Reaction Time: The Ruler Drop Test | Science project | (2023)

Science project

Reaction Time: The Ruler Drop Test | Science project | (1)

The nervous system helps information travel through your body. It consists of the 5 senses, your brain, your spinal column, and the nerves that connect them all together. Suppose your eyes see a baseball sailing toward your head. They send a message about the approaching ball to your brain. This message travels to a part of your brain called the cerebrum through nerves. Your cerebrum sends this information to the cerebellum, which has to choose whether to move away, duck, or put a hand up to catch the ball. It finally decides that you should catch it—after all, you’re wearing your baseball glove! The cerebellum sends this decision as message through other nerves to the arm and hand, activating the muscles used to catch the ball.

The time it takes from when your eye first notices the ball to when your arm reaches up to catch it is an example of reaction time. Even though stimuli—or changes in your environment that you react to—travel very quickly along your nervous system as messages, your body doesn’t react instantly. Many athletes spend hours practicing to improve their reaction time. In this activity, you will conduct a simple, measurable experiment (the ruler drop test) to study reaction time and determine how it can be improved with practice.


Fourth Grade




How can reaction time be measured and improved?


  • Metric ruler
  • One or more volunteers
  • Table
  • Chair


  1. Ask your first volunteer to sit in the chair with good upright posture and eyes looking across the room.
  2. Have the volunteer place her forearm (the part of the arm from elbow to hand) so it extends over the edge of the table.
  3. Ask the volunteer to place her thumb and index (pointer) finger on either side of the bottom of the vertically placed ruler. The number “1” should be on the bottom, the “30” near the top.
  4. Let your volunteer practice holding the ruler with those two fingers.
  5. Now, ask your volunteer to remove her fingers from the ruler while you continue hold it so that the bottom of the ruler is at a height of 2cm above her fingers.
  6. Tell your volunteer that you will release the ruler without telling her. Her job will be to catch it with her thumb and forefinger as soon as she senses it dropping.
  7. Drop the ruler. When your volunteer catches it, record the number on the ruler displayed just over her thumb. The lower the number, the faster her reaction time.
  8. Conduct several trials with the same volunteer, dropping the ruler from 2cm above her fingers each time.
  9. Make sure to record the results for each trial in a table similar to the following:


cm trial 1

cm trial 2

cm trial 3

cm trial 4



  1. You might consider letting your volunteers have a rest between trials.
  2. Repeat the experiment with at least one other volunteer.


Your results will vary depending on technique and which volunteers you used, but you should expect that many of your volunteers will show a slight improvement with practice.


When we begin to acquire a new physical skill through repetition, our nervous system creates new neural pathways. Here’s an example: when we practice something like catching a ruler over and over again, all the members of that neural pathway (eye, brain, muscles) become more well-connected and efficient. This phenomenon is often referred to as muscle memory. However, no matter how good your muscle memory for this task becomes, it will always take some time for the falling ruler to travel as a message from your eyes to your brain and from your brain to your fingers!

Going Further

Reflexes in response to stimuli are our quickest reactions. One example is when a doctor hits a spot right below your kneecap and you kick before you even consciously realize you’re doing so. One cool question to explore might be whether reflexes and learned motor skills like catching a ruler can enable us to respond to stimuli more quickly in the morning or in the evening. How does the length of time spent awake affect the efficiency of our central nervous system? Why?

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(Video) Reaction Time: The Ruler Drop Test Experiment (muscle memory / science project)

Warning is hereby given that not all Project Ideas are appropriate for allindividuals or in all circumstances. Implementation of any Science Project Ideashould be undertaken only in appropriate settings and with appropriate parentalor other supervision. Reading and following the safety precautions of allmaterials used in a project is the sole responsibility of each individual. Forfurther information, consult your state's handbook of Science Safety.

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(Video) GCSE Science Revision Biology "Required Practical 7: Reaction Time"


How does the ruler drop test measure reaction time? ›

The time between noticing something (the ruler falling) and then responding to it (catching the ruler) is known as reaction time. We use our eyes and other sensory organs to detect what's going on around us. Understanding this information and deciding how to respond to it is the job of the nervous system.

What is a good score on the ruler drop test? ›

ExcellentAbove AverageAverage
<7.5cm7.5 - 15.9cm15.9 - 20.4cm
Jul 10, 2022

Is the dropping a ruler experiment a reliable measure of reaction time? ›

The ruler-drop test has acceptable test-retest reliability that compares favorably with computerized measures of reaction time.

How do you test reaction time in an experiment? ›

Ask a friend to put their thumb and index finger slightly open at the bottom of the ruler, with the ruler between their fingers. Drop the ruler and record the measurement on the ruler where the other persons fingers are. Repeat for all participants. Let each person have three attempts and record the average value.

