Presentation on theme: "Prove it! What is proof?. Sureness Certainty How sure can we be?"— Presentation transcript:
Prove it! What is proof?
Sureness Certainty How sure can we be?
Kinds of proof Mathematical Scientific
Mathematical proof Prove that 7x3= =21 Proofs mean that you can make rules, so 7x3 is always 21
Pythagorus theorum the square of the hypotenuse=squares of other 2 sides
Pythagorus was right His logic was worked out step by step. It is completely correct because every step leads on from the last. Scientific proof is different.
The Chocolate Conjecture Eating chocolate before you do sums will make you brainer. You will be able to get more sums right! PROVE IT.
Design a good tests to investigate the chocolate conjecture This is scientific proof. We need to do a test to find out. What would you do? How would you do it?
Sums sheet 1+3 = 2+1 = 1+1= 3+2= 2+2=
Good tests Comparisons Equal comparisons – control groups Before and after Useful measurements Logical reasons for changes Placebo effects
why do we need fair tests? what happens when we dont do good tests? what could go wrong?
Why do we need fair tests?
how did we find out? science is about noticing things and thinking about WHY scientists can test ideas and find out if they are right or not this saves lives!
people used to think smoking was good for you
how did we find out that smoking harms us? science! doctors who smoked doctors who didnt smoke 50 years passed scientists compared the two groups people who smoked had more diseases and died younger
this showed smoking harmed us lots of other studies in different places showed that smoking harmed us too we are very sure that smoking is bad for us
scary statistics do you ever see scary statistics? would you like to help your mum and dad when they read newspapers?
Broomhill School Science Week 2013 ONLY £500! STOP ZOMBIES! NOW ! cut risk of ATTACK by zombies by 50% !!! BROOMHILL NEWS – science week 2013
£500 to cut the risk of zombie attack by 50% thats cutting the risk of attack in half! would you buy it?
but... cutting the risk in half with a zombie kit sounds good but what was the risk to start with? whats it half of?
100% RISK OF ZOMBIE ATTACK Means the Kit can cut the risk to 50%
But 1% risk of Zombie Attack HALF OF 1% means the kit reduces the risk of attack to 0.5% DOESNT SOUND AS GOOD!
BUT zombies DONT EXIST there is NO CHANCE OF A ZOMBIE ATTACK The Zombie Kit cuts the risk by 50% BUT HALF OF NOTHING IS NOTHING SO THE KIT IS RUBBISH
STOP 90% OF ALL PAPERCUTS! GREAT NEW INVENTION! ONLY £100!
BUT! ONLY 10 out of 1000 of children get a papercut every year if we cut the risk of papercuts by 90% instead of 10 out of 1000 children with papercuts its 1 in 1000 but you have to wear gloves all the time!
things that sound good might not be
Science is about looking, thinking and testing when we dont do fair tests, we make mistakes and harm people sometimes numbers can trick us - so we have to be careful