I am a Christian. I was an 8th-grade American History teacher. I am currently a freelance writer, public speaker, & homeschooling mom of 9.
This is part 7 of a 7 part hands-on unit study on anatomy of the human body. Make an edible layers of skin model, play immune system freeze tag, watch how germs spread, observe bacteria under a microscope, and more! These lessons are geared toward 4th-5th grade level children and their siblings and were created for our weekly homeschool co-op class. We meet each week for 2 1/2 hours and have 33 children between the ages of 1-13. Use these fun lessons with your classroom, family, after school program, camp, or co-op!
Introduction & Germs Spreading
1. Have each child rub hand lotion on their hands & then sprinkle a couple shakes of glitter onto their hands. (Don't tell them why you are doing this. You'll explain later.)
YOU WILL NEED: hand lotion & glitter
2. Pray. Read & discuss 2 Kings 5:1-14.
3. Review the systems of the body and introduce the Integumentary (skin, hair, & nails) and Lymphatic (immune) Systems.
Integumentary System: Your Skin
4. Discuss how skin helps us: prevents germs from entering our bodies, produces Vitamin D, regulate our body temperature, protects us from the harmful rays of the sun, keeps the water our body needs from evaporating, and gives us information through our sensory neurons.
- Have children examine their skin and determine where their skin is thickest, thinnest, most wrinkled, and moistest. Briefly mention how the protein, elastin, allows skin to wrinkle and then become smooth again on places such as your elbows and knuckles.
- Discuss pigments. Have children determine who has the lightest skin and the darkest skin. Discuss the role of the pigments carotene and melanin.
YOU WILL NEED: mirrors (such as a compact mirror) (optional)
Labeling Layers and Parts of the Skin
5. Lead children in coloring and labeling the layers of their skin. Briefly discuss each part and its function. A free printable worksheet for children to color that shows the layers of skin is http://www.enchantedlearning.com/ (as shown in the photo). If you would prefer a labeled worksheet for children who cannot write quickly, you can use http://wikieducator.org/ .
YOU WILL NEED: crayons/markers/colored pencils and layers of skin worksheets
Protection Against Germs
6. Reveal to the children why they had glitter on their hands. This was an experiment to show how germs spread. Have the children use mirrors to see all the glitter on their faces. Allow them to quickly walk around the room to see where the glitter is. Then discuss the best way to kill germs: washing your hands regularly with soap and warm water. Have the children wash their hands.
YOU WILL NEED: mirrors (such as compact mirrors) and soap
Edible Skin Layers
7. Now that the germs have been washed away, we are ready to make the edible model of the layers of our skin. Review the layers of our skin and its parts as you create the edible model of the layers of our skin in cups.
- The hypodermis or subcutaneous tissue (fat) will be represented by 4-6 slices of banana.
- The dermis layer will be represented by red jell-o made with strawberries (which represent nerve endings and capillaries) and grape pieces (which represent sweat glands).
- The epidermis layer will be represented by a fruit roll-up. Before placing it on top of the jell-o dermis layer, make 3 small slits in it so that your hair can fit through those holes.
- Now push your licorice hair through your epidermis into your dermis layer, where it can sit in its hair follicle.
- Review what each part represents, and then allow children to eat their edible layers of the skin (or give them to their parents to save for later if desired).
YOU WILL NEED PER CHILD: 1 plate, 1 spoon, 1 clear disposable cups (small or medium size), 4-6 banana slices, red jell-o made with diced strawberries and grape pieces, 1/4 of a fruit roll-up (preferable yellow or orange -- and preferably cut into a circle, and 3 small strips of chocolate or black licorice [each about 1 inch]
(This idea is a slightly revised version that originally came from http://fromthemrs.blogspot.com/2013/07/human-anatomy-science-units-for-kids.html .)
Integumentary System: Your Hair and Nails
8. Lead children in examining their hair: color, cow licks, and whorls. Briefly discuss how hair grows and its parts. Have children examine their nails. Briefly discuss how they grow and their parts.
YOU WILL NEED: a mirror (such as a compact mirror)
The Lymphatic System & Bacteria
8a. Ask, “What are germs?” [Allow children to answer.]“Germs,” also called pathogens, include bacteria, viruses, fungi, & protozoan. They are microscopic foreign invaders that cause harm to our cells and make us sick.
- Ask, “Are all bacteria bad?” [Allow children to answer.] Only about 5% of bacteria makes you sick. The other 95% are either harmless or essential for you to be healthy. [I showed a bag of 100 crayons and pulled out 5 in order to have a visual of this.] Who can name some examples of good bacteria? (bacteria in your large intestine, bacteria in yogurt, penicillin, etc.)
- Ask, “What does infectious mean? How do we get infected? What are some examples of noninfectious diseases?”
YOU WILL NEED: a bag of 100 crayons (or 100 of any other item)
Bacteria's 3 Main Shapes
8b. (Optional) Quickly discuss bacteria’s 3 main shapes by showing pictures of them. Then lay out a handful of craft pompoms and pipe cleaners and have children hold up the shape when you say the name:
- Cocci - sphere-shaped (craft pompom)
- Bacilli – rod-shaped (pipe cleaner cut into a small rod)
- Spirelli – spiral-shaped (pipe cleaner curved into a spiral)
YOU WILL NEED: a picture of the 3 main shapes of bacteria, craft pompoms, & pipe cleaners (some cut into small rods and some shaped into spirals)
How Germs Spread
9. One way germs are transmitted from one person to another is through sneezing and coughing.
- Demonstrate this by partnering up children. Let each child have a turn pretending to sneeze or cough while using a spray bottle to squirt ONE squirt of water on a sheet of newspaper or other larger paper.
