hi it's Mr wford from Ms preschool science today we're going to be looking at the reaction time required practical for biology for this you're going to need a chair a meeter ruler a table and a partner to help you with this investigation your reaction time is how long it takes for you to react to a stimulus that changes in your surroundings this will come up in the biology exam but also is mentioned in the GCSE physics relating to driving and stopping distances for this experiment you're going to need to use your weaker hand that's the hand you don't write with you need to place your weaker forearm across the day desk with your thumb and forefinger just over the edge of the desk like so this will allow your friend to drop the ruler through the Gap and you will simply close your fingers on the ruler when you detect it moving you'll need to use the corner of your eye for this and this means you have to be staring at a wall across the room you cannot look directly at the ruler your partner will hold the ruler vertically above your thumb and forefinger with the zero Mark just above your for finger they will then randomly drop it and you have to clasp your finger shut on the ruler and then record the distance traveled in your table you will do this several times and then calculate an average at the end your partner must not tell you when they're going to drop the ruler I've got my partner here who's now going to help me carry out the experiment she's going to randomly drop the ruler but now I have to focus so any kind of distraction means you won't be able to react as quickly to the ruler dropping I'm maintaining my eye contact across the room room and using the corner of my eye to make sure I'm not staring directly at the ruler the ruler lines up marked at zero just above my thumb and forefinger and then I close my fingers on the ruler as soon as I detect it start to move we then record the result which in this case would be 18 cm and we put that into our table in between experiments take a short rest otherwise you'll become too used to the movement of the ruler and you could affect the results now that I've had my short rest and we've done it once we're going to repeat this a further nine times to get 10 results in total so we can calculate a mean that time I recorded 16 cm now that I've taken my 10 measurements I converted them into reaction time using the conversion table I've then calculated an average of my reaction time which is 0.17 seconds now I've recorded my 10 results I can swap places with my partner and we can gather their results from this we can directly compare and then compare to the rest of the CL or you could compare it to yourself before and after taking a stimulant such as caffeine or sugar a common misconception is over the term Reaction Time a better reaction time is a shorter time because you are reacting faster to a stimulus