Science Buddies: "Ask an Expert"

Dear science buddies,
I need some help with my research for my project "Do dogs prefer sweets, meat or vegetarian diets" I researched what dogs cannot eat in there diets but I need another research idea and I have to change one variable in the experiment. Can you help me. I was going to give my dog a choice of three foods and I have to have 3 trials.
thank you

Hello. A very interesting experiment! A few thoughts.

Are you asking about the meal preference or treat preference? When it comes to talking about diet for us or animals, we may PREFER sweets but it is HEALTHIER to eat meat and vegetables. When it comes to talking about diet, it is more important to concentrate on what is the healthiest to ensure the animal is getting the nutrients required to remain healthy. However, if we're talking about treat preference, we all have a sweet tooth. Some prefer candy and cake, others consider a carrot or a hamburger as a treat. Be sure to make this clear which one (diet or treat) that you are testing.

Variables.
1. Your first variable will be the diet type: sweets, vegetarian, or meat
2. You could do different time of day. Does the dog's preference change if you test right before or after he eats, half way through meals? Our blood sugar changes throughout the day based on what and when we have eaten. This could affect taste preference. If you are not going to use this as a variable, be sure to control it during your experiment. Meaning, always conduct your test at the same time of day (or more accurately, same time before or after a meal has been given).
3. Another idea is breed of dog. Do chihuahuas, golden retrievers, and german shepherds have the same preference? Again, if you're not going to use this as a variable, if you are going to use more than one dog (and you should try to), be sure to test the same breed of dog.

Research:
1. I am glad you have researched what dogs cannot eat, because they should not eat chocolate, grapes, raisins, onions, or garlic. These items are toxic to dogs.
2. I couldn't find your specific topic as a recommended project through this website. That's perfectly ok! If you haven't already, check out these similar experiments. These pages are great resources for what to research, how to set up and control your experiment, data collection, etc.
https://www.sciencebuddies.org/science- ... p028.shtml
https://www.sciencebuddies.org/science- ... p015.shtml


Number of dogs to test:
I know you want to use your pet in the experiment. Do you need to test more than one dog, even of the same breed? To answer this question, think about this: Do you have the same preferences as your friends (even though you are all human beings)? Everyone has different preferences, so testing multiple dogs gives you confidence that the results from your experiment are representative of the entire population of dogs. There are statistical methods to determine how many required, but that is well beyond elementary math. Use at least 3 dogs, and you will be fine. If you use dog breed as a variable, you will need 3 dogs of each breed.

I hope this helps. Good luck, and be sure to write back if you have any further questions!

Thank you for all the information on this topic, we have two dogs but they are not the same breed. The difference between the two is that one lives outside, with the same dog food and no table scraps. The other lives indoor with the same dog food but receives treats and some table scraps. Is it wrong to use both dogs in the experiment even though the breed is different but their diet is entirely different. This is only 3rd grade and my daughter's first big experiment. My husband and I are disagreeing on how scientific to get. Any advice?? We were going to use time of day as the variable a.m. and p.m.

P.S I was very impressed with your answers, we have never used a site like this!

Hello, and thank you for the kind words! Thanks for the reminder that this is an elementary school project. As a statistician, it is very easy for me to forget that it should be kept at the simplest level at this age!

If you haven't already, be sure to check out the resources on this page. It has handouts on judging guidelines at the elementary school level and may guide you more as to what the judges will be looking for. Obviously, don't forget to look on the parents and students tabs as well.
https://www.sciencebuddies.org/science- ... l?From=Tab

At the elementary school level, you want to keep the experiment very simple. Therefore, it's best to only have one variable. In this case, your variable is going to be your treat type (sweet, meat, or vegetable). That means you should keep time of day constant (either morning or afternoon. Do you give the dogs treats at both times? If not, stick with the usual time). Also, I recommend only using one dog. Differences in breed, diet, and lifestyle (indoor v. outdoor) could affect the results if you use both dogs. Which one to use? Sounds like you only give the indoor dog treats(?). That is probably the best. I would include this information in the presentation. Something along the lines of "test was conducted on Breed x, who primarily lives an indoor life and usually receives dog treats." It is important to include this information for those looking at the results, so they understand the boundaries of the test and conclusions.

This can still be a very scientific test (meaning, following the scientific method)....just at the basic level. On the teacher resource page I linked above, there are judging guidelines and handouts. Be sure to check them out. It lists expectations for an elementary school project. In helping your daughter set up and run the test, think about the questions YOU would ask her, and I'm betting it will be similar to what the judges will be asking. Be sure you understand the different steps of the scientific method from the resource pages; and that should trigger questions to ask her to help her prepare for her presentation. Why did you choose this project? How did you set up your test? Which treat did the dog like better?

Since I recommended only using one dog, it is still important to collect more than one data point. Conduct the experiment over several days (3-5 is a good number at her age) and record the results each day. Graphing how many times the dog picked each type of treat is probably doable at her age.

I want to emphasize to be sure to distinguish whether this is testing preference in diet or treats. I recommend treats. To test what is a best diet, that would be a long term project to study the effects on the body from the diet, and it is well beyond elementary school level.

I hope I have answered your questions. Certainly continue to write back if I haven't adequately answered your questions a/o you have more questions as your daughter progresses through the experiment.

Best of luck!

Thank you again for the great answers. Our dog is quickly learning the drill after 2 trials and is quickly proving our Hypothesis wrong, which we didn't want to happen. What is the best way to write a conclusion and end results when our hypothesis is wrong? Should my daughter's grade go down when that happens. I'm not sure how to have her do the conclusion. Any advice is helpful!

There is absolutely nothing wrong with the results being different from your hypothesis, and your daughter should not get a lower score because of that. This is a normal part of the scientific process. If we knew all the answers before we tested, then we wouldn't have to test!

What was her hypothesis going in, and what are the conclusions so far?

In writing her conclusions, she should include the following:
1. What was your hypothesis?
2. Why did you choose this hypothesis? (v. other hypotheses)
3. What is your conclusion?
4. How many trials did you conduct?
5. Why do you think the conclusion is different from your hypothesis?
6. If you ran this test again, since your results are different from your hypothesis, what would you do different?

Here are some additional resources:
https://www.sciencebuddies.org/science- ... ions.shtml

Good luck!