Reaction Time

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Students will be able to measure and graph their reaction time using metric measurements.

Big Idea

CCSS Measurement and Data: Represent and interpret data

Engaging Students

30 minutes

This is a lesson where students get excited about measuring to the nearest quarter inch.  Before I start this lesson I have my students brainstorm what our classroom will look like, sound like and feel like during this activity.  The purpose of this is to help students to develop their own internal monitoring of their behavior, rather than relying on me to remind them. Yes, I will have to remind them, but I believe it is important that I also help them to develop this self awareness. 

It looks like all students are working, sounds louder than normal but not loud enough you can’t hear your partner and it feels like fun and a lot of learning. 

Review with your students, if you need to, how to measure to ¼ of an inch, before beginning the lesson.

In this lesson, students will be dropping a ruler into their partners hand and the partner will catch the ruler.   (You can see my students doing the experiment in this video.)  Where their index finger or thumb end up is how far the ruler fell or the measurement they are writing down.  Have your students record ten drops for each partner. 

You can see some student work here. 



Gathering Data

15 minutes

While your students are doing the activity and you are circulating, also draw a number line on the board showing the span 0 to 12.  Ask your students why you would start at 0 and end at 12.   I ended the number line at 12 and then we problem solved for the students who did not catch the ruler – they were 12+ so we added a place for 12+ on the number line.  

I include marks for the ¼, 1/2 and ¾ places but did not write them in.  This was a student request because they had to copy the number line and they agreed they all understood where the places should be on the line.  I have two students, who completed their, work finish the number line for me while I walk around checking in with students.  As students finish their measurements they come to the board (I have a rule of no more than three at a time) to include their data on the line plot graph (number line). 

Reaction Time Data Collection Student Video


Analyzing the Data

10 minutes

To finish the lesson, I ask my students, “What does the graph tell you about reaction times?”  They all agreed the most often occurring reaction time was zero and the next often was six. 

Here is an example of the finished line plot

One student commented that it was possible that everyone recorded a zero because there were more marks over the zero than numbers of students in the class – he was giving evidence for the reasonableness of his answer (MP2, MP3).  Another student comments that almost all places on the number line have an X above it, and then went on to note which ones did not have any marks.  Doing a line plot for data analysis really gives my students a visual representation of reaction times. 

Reaction Time Data Analysis video of student discourse (MP3)