Using only these supplies, which question can Brandon investigate with an experiment?
Are dishes washed in a dishwasher cleaner than dishes washed by hand? Are dishes cleaner when washed with a soapy sponge or with a soapy rag? Are dishes cleaner when washed with liquid dish detergent or with bar soap?
Brandon is washing dishes after cooking his dinner. He notices that some of the dishes still feel oily after being washed. He wonders what factors affect how clean dishes are after they are washed. So, he decides to design an experiment. He has the following supplies available:
a sponge
liquid dish detergent
a bar of soap
hot water
cold water
a pile of dirty dishes
Experiments can be designed to answer specific questions. When designing an experiment, you must identify the supplies that are necessary to answer your question. In order to do this, you need to figure out what will be tested and what will be measured during the experiment.
Imagine that you are wondering if plants grow to different heights when planted in different types of soil. How might you decide what supplies are necessary to conduct this experiment?
First, you need to identify the part of the experiment that will be tested, which is the independent variable. This is usually the part of the experiment that is different or changed. In this case, you would like to know how plants grow in different types of soil. So, you must have different types of soil available.
Next, you need to identify the part of the experiment that will be measured or observed, which is the dependent variable. In this experiment, you would like to know if some plants grow taller than others. So, you must be able to compare the plants' heights. To do this, you can observe which plants are taller by looking at them, or you can measure their exact heights with a meterstick.
So, if you have different types of soil and can observe or measure the heights of your plants, then you have the supplies you need to investigate your question with an experiment!