Biology

8th grade science fair projects are especially fun when you can use human subjects. Here you’ll find two projects that test peoples’ responses to sense-stimuli.

How do people know what flavor they are tasting? Is it just their tongues that tell them, or are their eyes involved as well?

These classic 8th grade science fair projects use the “blind taste test” method to determine whether the color of a liquid influences people’s ideas about what flavor it is.

Project #1:
Taste and Suggestion




MATERIALS:

  • 5 flavored waters (simple one-fruit flavors work best, rather than blends)
  • 5 food colorings
  • At least 15-20 kids to participate

INSTRUCTIONS:

1. Come up with your hypothesis – do you think that people’s visual expectation of what flavor they are drinking affects what they actually taste.

2. Prepare your samples by adding color to each of the 5 flavored waters. Make sure the color DOES NOT match the flavor, i.e. a lemon-flavored drink could be colored red, a cherry-flavored drink could be colored green.

3. Gather a list of your participants. Split the list in half and label one “control group” and one “test group”

4. For every participant on the “control group” list, don’t let them see the drink. Blindfold them while they do the test and/or serve it in an opaque bottle so that they cannot see what color is. Ask them what flavor they detect and write down their response.

5. For every participant in the “test group,” put the drink in a clear plastic cup before giving it to them, so that they clearly see its color. Ask them what flavor they detect and write down their response.

6. Do the responses of the two groups match? If not, where do they diverge? Was your hypothesis confirmed?

*TIP: Complete your 8th grade science fair projects by adding a “no humans were harmed during the making of this project” sticker in the corner of your poster

 

 

Project #2:
Does Age Affect Reaction Time?




Human reaction time refers to the time it takes between when we perceive something and when our muscles can respond to it. It is a crucial ability for all animals: think about the time it takes to perceive a potential danger, react to it, and avoid it before you are hurt. These 8th grade science fair projects will investigate whether older or younger people have faster reaction times, or whether they are all the same.

MATERIALS:

  • Ruler
  • At least 20 participants of various ages – the more the better!

INSTRUCTIONS:

1. Come up with your hypothesis – do you think older or younger people will react more quickly to stimuli? By a lot, or just a little?

2. Write down the name and age of each participant on a data sheet.

3. For each participant, hold the ruler by the top end (the one with “12 inches” or “30 centimeters,” etc.), with the “0” end in between the thumb and forefinger of your participant

4. Have the participant open their thumb and forefinger, ready to grab the ruler as soon as it falls

5. Wait a few seconds, then drop the ruler. Write down how many inches or centimeters the ruler fell before they managed to grab it.

6. Repeat with each participant at least 10 times, then calculate the average

7. Repeat for all of your participants

8. Plot the results on a graph with age on the x-axis (horizontal) and response time on the y-axis (vertical)

9. Does the resulting graph have a general trend up or down? Or are the data points scattered randomly? Does this match your hypothesis?

*TIP: Can you come up with a way to calculate the response time as a measure of time rather than one of distance? In other words, can you convert your inches and centimeters into seconds? This will make your 8th grade science fair projects especially scientific.

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