diff --git a/src/activities/intro_gravity/intro_gravity.js b/src/activities/intro_gravity/intro_gravity.js
index 0ef24bb96..68783b7d9 100644
--- a/src/activities/intro_gravity/intro_gravity.js
+++ b/src/activities/intro_gravity/intro_gravity.js
@@ -1,219 +1,220 @@
 /* GCompris - intro_gravity.js
 *
 * Copyright (C) 2015 Siddhesh suthar <siddhesh.it@gmail.com>
 *
 * Authors:
 *   Bruno Coudoin <bruno.coudoin@gcompris.net> and Matilda Bernard (GTK+ version)
 *   Siddhesh suthar <siddhesh.it@gmail.com> (Qt Quick port)
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, see <http://www.gnu.org/licenses/>.
 */
 .pragma library
 .import QtQuick 2.0 as Quick
 .import GCompris 1.0 as GCompris //for ApplicationInfo
 .import "qrc:/gcompris/src/core/core.js" as Core
 
 var url = "qrc:/gcompris/src/activities/intro_gravity/resource/"
 
 var currentLevel = 0;
 var numberOfLevel = 4;
 
 // delta move
 var move
 
 //array of created asteroids
 var asteroids = new Array;
 var asteroidsErased = new Array;
 
 var minDuration = 20000
 var asteroidCounter
 
 var items;
 var message;
 
 function start(items_,message_) {
     items = items_
     currentLevel = 0
     message = message_
     initLevel()
 }
 
 
 function stop() {
     items.timer.stop()
     items.asteroidCreation.stop()
     items.shuttleMotion.stop()
     destroyAsteroids(asteroids)
     destroyAsteroids(asteroidsErased)
     asteroidCounter = 0
 }
 
 function initLevel() {
     items.bar.level = currentLevel + 1
 
     stop()
 
     items.scaleLeft = items.planetLeft.minimumValue + 0.2 * currentLevel
     items.scaleRight = items.planetRight.minimumValue + 0.2 * currentLevel
     items.spaceship.source = url + "tux_spaceship.svg"
     items.spaceshipX = items.background.width / 2
 
     move = 0
 
     items.shuttle.x =  Math.random() > 0.5 ?
                 items.background.width * 0.2 : items.background.width * 0.7
     items.shuttle.y = items.background.height + items.shuttle.height
 
     if(items.bar.level != 1 ) {
         items.timer.start()
         items.asteroidCreation.start()
         items.shuttleMotion.restart()
         message.index = -1
     } else {
         message.index = 0
     }
 }
 
 function nextLevel() {
     if(numberOfLevel <= ++currentLevel ) {
         currentLevel = 0
     }
     initLevel();
 }
 
 function previousLevel() {
     if(--currentLevel < 0) {
         currentLevel = numberOfLevel - 1
     }
     initLevel();
 }
 
 
 function repositionObjectsOnWidthChanged(factor) {
     if(items) {
         initLevel()
     }
     for(var i = asteroids.length - 1; i >= 0 ; --i) {
         var asteroid = asteroids[i];
     }
 }
 
 function repositionObjectsOnHeightChanged(factor) {
     if(items ) {
         initLevel()
     }
     for(var i = asteroids.length - 1; i >= 0 ; --i) {
         var asteroid = asteroids[i];
     }
 }
 
 
 // functions to create and handle asteroids
 function createAsteroid() {
 
     var asteroidComponent = Qt.createComponent("qrc:/gcompris/src/activities/intro_gravity/Asteroid.qml");
     var ImageUrl = url + "asteroid" + Math.floor( Math.random() * 5  ) + ".png"
 
     var randomX = items.background.width * 0.2 +
             Math.random() * (items.background.width - items.background.width * 0.4)
 
     var fallDuration = minDuration - Math.floor(Math.random()* 1000 *(currentLevel+1))
 
     var asteroid = asteroidComponent.createObject(
                 items.background,
                 {
                     "source" : ImageUrl,
                     "x": randomX,
                     "y": 50,
-                    "fallDuration": fallDuration
+                    "fallDuration": fallDuration,
+                    "scale": GCompris.ApplicationInfo.ratio
                 });
 
     if(asteroid === null) {
         console.log("error in creating the asteroid object")
     }
 
     asteroids.push(asteroid);
     asteroid.startMoving()
     asteroidCounter++
 }
 
 function destroyAsteroids(asteroids) {
     for(var i = asteroids.length - 1; i >= 0 ; --i) {
         var asteroid = asteroids[i];
         // Remove the asteroid
         asteroid.destroy()
         // Remove the element from list
         asteroids.splice(i,1)
     }
 }
 
 
 function movespaceship(){
     move += ( items.forceRight - items.forceLeft) / 10000 * items.bar.level
     items.spaceshipX += move
 
     // Manage the crash case
     if(items.spaceshipX < 200 * GCompris.ApplicationInfo.ratio)
         crash()
     else if(items.spaceshipX > items.background.width - 200 * GCompris.ApplicationInfo.ratio)
         crash()
 
     // Manage to get into shuttle
     var shuttleY = items.shuttle.y + items.shuttle.height / 2
     var shuttleX = items.shuttle.x + items.shuttle.width / 2
     if(shuttleY > items.spaceshipY - items.spaceship.height / 2 &&
             shuttleY < items.spaceshipY + items.spaceship.height / 2 &&
             shuttleX > items.spaceshipX -items.spaceship.width / 2 &&
             shuttleX < items.spaceshipX + items.spaceship.width / 2) {
         items.bonus.good("flower")
         items.spaceship.source = ""
         stop()
     }
 }
 
 function handleCollisionWithAsteroid()
 {
     if(asteroids !== undefined){
         for(var i = asteroids.length -1 ; i >= 0 ; --i) {
             var asteroid = asteroids[i];
             var x = asteroid.x + asteroid.width / 2
             var y = asteroid.y + asteroid.height / 2
 
             if(y > items.background.height) {
                 asteroid.destroy()
                 asteroids.splice(i,1)
             } else if(y > items.spaceshipY - items.spaceship.height / 2 &&
                       y < items.spaceshipY + items.spaceship.height / 2 &&
                       x > items.spaceshipX - items.spaceship.width / 2 &&
                       x < items.spaceshipX + items.spaceship.width / 2 ) {
                 asteroid.destroy()
                 asteroids.splice(i,1)
                 crash()
                 return
             }
             if(asteroidCounter == 4) {
                 items.bonus.good("flower")
                 stop()
                 return
             }
 
         }
     }
 }
 
 function crash() {
     items.audioEffects.play("qrc:/gcompris/src/core/resource/sounds/crash.wav")
     items.spaceship.source = url + "crash.svg"
     stop()
 }