Wash Your Hands!

Jarod Macarthur

Kindergarten Macarthur Homeschool

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Introduction Mummy always tells me to wash my hands before eating to kill germs so they don’t go into my tummy and get sick! But why do I need to wash my hands and why do I need to use soap? I wanted to find out if washing hands do kill all the germs.

What is Germs Germs can be bacteria or viruses. They are called microbes as they can only be seen under the microscope, as they are too small to see with our eyes. Most do not hurt us, but some can make you sick. They are in the air, on our skin, in our bodies and in the ground. Some bacteria are good. They are used in yoghurt, bread and even help with our digestion. Bad bacteria can make us sick. It can enter our body through open cuts, nose and mouth. The white blood cells in our body fight bacteria by shooting antibodies at them. There are 3 types of bacteria. They are straight shaped bacteria called bacilli, sphere shaped bacteria called cocci and spiral shaped bacteria called spirilli.

Hypothesis I think the side with washed hands with soap has less bacteria colonies than the side without washing hands on the petri dishes. So Side B should have less bacteria blobs or colonies than Side A. I think that washing my hands with soap will kill the germs so they don’t go into my tummy when I eat.

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Material

2 Petri Dishes with agar Lots of Germs Palmolive Antibacterial Hand Wash

Experiment Design The variable that I am going to keep the same is my hands. The variable that I am going to change is whether my hands are washed with soap or not. I also used 2 petri dishes so I could do the experiment two times; to make sure the results are the same. I also made sure that I didn’t open the lids so that no other bacteria or germs could get onto the agar to contaminate the experiment.

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Procedure

1. I made the agar for the petri dish. Agar helps the bacteria to grow. a. I add some agar to 90mls of water to a pot and stir b. Boil the mixture c. Continue to stir until the agar is dissolved and the mixture is clear d. Add the bouillon and heat and stir until dissolved e. Pour into the Petri dishes f. Add lids to the Petri dishes and let it cool. When the agar cools, it

will harden like gelatine.

2. Mummy drew a line down the middle of each of the petri dishes into two halves, and label one side A, and one side B

a. Side A will be the unwashed hands b. Side B will be after washing my hands with antibacterial foam soap

3. I gently put two fingers into the petri dish on side A

4. I then washed my hands with soap and wiped my hands dry

5. I was careful not to touch anything, and gently put two fingers into the

petri dish on side B.

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6. I covered the petri dish with the lid, and labelled them 1 and 2

7. I then put the petri dishes on top of the fridge, where they would remain

dry and warm.

8. I then checked the petri dishes every day to see if there were any bacteria growing. I counted the number of blobs known as colonies on the dishes.

9. I checked them everyday for 2 weeks to see what would happen. I recorded them down in a table.

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Results I counted the number bacteria colonies (individual spots and blobs) on each side of the petri dishes each day for 2 weeks. This is recorded in the tables. Petri Dish 1 A (Unwashed) B (Washed with Soap) Day 1 22/7/15 0 0 Day 2 23/7/15 20 3 Day 3 24/7/15 25 5 Day 4 25/7/15 34 5 Day 5 26/7/15 52 13 Day 6 27/7/15 57 14 Day 7 28/7/15 61 18 Day 8 29/7/15 79 24 Day 9 30/7/15 82 28 Day 10 31/7/15 85 31 Day 11 1/8/15 89 37 Day 12 2/8/15 93 42 Day 13 3/8/15 95 46 Day 14 4/8/15 107 55

Petri Dish 2 A (Unwashed) B (Washed with Soap) Day 1 22/7/15 0 0 Day 2 23/7/15 8 2 Day 3 24/7/15 15 6 Day 4 25/7/15 22 6 Day 5 26/7/15 34 9 Day 6 27/7/15 37 14 Day 7 28/7/15 42 19 Day 8 29/7/15 57 23 Day 9 30/7/15 72 27 Day 10 31/7/15 84 30 Day 11 1/8/15 87 46 Day 12 2/8/15 96 59 Day 13 3/8/15 101 67 Day 14 4/8/15 114 75

My mummy helped me take photos of the petri dishes to show how much they have grown over time. We also put the petri dishes under the microscope to see what the different bacteria looked like close up. It was really interesting to look at. We took photos of them.

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These are the photos over time over the 2 weeks.

25th July 2015- Day 4

This is what they looked like on day 4 of the experiment. Bacteria had started growing. There were a lot more blobs on Side A of Petri- dish 1 compared with Petri-dish 2.