- Have children reverse rolls and allow the other person to pretend to sneeze or cough while spraying one squirt of water onto a paper held by the other child.
- The liquid represents your saliva full of germs that shoots out when you sneeze or cough. A single sneeze can blow 100,000 drops into the air. Other people inhale them and catch a cold themselves.
- This is why it is important for you to sneeze or cough into the crook of your elbow (or into a tissue). Have children pretend to sneeze and cough into the crook of their elbows. Why shouldn't you use your hand? (Remember the glitter? You'll cough or sneeze your germs onto your hand, and then touch the germs to door handles, light switches, etc.)
YOU WILL NEED: a sheet of newspaper or larger paper like a grocery store ad per child and one or more spray bottles with water
How Your Body Battles Germs
10. Read one of the below books on how pathogens invade your body and make you ill and how our immune systems fight back. We read “Your Body Battles a Skinned Knee” by Vicki Cobb.
YOU WILL NEED: a picture book on the immune system such as “Your Body Battles a Cold” by Vicki Cobb
Our Favorite Picture Book on the Immune System for Reading Aloud
Lymphatic System As a Filter
11. Briefly discuss how the lymphatic system works as a home for your lymphocyte army and as a filter. If desired, pour water into a water filter to give them a visual aid. Also briefly discuss about lymph nodes and have children feel theirs under their jaw lines.
YOU WILL NEED: water filter (such as a Brita water filter pitcher) (optional) and a picture of the lymphatic system (optional)
How Bacteria Multiply
12a. Have each child hold up the colored sheet of paper. Tell the children that this is bacteria that got into their bodies. As soon as bacteria enter your body, they begin to divide and multiply rapidly by binary fission. Bacteria double about every 30 minutes.
- Have everyone tear their colored sheet in half. Let’s pretend 30 minutes have passed. The bacteria divide again. Have them tear the 2 colored sheets of paper in half. Now they have 4 pathogens.
- The bacteria divide again. Have them tear the 4 colored sheets of paper in half so that they have 16 sheets of paper.
- Tear all the colored sheets in half again to get 32 pieces of paper. (You may have to not tear them all at once at this point. Simply tear a few at a time but make sure to tear each sheet of paper in half.)
- Ask, “How many bacteria would you have if you divided them again?” (64)
- “If it divided again?” (128)
- In just 5 hours, 1 bacteria will turn into 1,024 bacteria!
- Have the children pile all their sheets of paper into one pile.
- Remember that when bacteria entire your body, it’s not just this one bacteria. It is many thousands of them, and they are each dividing this way.
YOU WILL NEED PER CHILD: 1 sheet of colored paper (Helpful hint: Yellow lined paper from a legal notepad is much easier to tear than construction paper.)
White Blood Cells Multiply Quickly Too
12b. Thankfully your immune system does the same thing. Have the child get out their white paper. This white paper represents a white blood cell in your body.
- Have the children again tear the paper in half.
- Tear those pieces of paper in half.
- Tear all those pieces of paper in half.
- Tear all those pieces of paper in half.
- Your white blood cells divide just as quickly to attack and kill the bacteria. Place the “immune system” sheets of paper over the pile of the “bacteria” sheets of paper.
YOU WILL NEED PER CHILD: 1 sheet of white paper (Helpful hint: Yellow lined paper from a legal notepad is much easier to tear than construction paper.)
How Viruses Replicate Themselves
13. Viruses are different.
- Show pictures of different types of viruses.
- Scientists agree that bacteria are alive, but they do not consider viruses to be alive. Viruses can move on their own, but they cannot reproduce without a host cell.
- Once a virus gets inside your body, it tricks your cell membrane into letting it inside your cell. [Drop a pompom into a balloon that's been pre-filled with craft pompoms.]
- Once it invades your cell, it takes over the nucleus and has your cell’s nucleus begin reproducing the virus. [Begin blowing up the balloon & then tie it off.]
- Eventually so many viruses are created, they blast out of the cell, destroying it. [Pop the balloon.]
- Those viruses then each look for a cell to trick, invade, & take over. But have no fear. Your immune system is at work killing off the viruses.
- (Optional) Briefly discuss how traditional vaccines work.
YOU WILL NEED: pictures of different shapes of viruses, a craft pompom, a balloon that's been pre-filled with craft pompoms, and a sharp object for popping the balloon
Immune System Tag
14. Play Immune System Tag. (Note: If you are limited by time or are working with only younger children, you can act this out using props like toy swords and helmets instead of playing the tag game.)
- Divide children into 3 groups. Give 1/3 of the children a name-tag with a person drawn on it. These children will represent people. Give the next 1/3 of the children name-tags with rod drawn on it. They are going to be salmonella bacteria. The third group of children will have name-tags with a puff-ball shape on them. They are going to be the white blood cells.
- The white blood cells are supposed to protect the people.
- The "people" will run around in an open space.
- If a "salmonella bacteria" touches a person, that person becomes ill and must sit down.
- The "white blood cells" can "heal" a sick person who is still down by touching them.
- When a person sitting down is tagged by a person who has a "white blood cell" sticker, they can run around again.
- The "white blood cells" will also try to destroy the "salmonella bacteria" players.
- If a "white blood cell" player tags a "salmonella bacteria" player, the "salmonella bacteria" is out of the game and must sit over to the side.