Effect IA Investigate the effect of the distance between each domino on the time taken for all the dominoes to fall Independent Variable: Distance, d/CM, between each domino. The distance d/CM is measured between the middle of one domino to the middle of the next domino Dependent Variable: Time taken for all the dominoes to be toppled to the ground. The timing will start when the 1st domino is hit by a metal ball and it will stop when the last domino falls completely. Controlled Variables: 1 .

Force used to push the first domino down which sets of the chain reaction 2. Fixed wind draft 3. Angle of one domino with respect to the neighboring domino 4. Mass of one domino 5. Number of dominoes 6. Flatness of surface Controlled Variables Mass of each domino The dominoes should be of the same mass; a domino with a large mass requires more force to topple than a domino with a small mass. Therefore, the time taken for all 50 dominoes to fall will be less for a smaller mass, giving us unfair value of time taken for all dominoes to fall.

To ensure that they are of the same mass, we could use a mass balance to weigh each domino to determine if they are of equal mass (В±O. Keg) and fernier calipers can be used to determine the height of each domino block. Force applied to knock down the first domino In order to fall a domino, a force is needed to be applied to push the first block down which will then set Off chain reaction all the way to the last block.

If the force applied is not constant, it will affect the time taken for all the dominoes to fall as a greater initial force applied would mean that the 1st domino would fall faster. To obtain accurate value of time taken for all the dominoes to fall, the initial force used o push the first block down has to be constant so this way, the only factor which will affect the time taken for all blocks to fall would be the distance between them.

Therefore, one way to keep the initial push force constant would be to roll a metal ball bearing down a meter rule that is inclined to an angle of 150 by putting wooden blocks underneath it and using a protractor to ensure that the angle between surface of table and the meter rule is 150. One end of the meter rule is placed next to the always hit the 1st block with the same force. Angle of domino with respect to the neighboring domino If the dominoes are not arranged in straight line, for example, some dominoes are not parallel to each other.

The domino effect will be affected as this could mean that the distance between the dominoes might be constant throughout. The discrepancy in the distance could affect the time taken for all the dominoes to fall as the distance between each domino has an inverse relationship to the average speed of the dominoes and a shorter distance between 2 dominoes which could have arose due to the fact that the 2 dominoes are not parallel to each other could mean that the ominous would be falling at a faster rate than expected.

To ensure that this does not happen, we have to make sure that all the dominoes have been arranged in a straight line and are parallel to each other. To ensure that they are parallel, we can use 2 meter rules and place them on either side of the domino so this way we can determine if the dominoes have been arranged in a straight line. If they have been arranged in a straight line, it means that they are all parallel and the angle of one domino with respect to the neighboring one is the same.

Fixed wind draft throughout the experiment This experiment should be carried out in an enclosed space with the windows closed; this will reduce the wind draft present in the room. The wind draft will significantly affect our results as the fluctuating wind draft will cause the dominoes to fall with a greater velocity which in turns means it will fall with more momentum.

Therefore, the time recorded for all the dominoes to fall would not be accurate as the average speed that we calculated would have therefore factored in the speed of the wind. Number of dominoes The number of dominoes should be kept constant to ensure that the time taken for all the dominoes to fall is only affected by the spacing between each domino. By adding or taking away dominoes, the time taken would increase or decrease respectively as more dominoes would mean a longer total chain length.

Therefore, more time would be needed to topple all the dominoes. Thus, for each set-up, we should ensure that there is a total of 50 dominoes that are equally spaced out. Flatness of surface The surface of the lab bench has to be 100% flat to ensure that the moment of each domino tile is the same. If the surface of the lab bench is not flat, the domino might not tilted to one side, thus when this domino is struck, it will fall with a different moment as compared to other tiles that are on a flat surface.

This will cause an underestimation of the time taken for all the tiles to fall as this tile might fall faster or slower depending on the direction of the tilt, if the domino is tilted to the side where can use a spirit level gauge to find a flat surface to conduct the experiment on. We have to place the gauge flat on the surface of the lab bench and ensure that the air bubble is in the centre of the meter, showing that the surface of the lab bench which is where to dominoes are placed on is flat.

Diagram of set-up Apparatus Quantity I Apparatus I Domino | 50 Stopwatch I Meter rule I Ball bearing | 1 Wooden block Protractor 13 1 Fernier calipers | 1 Procedure 2. Set up the diagram as shown Use the meter rule to set up the dominoes in a straight row, with equal spacing of 1. CACM between them. Use fernier calipers to ensure that the gap between each domino