private void checkCollision() {
		for (Body b : list) {
			for (Body b1 : list) {
				int oldBodies = this.bodies;
				if (list.indexOf(b) != list.indexOf(b1) && isCollision(b.getCentre(), b.getRadius(), b1.getCentre(), b1.getRadius())) {
					if (b.getMass() > b1.getMass()) {
						b.setMass(b.getMass() + b1.getMass());
						list.remove(b1);
					} else if (b.getMass() < b1.getMass()) {
						b1.setMass(b.getMass() + b1.getMass());
						list.remove(b);
					} else {
						b.setMass(b.getMass() + b1.getMass());
						list.remove(b1);
					}

					this.bodies = list.size();
					pcSupport.firePropertyChange(BODIES, oldBodies, bodies);
				}
			}
		}

	}