DC motor with potentiometer

const int MotorPin =10;
const int PotPin=A0;
int PotVal=0;
int Speed=0;



void setup ()
{
pinMode(MotorPin, OUTPUT);
pinMode (PotPin, INPUT);
Serial.begin (9600);

}

void loop()
{
PotVal = analogRead (PotPin);

Speed= map(PotVal, 0, 1023, 0, 255);
Speed= constrain(Speed, 0, 255);
Serial.println (Speed);
analogWrite (MotorPin, Speed);
}