How do you read a ruler test? ›

The longer the line on the surface of the ruler, the bigger the measurement is. Ranging from 1 inch to 1/16 of an inch, the lines decrease in size as the unit of measurement does. Make sure you read the ruler from left to right. If you are measuring something, align it with the left side of the zero mark on the ruler.

What does the drop test measure? ›

The drop test method has been used successfully to measure the interface energy between particles and a surface based on a balance between adhesive and tensile forces.

What affects reaction time? ›

Many factors have been shown to affect reaction time including gender, age, physical fitness, level of fatigue, distraction, alcohol, personality type, limb used for test, biological rhythm, and health and whether the stimulus is auditory or visual [5]. Reaction time is independent of social-cultural influences.

What is the answer of reaction time? ›

Reaction time or response time refers to the amount of time that takes places between when we perceive something to when we respond to it. It is the ability to detect, process, and respond to a stimulus.

How can I improve my ruler drop test? ›

Drop the ruler. When your volunteer catches it, record the number on the ruler displayed just over her thumb. The lower the number, the faster her reaction time. Conduct several trials with the same volunteer, dropping the ruler from 2cm above her fingers each time.

Is 0.72 seconds a good reaction time? ›

Is 0.72 a good reaction time? The average reaction time is between 0.2 and 0.3 seconds. Anything under 0.2 is excellent. Above 0.3 is slow.

How does reaction time affect accuracy? ›

Reaction time and accuracy are often assumed to measure the same things, with reaction time being a finer-grained measure than accuracy. This study argues that they measure different processes and often produce slightly different results. This experiment is counterbalanced by Subject.

Does age affect reaction time? ›

Adult human reaction times in response to simple tasks slow with age at a rate of 2–6 ms per decade (1–3).

Does reaction time impact accuracy or precision? ›

... that correct trials have longer reaction times than errors, the probability of being correct must increase with reaction time. On further analysis, we found that accuracy increased with reaction time from about 500-1200 ms, as shown for one experiment in Figure 2a.

What is good reaction time? ›

The average reaction time to visual stimulus is around 250 milliseconds, and most people seem to be hard capped at around 190-200 ms with training.

What is the average reaction time for a 14 year old? ›

Average reaction time, by age and dominant hand
Age (years)Right-handedLeft-handed
13 more rows

What is the best reaction time? ›

The fastest possible conscious human reactions are around 0.15 s, but most are around 0.2 s. Unconscious, or reflex, actions are much faster, around 0.08 s because the signal doesn't have to go via the brain.

What is reaction time with Example? ›

Reaction time is a simple form of speed, and depends mainly on the nervous system. It is the time interval between a signal and the reaction to it—for instance, when the starter pistol is fired at the start of the 100 m.

What 4 things can affect reaction time? ›

Many factors have been shown to affect reaction times, including age, gender, physical fitness, fatigue, distraction, alcohol, personality type, and whether the stimulus is auditory or visual.

What's an example of reaction time? ›

Simple reaction time examples include things like starting a sprint in response to the starting pistol. The sound of the gun is the stimulus, and starting the race is the response. The time between the gunshot sound reaching your ears and you taking the first leap of the race is the reaction time.

What are the 16 marks on a ruler? ›

A ruler marked in 16ths. Every mark is 1/16th of an inch. The center mark between numbers is 1/2.

What type of test is a drop test? ›

A drop test is a test designed to examine the structural integrity of a product. Drop tests usually involve an object being dropped from a predefined height onto a second object or surface. The object being tested can be either the dropped object or the object/surface that an object is being dropped on to.

How do you calculate reaction time from distance? ›

We can use the distance the meter stick fell before you caught it to figure out your reaction time. The following formula is the basis: d = 1/2 gt2. In this formula, “d” equals the distance the object fell, “g” equals gravitational acceleration (9.8 m/s2), and “t” is the time the object was falling.

What causes reaction time difference? ›

Factors that can affect the average human RT include age, sex, left or right hand, central versus peripheral vision, practice, fatigue, fasting, breathing cycle, personality types, exercise, and intelligence of the subject.

Does sleep affect reaction time? ›

Reaction times increase as a person accumulates sleep debt6. This means that the more sleep a person loses, the longer it takes for them to react to a stimulus. In one study, research subjects were allowed to sleep for five hours per night for a week.

Can you increase reaction time? ›

Unlike reflexes, which aren't processed by the brain, reaction time can be strengthened and improved through lifestyle changes. Cognitive exercises, meditation and mindfulness, and nutritional supplements are all factors that can boost reaction time in a safe and healthy way.

What are 10 reaction examples? ›

Types of Chemical Reactions
  • Decomposition reaction.
  • Combination reaction.
  • Combustion reaction.
  • Neutralization reaction.
  • Single displacement reaction.
  • Double displacement reaction.
  • Precipitation reaction.
  • Redox reaction.