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31st July 2015- Day 10 More bacteria have grown in the petri dishes in both 1 and 2. I’m not sure exactly what the orange area is on petri dish 1. I don’t think it is bacteria, as it isn’t growing in size.

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This is Petri Dish 1 and 2 with bacteria enlarged under the microscope.

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4/8/15- Day 14

This is the final day of counting for my experiment. This is what the 2 petri- dishes looked like at the end of the 2 weeks.

The bacteria have definitely grown over the 14 days from nothing to lots of different bacteria colonies. Side A with the unwashed hands has a lot more bacteria than Side B with the hands washed with soap.

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Discovery We wanted to see the growth rate of the bacteria in each of the petri dishes and how the dirty hands (unwashed) compared with the clean hands (hands washed with soap). We put the results into excel and made a line graph of how the bacteria grew. This is Petri-Dish A

This is Petri-Dish B

Bacteria grew for both washed and unwashed hands. The bacteria on Side A (the unwashed hands) grew a lot faster than Side B (hands washed with soap).

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Comparing the number of bacteria colonies in Petri-dish 1

Comparing the number of bacteria colonies in Petri-dish 2

From the bar graphs above, we can compare the number of bacteria colonies between the wash and unwashed hands. There were a lot more bacteria from the unwashed hands compared to washed hands. We found that over time, the small blobs joined together to form big bacteria colonies. There was not much growth of bacteria from the 24/7 to the 25/7 as Daddy left them on the kitchen bench and forgot to put it back up on the top of the fridge where it was nice and warm for them to grow.

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B (Washed with Soap)

A (Unwashed)

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Investigation The results have shown that there definitely are less bacteria on Side B where I have washed my hands with soap compared with Side A where I did not wash my hands. But why? Washing our hands with soap does not kill the bacteria. When we wash our hands the soap chemically works to break down the oil, while the friction from rubbing does it mechanically. Thus, the more soap and the longer the hands are rubbed together, once rinsed away with water, the less oil and microbes left on your hands. This is a good way of removing bacteria even though the bacteria doesn’t die, but is simply flushed away when you wash. Hand washing with soap is important because it removes germs from hands. This helps prevent infections because:

People frequently touch their eyes, nose, and mouth without even realizing it. Germs can get into the body through the eyes, nose and mouth and make us sick.

Germs from unwashed hands can get into foods and drinks while people prepare or consume them. Germs can multiply in some types of foods or drinks, under certain conditions, and make people sick.

Germs from unwashed hands can be transferred to other objects, like handrails, table tops, or toys, and then transferred to another person’s hands.

Removing germs through hand washing therefore helps prevent diarrhea and respiratory infections and may even help prevent skin and eye infections.

So the correct method of washing our hands is:

1. Wet your hands with clean, running water and apply soap. 2. Rub your hands together with the soap. Be sure to rub the backs of your

hands, between your fingers, and under your nails. 3. Scrub your hands for at least 20 seconds. 4. Rinse your hands well under clean, running water. 5. Dry your hands using a clean towel or air dry them.

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Conclusion I discovered that washing your hands really do reduce the number of bacteria. The side with unwashed hands had a lot more bacteria than the side where the hands are washed with antibacterial soap. So washing hands with soap washes the bacteria and other microbes away. I was so surprised at how much bacteria had grown in the petri dishes. I was very disgusted at how dangerous and scary they looked. They grew very fast. Keeping hands clean is one of the most important steps we can take to avoid getting sick and spreading germs to others. Many diseases and conditions are spread by not washing hands with soap and clean, running water. I will definitely be washing my hands before I eat every time! I don’t want bad bacteria like them growing in my tummy.

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Reference The Magic School Bus- Inside Ralphie. 1994. DVD. Egan, Kate, Carolyn Bracken, and Joanna Cole. The Magic School Bus Fights Germs. New York: Scholastic Inc., 2008. Print. Science for Kids: Bacteria and Germs. 2015. Science for Kids: Bacteria and Germs. [ONLINE] Available at:http://www.ducksters.com/science/bacteria.php Cdc.gov,. 'Show Me The Science - Why Wash Your Hands? | Handwashing | CDC'. N.p., 2015. Web. 9 Aug. 2015.

Acknowledgements A big thank you to Mummy and Daddy for the big help they gave me (and for letting me grow germs in the house!) Also for teaching me that I really do need to wash my hands as there are bacteria everywhere. A huge thank you for Mummy helped me type up this project and for teaching me all about bacteria. Also for helping and teaching me take photos of my petri dishes and showing them to me under the microscope. Thank you to Daddy for helping me count together the number of bacteria spots called colonies.