VanCleave's Science Fun

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With mouth wide open, vibrating air coming up the throat from the vocal chords leaving the open mouth and spreading in all directions. Hi, I am Janice VanCleave, author of 50+ best-selling science experiment books for children ages 4 through high school. I taught science for 27 years and now am creating this science website.   My scream was not staged. The picture was to be of two adult cats, which I was holding. A microsecond before the camera snapped, the two cats dug their claws into my skin as they prepared to leap out of my arms. A picture like this is great for making inferences. Kids could make "guesses" as to why I am screaming. They would be drawing on facts from the photo, such as I look like I am in pain or maybe I am just pretending.

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Home » Crystal Project: Variables

Crystal Project: Variables

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halite1A variable is something that can change. For your science fair project, you should change one variable to see what affect it has on another variable. These two variables are:

independent variable: Something that you choose to change.

dependent variable: Something that changes in response to changes in the independent variable.

1. Following are ideas for listing the possible variables for the exploratory experiment   HALITE CRYSTALS.

Notice that I am listing for each step possible changes to the experiment.

Step 1: amount of water, type of water

Step 2: amount of salt added, type of salt added

Step 3: type of surface the solution is poured onto

Step 4: where the tray is placed, the temperature of where the tray is placed

2. The purpose for the exploratory experiment is to describe the physical properties of halite crystals that form by evaporation.

Select one procedure step for the exploratory experiment at a time and ask yourself questions, such as these:

Step 1: Would changing the amount of water affect the physical properties of the halite crystals?

Would changing the type of water affect the the physical properties of the halite crystals?

Step 2: Would changing the amount of salt affect the the physical properties of the halite crystals?

Would changing the type of dissolved salt affect the the physical properties of the crystals that form?

Step 3: Would changing the surface the crystals are grown on affect the the physical properties of the halite crystals?

Step 4: Would changing where the tray is placed affect the physical properties of the halite crystals?

Would changing the temperature of where the tray is placed the physical properties of the halite crystals?

3. Pick one of the questions from step 2 that most interests you.

My choice is: Step 2:
Would changing the type of dissolved salt effect the physical property of the crystals that form?

or

Would changing the type of dissolved salt effect the physical properties of evaporite crystals that form?

Notice that the chosen question has an independent variable (type of salt) and a dependent variable (physical properties of crystals).

I can use the question as stated, but questions that can be answered with a yes or no are not preferred by some teachers.

4. Writing A Project Question

I only need to make a small change in the question in step 3.

How does the type of dissolved salt effect the physical properties of evaporite crystals?