0:00:09.360,0:00:10.720 I'm Aloe Blacc. 0:00:10.720,0:00:14.080 I'm a singer/songwriter and entertainer. 0:00:14.080,0:00:16.840 I think computer science is really important to learn 0:00:16.840,0:00:19.240 because computer science is the future. 0:00:19.240,0:00:25.680 And I think it's important for people to be in control of the technology 0:00:25.680,0:00:29.040 that is literally controlling their lives. 0:00:29.520,0:00:34.559 To make different dance moves happen at just the right time with the music, 0:00:34.560,0:00:38.080 you can use something called events. 0:00:38.080,0:00:42.160 An event tells your program to listen for something to happen, 0:00:42.160,0:00:44.320 and then react right away. 0:00:44.320,0:00:48.800 Some examples of events are listening for a mouse click, 0:00:48.800,0:00:54.360 an arrow button, or a tap on the screen. 0:00:54.360,0:00:58.880 The event we're going to use now will listen for a change in the song. 0:00:58.880,0:01:03.640 The change will trigger your dancer to do a new dance. 0:01:03.680,0:01:10.360 Professional dancers practice their choreography by counting the beats of the song. 0:01:10.360,0:01:14.960 In music, a measure refers to a certain number of beats. 0:01:14.960,0:01:20.440 In most popular songs a measure is 4 beats long. 0:01:20.440,0:01:24.870 To get your dancers to let loose, you'll need a green event block. 0:01:24.880,0:01:30.200 This event block says after four measures. 0:01:30.200,0:01:37.240 If you drag out a purple 'do forever' block, you can pick a dance for your dancer to do. 0:01:37.240,0:01:40.840 Because it's under the after four measures event block, 0:01:40.840,0:01:46.720 your dancer will wait for four measures of the song before starting their dance. 0:01:46.720,0:01:51.100 Keep an eye on the measure counter at the top of the display area. 0:01:51.100,0:01:55.520 Look and listen for the event that will[br]trigger the dance code. 0:01:56.940,0:02:00.320 And right on cue our dancer starts going!