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Science Fair: Crystal Fudge
Transcript of Science Fair: Crystal Fudge
1. Why do some rocks that are made of the same minerals have crystals that are different sizes inside them?
2. What effect will faster verses slower cooling time have on the formation of crystals?
1. In my opinion, I think that rocks that are made of the same minerals have a difference in the size of their crystals because some rocks are older than others. I think that the rocks that have been around longer will have bigger crystals because they had more time to form.
2. I think that the fudge with the longer (slower) cooling time will have bigger crystals because the fudge will be out longer and I think this will allow it to have bigger crystals
List of Materials:
• Two bread pans (8”)
• Butter or wax paper (to coat pans)
• Large saucepan
• Wooden spoon
• Candy thermometer
• 3oz. unsweetened chocolate
• 3 cups of sugar
• 1 cup of warm half-and-half or evaporated whole milk
• 1 teaspoon of corn syrup
• ¼ teaspoon of salt
• 3 teaspoons of butter
• 2 teaspoons of vanilla extract
1. Butter the pans or line them with the waxed paper.
2. Mix the chocolate, sugar, salt, half-and-half, and corn syrup over medium-low heat. Keep stirring until the chocolate is melted and the fudge begins to boil.
3. When the fudge begins to boil, stop stirring and put the candy thermometer in. Clip it to the edge of the pot, making sure the tip isn’t touching the bottom.
4. Let the fudge cook without any stirring until it reaches the soft-ball stage.
5. Take the fudge off of the burner and let it cool, undisturbed, until it’s 150 degress.
6. Add the vanilla and butter and keep stirring until the surface of the fudge starts to get dull. This can take a long time, but you need to keep stirring! Maybe you can get a partner to help.
7. Spoon half of the fudge into each pan. Put one pan in the refrigerator and leave the other one out at room temperature. Allow both of them to cool completely.
Summary of Results
The fudge that had the slower cooling time had bigger crystals than the fudge that had the faster cooling time. Therefore, my hypothesis’ were right.
In conclusion the fudge with the bigger crystals was the fudge that had the slower cooking time. In my hypothesis I thought this would happen because the rocks had more time to form. This is like a plutonic igneous rock (is formed through the cooling and solidification of magma or lava) that has cooled and solidified slowly, under the surface, like granite. The fudge that had the bigger crystals was a lot grainier than the fudge with the faster cooling time. The reason why I thought the fudge with the faster cooling time would have smaller crystals is because it didn’t have as much time to form its crystals. This is like a volcanic igneous rock (a rock formed from magma erupted from a volcano) that cooled quickly above the earth’s surface, like obsidian (a hard, dark, glass like volcanic rock formed by the rapid solidification of lava without crystallization). When magma cools, crystals form because the solution is super saturated (a state of a solution that contains more of the dissolved material than could be dissolved by the solvent under normal circumstances). If magma, or in this case fudge cools quickly, the crystals don’t have a lot of time to form so they are small. If magma (fudge) has a lot of time to cool the crystals have lots of time to grow and they become large.