Ella's Experiment

Ella's Experiment

Formulating A Hypothesis: You Know More Than You Think!

Experimental Design: Beyond Variables

Inquiry Progressions: How Do You Say Water...

What are your questions? Review Question Set #1:

What is evaporation?
How does it occur?
What factors (variables) influence or can affect the rate of evaporation?
Do all liquids evaporate?
Do all liquids evaporate at the same rate?
What other liquids could Ella test in this experiment?

As you may have noted, many of these questions have a direct bearing on Ella's experimental design and will be elaborated in the next section. For now, let's consider Ella's hypothesis and your own hypothesis. A hypothesis is an educated guess, formed and based on your experience and knowledge, and your ability to apply your reasoning skills to that information. What might six-year old Ella's experiences be with evaporation? In other words, how has she experienced evaporation, and how might her experiences differ from yours?

Which of the following experiences apply to you...1) have you observed a puddle of water disappear after several days; 2) have you worked on an art project and left it to dry for an hour or two; 3) do you routinely water your plants; 4) have you cooked vegetables or soup and left it on the stove too long; or, 5) have you ever felt chilled or just a bit if cooling relief after sweating? These are all encounters most of us have had with the natural phenomenon known as evaporation.

Are there any conclusions or generalizations you can draw about evaporation based on these experiences? Evaporation happens; the rate of evaporation seems to be affected by heat/temperature; and, most of our previous encounters with evaporation involve water. Since our goal is to determine whether water, apple juice or oil will evaporate first, it would seem prudent to also ask a few questions about the liquids Ella plans to include in her experiment.

	What do water, apple juice and oil all have in common?	They are all liquids.
	Can the three liquids be grouped or classified based on their properties?	Water and apple juice are more similar to one another than either is to oil.
	What is apple juice?	Read the ingredients on a bottle of apple juice. In addition to a variety of additives, the primary ingredients in apple juice are water and the juice from apples, i.e. sugar and water.
	What do you know about water, apple juice and oil that is related to evaporation?	We know water evaporates. We know that apple juice has water in it and will likely evaporate as well. But what about that oil? Does oil evaporate?

Ella has her hypothesis. She thinks apple juice will evaporate first.
What is your hypothesis? Which do you think will evaporate first?

Experimental Design: Beyond Variables

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