In aid of biology week I thought I would share something different to the standard blog- here is an experiment you can do from your own home. The experiment is designed to show kids the importance of hand washing- but is equally interesting to adults who are keen to see what is growing on their hands!
Microbes are everywhere- even on your hands. The majority of microbes living on your skin are harmless; however, they can sometimes cause disease. Proper hand washing can kill microbes found on your hands and stop the spread of infection.
Here we describe an experiment that you can do at home to see what different microbes live on your hands and how hand washing effects this.
What you will need
2 x 12 g sachet of plain gelatine
250 ml water
2 tsp sugar
4 beef stock cubes
sealable sandwich bags
What you will need to access
As with any experiment please take care. Experiments should be enjoyable and safe. Take care and ask a responsible adult to help you use the hob. Once you have infected and sealed the sandwich bags- do not open them again. Once you have had a look at the microbes- throw the plates in the bin.
Making the 'petri dishes'
In a small saucepan mix 4 beef stock cubes, 2 packs of plain gelatin, 250 ml of cold water and 2 tsp sugar
Boil the mixture and stir constantly
Once the mixture is smooth take the saucepan off the heat and allow the mixture to cool
Transfer the mixture to cupcake cases (fill each case about half way full)- these are your 'petri dishes'
Once the mix has solidified place each 'petri dish' in a sealable sandwich bag
Infecting and incubating the 'petri dishes'
Press an unwashed hand on a petri dish and reseal it in the sandwich bag, label the bag 'unwashed hands'
Wash hands using water and press your hand on a different petri dish and reseal in the sandwich bag, label the bag 'hands washed with water'
Repeat once more using hands washed with soap and water, label the bag 'hands washed with soap and water'
Leave the sealed 'petri dishes' at room temperature for 5-7 days
Examining the 'petri dishes'
Once the time is up have a look at the 'petri dishes'- do you see a difference in the microbes growing on each of the plates?
The picture above shows some of the microbes identified on the hand of an 8 year old! You could grow something very similar!
This recipe was created using the following pages: