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Science Rocks!

Reaction Time


your results

Sent in by:
Kelsey of Incline Village, NV

Take action to time your reaction!

Materials Needed

  • ruler with centimeter marks
  • table
  • paper and pen for charting results
  • a different colored sticker or pen for each person



  1. Has anyone ever said, "Think fast!" and then thrown something at you? How quickly or slowly you react is called your reaction time.
  2. To measure your reaction time, ask a friend to help.
  3. You will need the reaction time chart below.
  4. Then draw a graph to record your results. Along the left side of the paper (the y axis) write the times from the reaction time chart in separate rows. Across the bottom of the paper (the x axis) write "Trial 1", "Trial 2", and "Trial 3" in three separate columns. You will record each other's reaction times on this graph to compare them when you finish testing.
  5. Now, sit in a chair with your arm resting on a table so that your wrist hangs off the edge.
  6. Your friend will hold the ruler so that it dangles above your hand. Make sure the end of the ruler is hanging between your thumb and finger.
  7. When your friend lets go of the ruler, try to catch it between your thumb and finger as quickly as you can.
  8. Compare the marking on the ruler where your fingers caught it to the reaction time chart. Your reaction time is how long it took for your eyes to tell your brain that the ruler was falling and then for your brain to tell your fingers to catch it.
  9. Make a mark on your graph next to the matching reaction time over the Trial 1 column.
  10. Try catching the ruler twice more, marking the results on your graph each time. Give your friend (or friends) a chance to test their reaction times.

Who has the best reaction time? Do your reaction times improve with practice? Did your reaction times vary a lot or were they pretty much the same from trial to trial? Are older kids faster than younger kids? How about your parents? Come up with your own questions. Then test them out, and send your results to ZOOM.

Some of your Results

Joey, age 12 of Eagle, OR wrote:
i got. 10

Dianne, age 12 of Nashville, TN wrote:
When I did it my reaction time with my right hand it was 0.18. But with my left hand I got 0.24.

Briana, age 15 of Centreville, VA wrote:
I tried it five times and my reaction time was under. 10 seconds every time. But how far above your hand should your friend hold the ruler?

Devyn, age 9 of Sunrise, FL wrote:
My time average time was the same as my mom's! I thought older people would be faster than younger people.

Jesabel, age 16 of Honolulu wrote:
Well it went well UNTIL... we tried to convert 1centi, 8centi, 9centi aka the ones not on the chart. You should have on the chart 1centi through 30 centi. Thanks to Matthew we got our equation. Also your show should still be on air.

Mathew of Milwaukee, WI wrote:
I did this experiment for my physics class. I use the equation t = sqrt (2y)/g) to get the reaction time. Convert centimeters to meters then put it in for y and g is gravity at 9. 8!

Claire of San Francisco, CA wrote:
I got it at 1 cm!

Awet, age 16 of Randallstown, MD wrote:
caught it at 2 centimeters

Robert, age 12 of Tamarac, FL wrote:
when I did it my dad had the fastest reaction time I thought I would.

ZOOM Fans, age 10 of TN wrote:
It's a group of 5. The oldest did the best. We did better than our first try on our 2nd and 3rd try. The youngest did last but he did good. Our results were good but the experiment was confusing. The average was 0-11. We had a lot of fun doing this experiment.

Noah, age 11 wrote:
Im doing something related to this and so far the adults have done worse

Noah of Murfreesboro, TN wrote:
mine stopped at 16 cm. faster than all of my partners.

Chase, Spencer, Sadie, Josh of TN wrote:
The first persons best was 4cm 2nd 11 cm 3rd 6cm 4th 23 5th 11

Kayley, age 9 of Murfreesboro, TN wrote:
I got two 16's and one 11

Ashley, age 12 of Pittsburgh, PA wrote:
Older people are faster than younger people are. I thought that younger people are faster than older boy was I wrong.

Lidiette, age 13 of Bethlehem, PA wrote:
the first time I tried it I caught it at 17cm. im not so good at it. My older brother and sister caught it the fastest...(maybe because they are athletes)

Helena, age 16 of Memphis, TN wrote:
I did this experiment for a science project at school and I got 28 cm! I'm really bad at it! I found that the boys were faster than girls and that younger people were faster than older people.

Catherine, age 11 of Gulfport, MS wrote:
I caught it at. 5cm! That is awsome!!

Yann, age 12 of Miami, FL wrote:

Julia, age 13 of Austin, TX wrote:
Boys have faster RT than girls your reaction time improuvs as you get older

Dasha, age 12 of Atlanta, GA wrote:

Cathleen, age 10 of Dearborn, MI wrote:
i caught it at 2 cm!!!

Brianna, age 11 of Woodstock, GA wrote:
I got it a 4 cm!!! It was fun!!!

Fantasia, age 15 of Paterson, NJ wrote:
It was so cool!! I tried it and it was really fast. But I caught it at 2cm 1in. It was fun.

Matthew, age 12 of Quincy, MA wrote:
I was the fastest in my family!

Dana, age 12 of Winnipeg, MB wrote:
I caught the ruler at 5cm.

Amrinder, age 13 of Vancouver, BC wrote:
When I did this I caught the ruler at 2cm and 3seconds.

Grace, age 11 of Albert Lea, MN wrote:
Well I did it for a science project and im not quite finished with it but I know boys have a faster reaction time.

Grace of MN wrote:
I did it for a science project and boys do have faster reaction times than girls.

Treasure, age 12 of Memphis, TN wrote:
When I did it I missed it the first time then the second time I caught it at 5 1/2 centimeters.

Amber, age 13 of Kingston wrote:
Everyone that we read out had slow reaction times compared to our class, which was 19 seconds on average.

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