Course overview

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 License. Quick teaching topic: communication speedThis three slide presentation uses two communication timing examples round trip time for an Internet packet from Los Angeles to southern Chile and the time it takes to see and pick up a pen. (Which do you think is greater)?

I use it to introduce Ping, define a millisecond and emphasize the dramatic speed of Internet communication and our knowledge of the brain and nervous system. I intend it to generate interest in subsequent modules on data communication rate. 1Where does this topic fit?Internet conceptsApplicationsTechnologyImplicationsInternet skillsApplication developmentContent creationUser skills2

Sending an Internet packet from Los Angles to Punta Arenas, Chile and backSeeing a pen and picking it upEstimate the time you think each of these would take.Communication speed -- which takes longer?

It turns out they both take about second.

Lets see how I came to that conclusion, starting with seeing and picking up a pen.3

The time to see and pick up a penExcerpt (1m 55s) from a Radiolab program on Speed

Radiolab, my favorite science podcast, produced a program on speed.

They talked about several examples, including the speed with which telegraph messages travelled, the time it takes a computer to send a trade message on the New York Stock exchange and stopping light in the lab.

This excerpt enumerates the time spent traversing communication links between your eye and brain, between different regions of your brain, and from your brain to your muscles.

Listen to the excerpt and you will learn that each step takes a little time, and adding them all up, we get to about second.

Our focus here is on communication speed, but one cannot help being impressed by the speakers precise knowledge of brain function and speed.

4

Ping time: Los Angeles to Punta Arenas, ChileThe average packet round trip is 259 milliseconds what is a millisecond?

What do the Internet routers and neurons in your brain have in common?

Ping is an application that measures the time it takes a packet to go from an Internet client to a server and receive an acknowledgement packet back from the server.

In other words, it measures the time for a round trip between two points.

In this example, Ping sent four test packets from my laptop in Los Angeles to a server at the Universidad De Magallanes, in Punta Arena, Chile.

As you see the average amount of time for the four round trips was 259 milliseconds.

A millisecond is 1/1000 of second, so 259 milliseconds is just over second.

It is difficult to comprehend such rapid communication, but that extreme speed is needed for the Internet to function as it does.

A packet hops through a dozen or more routers as it moves from Los Angeles to Chile.

Like the neurons in a brain, each router has a single function that it executes very rapidly.

The routers decide which router to forward a packet to and the neurons decide whether or not to fire. 5Putting it another way

If Internet links were as slow as nerve signals, a round trip from LA to Punta Arenas would take over 59 hours.10,693kilometers

Signals move about 300,000 times faster in the brain than in a computer.

Click to play, 3:19Another brain speed exampleExcerot from Radio Lab: http://www.radiolab.org/story/91726-falling/

At about 50 minutes7Self-study questionsA millisecond is 1/1000 of a second how long is a nanosecond? A microsecond?

The distance between Los Angeles and Punta Arenas is 6,644 miles.

How long would it take an airplane flying 500 miles per hour to make the round trip?

What is the speed in miles per hour of an Internet packet traveling between Los Angeles and Punta Arenas?

Were you surprised by the level of knowledge of brain speed and function or the neuroscientist being interviewed?

Were you surprised by the speed of the Internet?

ResourcesRadiolab

Radiolab speed episode

Picking up a pen (excerpt)SpeedRadiolabPodcast, track 12013115386.305FallingRadiolabPodcast, track 12015198881.8 - AIS_AD_BREAK_1=1325500,0;AIS_AD_BREAK_2=2589000,0;XXX - AIS_AD_BREAK_1=1325500,0;AIS_AD_BREAK_2=2589000,0;