What are the 4 types of reactions? ›

Types of Chemical Reactions
  • Synthesis reactions.
  • Decomposition reactions.
  • Single-replacement reactions.
  • Double-replacement reactions.
Feb 19, 2020

What are 5 exercises for reaction time? ›

This sort of program helps athletes quickly perform sport-specific tasks during competition.
  • Reactive Gear Drill. Level 3. ...
  • Reactive Sprint and Backpedal Drill. Level 3. ...
  • Wave Drill. Level 3. ...
  • Shuffle Reaction Ball Drill. Level 3. ...
  • Ball Drops Drill. Level 3.

Does height affect reaction time? ›

Height was one trait they examined. Since the foundation of reaction time is neurological, it stands to reason that a taller athlete might have slower reaction times because signals have further to travel down the nerves.

Why does reaction time improve with practice? ›

The real key to reaction time is practice. By repeating the same movements, you make them almost automatic.

Can a human react in 0.1 seconds? ›

In humans, reaction time usually varies between 0.3 and 0.1 seconds, though the average tends to lie between 0.25 and 0.2 seconds.

Is 0.5 seconds a good reaction time? ›

The average motorist is much slower to react: around 0.5 of a second is still good, 0.8 of a second is satisfactory and even one second is not too bad. Anything longer than a second is beginning to be dangerously slow.

Is 0.4 reaction time slow? ›

The average reaction time is between 0.2 and 0.3 seconds. Anything under 0.2 is excellent. Above 0.3 is slow.

Does reaction time depend on speed? ›

Reaction time depends to some extent on the distance to the obstacle and whether it is approaching from the side and is first seen in peripheral vision. The best estimate is 1.5 seconds for side incursions and perhaps a few tenths of a second faster for straight-ahead obstacles.

Is reaction time affected by speed? ›

The reaction distance increases linearly as a function of speed, whereas the braking distance increases more or less quadratically as a function of speed. The braking distance will therefore be nearly 2.5 times as large at 110 km/h compared with 70 km/h.

What happens if your reaction time is slow? ›

“Reaction time may indicate how well our central nervous and other systems in the body are working. People who are consistently slow to respond to new information may go on to experience problems that increase their risk of early death. In the future, we may be able to use reaction times to monitor health and survival.

What causes loss of reflexes? ›

Usually, absent reflexes are caused by an issue with the nerves in the tendon and muscle. You may have other muscle symptoms along with areflexia, like weakness, twitching, or atrophy.

Why do females have a slower reaction time? ›

An average male has twice the amount of upper body strenght compared to a female. That says enough. Physically men are stronger than females, faster and quicker.

Is reaction time an error? ›

Reaction time – If your experiment involves timing with a stopwatch for example, the speed at which you stop the timing may affect how close to the true value the experimental measurement is. As you may have different reaction times with each round of the experiment, this is a random error.

Is reaction time a source of error? ›

One source of error is our reaction time. This is a random error: we may delay too long in starting the watch, or delay too long in stopping the watch. In practice, the reaction times will not be the same in repeated measurements; our measured times will be randomly distributed around the true time.

Does IQ affect reaction time? ›

Reaction time is moderately related to IQ, but is a simpler assessment of the brain's information-processing ability - one that doesn't bear so much on other, possibly confounding factors like knowledge, education, or background.

Why is the distance the ruler fell considered as the reaction time? ›

This information travels from sensory neurons along the optic nerve from the eye to the brain. The brain processes this information, then sends a signal through motor neurons down the arm to tell the muscles in the hand to close and catch the ruler. The amount of time this all takes is what makes up our reaction time.

How is drop test measured? ›

Safeopedia Explains Drop Test

If the surface being dropped onto is what's being tested, its ability to withstand a specific amount of impact force is measured by dropping a standardized amount of weight and mass (often a sandbag) onto it from a defined height.

Is reaction time always the same? ›

In this example, the processes (perceive, process, and respond), are done in a matter of milliseconds, but reaction time can vary depending on a variety of factors: Complexity of the stimulus-The more complex the stimulus, the more information that has to be processed, the longer this process will take.

What is the use of drop test? ›

Drop tests may be used to verify the aerodynamic performance and flight dynamics of the test vehicle, to test its landing systems, or to evaluate survivability of a planned or crash landing.


1. Reaction Time | Ruler Drop Test | Performance Task in Physical Education for Grade 5
(Team Martinez)
2. How to measure your reaction time
(Robert Hildebrand)
3. Algebra - Ch. 26: Solving Problems with Quadratic Equations (11 of 11) What is Your Reaction Time?
(Michel van Biezen)
4. GCSE PE - Components of Fitness (Testing) / Reaction Time - Ruler Drop Test (Scarborough College)
(Brett Cunningham)
5. 18.05.20 - Science Project: The Ruler Drop Reaction Test!
(Sophie Le Marchand)
6. Measurement at Home Challenge: Reaction Time
(National Physical Laboratory)
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