Integrated Science Day 8

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Integrated Science Day 8

• September 24, 2012

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Learning targets

1. I can evaluate a laboratory procedure and analyze
   the data to form a conclusion
2. I can Set up an Inquiry lab by coming up with an
   investigative question and determining my needs
   for the lab.

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Agenda

• Kick off question
• What ideas do you have for your science fair
  project?
• Heart rate lab conclusion should be turned in for
  a grade
• Daphnia Lab conclusion turned in today
• Set up for the effect of substances on organisms
  in our waterways
• Learning log What is a bioassay?

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Water Contamination

• How do we know what is clean water? In other
  words, how do we know if water is safe for
  humans and wildlife?

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Bioassays- notes

• Dose/Response Bioassays are used to
• Estimate toxicity to humans.
• Estimate maximum concentrations of specific
  chemicals allowed to discharge into bodies of
  water.
• Investigate hazardous waste sites.

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Bioassay

• A bioassay involves the use of biological
  organism to test for chemical toxicity.

Canaries are used by coal miners as a way to test
for high levels of methane (an odorless gas)
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Bioassay Species

• 3 organisms are often used
• Daphnia
• Duckweed
• Lettuce Seeds
• Expose organisms to chemicals and measure how
  they respond.

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Used by the FDA

• Bioassays are used to test drugs and skin care
  products before being okayed by the FDA.

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Daphnia
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CONCENTRATION VS. DOSE

• LD50 the Dose that is Lethal for 50 of the test
  organisms.
• Used for Daphnia
• TC50 the Concentration that causes a 50 drop in
  growth or health of the test organisms (Toxic
  Concentration).
• Used for seeds (they may not die, just not
  sprout)

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An Introduction To Experimental Design

• The Treatments in an experiment represent the
  factor that you vary while keeping everything
  else constant.

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An Introduction To Experimental Design

• The control is the untreated group, used for
  comparison with the treatment groups.

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An Introduction To Experimental Design

• Replicates are groups of organisms exposed to
  identical conditions.
• The more replicates the better.