want to do some of the 'variations' shown below the project. Or, you could do something that I would certainly be interested in--determine how much lactase you actually need in order to break down all the lactose (and therefore not have a bad reaction).

Glucose is indeed your dependent variable. I would make your independent variable a bit broader and say 'type of liquid', since you are not just looking at the presence/absence of lactase but also lactose free milk, water, and a glucose solution.

Good luck!

[dtacy126]

We have decided that we believe our project is fact-based and demonstrative, but that that's okay with us because we have already done the research on lactose intolerance and while the variations are very interesting, it would change our entire project. We do not think we could do two experiments; it might be too much on our our tri fold, because by itself the project does need a lot of information and parts on it.
I do have another question before we do the experiment though: Do the glucose strips recognize the glucose in the lactose in the milk before we add the lactase to it? I think that they don't. Basically, I know that the water and milk in the beginning is just making sure the strips work. But then, when we test the milk and lactose reduced milk, (if my assumption is correct that the glucose strips dont recognize glucose when its still in the lactose) isn't there not going to be glucose in either? Won't there only be glucose when we add the lactase?

[MelissaB]

You are correct: the strips only recognize free glucose, not glucose bound to another sugar molecule (as in lactose). So, if there is only lactose present, you should essentially get a reading of zero on your glucose monitor. Once that glucose molecule has been split from the galactose molecule, however, your glucose meter will pick it up. Thus, your hypothesis makes sense to me except for one small bit: I suggest you do a little bit more research on lactose free milk and how it is produced .

[dtacy126]

Thanks so much for that suggestion! So, after doing that research (and understanding that lactose free products are produced by adding lactase to the regular milk products), I have been trying to figure out what our hypothesis would be. I feel that the experiment is mostly demonstrating what the enzyme lactase does, so, I think that our hypothesis might be:
If lactase is added to solutions containing glucose, then we will be able to determine which solution contains a larger amount of glucose.
Please let us know if this is correct!

[MelissaB]

Hi,

Not quite--your hypothesis should predict exactly what you think you will measure. Here's Science Buddies' write up on hypotheses: https://www.sciencebuddies.org/science- ... esis.shtml . So, your hypothesis should be more along the lines of, "We expect glucose concentrations to be higher in

• than in
  • .
    
    Good luck--it should be a fun project!

[dtacy126]

We're sorry to keep bothering you!! But doesn't the hypothesis need to have "if" and "then"?

[MelissaB]

It depends--some teachers do require hypotheses to be if/then statements, yes. In that case, I would use something like, "If we add lactase to milk, then the glucose concentrations..."