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Design an experiment to test UV

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Presentation on theme: "Design an experiment to test UV"— Presentation transcript:

1 Design an experiment to test UV

2 How can you protect yourself from UV radiation?
What are some things you might use to protect yourself from UV? Sunscreen Sunglasses Hat Clothing Shade

3 How will you know if you have been exposed to UV?
We can’t see UV with our eyes so we will need a sensor to monitor it We have plastic beads that change color with exposure to UV

4 Design Experiment Step 1
Select an independent variable to test: something that will block the UV Materials we have: 4, 15 and 45 SPF sunscreen (apply to clear plastic) White T-shirt material Aluminum foil, Plastic wrap, white paper Your own hat, sunglasses, hair, shirt, jacket etc.

5 Design Experiment Step 2
Identify your dependent variable: How will you know if the UV exposure changed because of your choice of independent variable to block the UV? The color change in the beads – how long it takes and how dark it becomes (put on scale of 0 no change to 5 darkest

6 Design Experiment Step 3
Create a control group so you know what would have happened to the bead color without your independent variable blocking the UV. Control groups give you a basis for comparison. UV beads exposed to the sunlight without anything to cover them – how long does it take them to get dark? Test your control group first so you know what to look for with your experimental group

7 Constants (Controlled Variables)
Things that you keep the same between your groups to make it a fair test. What things will affect the changing color of the beads? Exposure to UV light

8 How can you control the exposure to UV light?
Cover the beads until you are ready to test them (aluminum foil covered petri dishes) Watch out for shadows Same angle towards the sun Cover beads with your independent variable as soon as you remove the cover on the petri dish Same amount of time exposed before rating darkness of bead

9 Write Up In Notebook Title – must include independent and dependent variable Independent Variable Dependent Variable Hypothesis Control group Constants/Controlled variables Data table Graph of numeric data (time or darkness rating) Conclusion

10 Data Table Need a column for Independent variable Need a column for Dependent variable Row for each trial you conduct

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