DC Motor Speed control with potentiometer

########Code#####
int serial = 0;
int motor = 9;
void setup () {
  pinMode(motor,OUTPUT);
  pinMode(serial,INPUT);
  Serial.begin(9600);
}

void loop () {
  int sensorValue;
  sensorValue = analogRead(serial);
  delay(1000);
  float digitalValue = map(sensorValue, 0, 1023, 0, 255);
  Serial.println(digitalValue);
  analogWrite(motor,digitalValue);
  
}