1. Hypothesis

A hypothesis is a proposed explanation that is based on some evidence as a starting point for further investigation.  A hypothesis is important because it guides the research.  You can test it through study and experimentation.  The scientific method is a guide for experimentation and constructing a hypothesis is the third step.

2. Independent Variable 

An independent variable is the variable you have control over.  Changing the independent variable shows the effects it has on the dependent variable, which is then recorded.  There is usually only one independent variable as it makes it easier to know what changes are causing what you observe.

3. Dependent Variable

The dependent variable is ‘dependent’ on the independent variable.  As the experimenter changes the independent variable, the change in the dependent variable is observed and recorded.  When you take data in an experiment, the dependent variable is the one being measured.

4. Control vs Experimental Groups

The difference between experimental groups and control groups is that only one group is exposed to the conditions of the experiment and one is not.  The experimental group is exposed to the independent variable, the changes are observed and recorded.  The control group is separated from the rest of the expirement and the independent variable being tested cannot influence it.

5. Constants

A constant is a variable that scientists want to remain the same.  It is constant and unchanged throughout the experiment.  They are important because you can be for sure about what variable is causing the results.

6. Ways to improve validity and reliability 

Validity measures how correct the results from an expirement are.  It is important because if the results are not valid, then it is meaningless to the study.

Ways to improve:

-Controlling more variables

-Measurement technique

-Randomization to reduce bias

-Adding control or placebo groups

-Blinding the experiment

Reliability is the consistency of results from a measurement tool.  It is important because if a measure is not reliable, we cannot trust what it tells us.

Ways to improve:

-Sample size

-Controlled testing conditions


-Statistical tests

7. Data Collection

Data collection is the process of gathering and measuring information on a specific variable.  This helps you then evaluate outcomes, answer relevant questions and test the hypothesis.  While methods vary by discipline, the emphasis on ensuring accurate and honest collection remains the same.



I hypothesize that the higher protein levels found in wet food make wet food more preferred by cats since they are strict carnivores, they depend on consuming meat to meet their nutritional needs.  Cats prefer wet food to dry food.

The independent variable is the types of cat food- wet and dry.  The dependent variable is the cats preference on which cat food it would rather consume.

The experimental group will give the cats the option between wet food or dry food everyday for a week.  They will record which food each cat picks.  The control group will feed all their cats dry food, so we can compare the two tests.  This will show us whether a cat will pick the wet food over the dry food when given a choice.

The amount of cat food given will be the same for all the cats as well as the quality of the food given, making them the constant.

In the experiment we will be observing whether the cats chose wet food over dry food when given the choice.  The experiment will be tested on 10 different cats that vary in age to reduce bias.  Also will be preforming it for a week straight as repetition will help improve the reliability.

At the end of the week, all 10 cats picked the wet food everyday.  We also then compared the cats who only had dry food and the cats who all chose to have wet food.  The cats who had wet food were more hydrated, had a lower carb intake and consumed the proper amount of protein that they needed.

My hypothesis was proven correct, when given the choice, cats will pick wet food over dry food.  Proving to us that cats prefer wet food to dry food.  Since in my experiment the cats picked wet food 100% of the time.