LabLearner Discussion: Large and Small
Large and Small
Unfortunately, sometimes the coronavirus is referred to as the “invisible enemy”. Young children don’t necessarily think this means that germs are just so small that we cannot see them with the naked eye. They are as likely to conceive of “invisible” as a real property, as in invisible man or invisible superpowers. An invisible man or invisible superpowers are not real – germs are. Before young children can conceptualize the idea of germs, like bacteria and viruses, they have to come to grips with issues of size.
Before young children can conceptualize the idea of germs, like bacteria and viruses, they have to come to grips with seeing the “invisible”. Unfortunately, politicians and media sometimes refer to the coronavirus as the “invisible enemy”. Young children don’t necessarily think that means that germs are so small that we cannot see them with the naked eye. They are much more likely to conceive of invisible as a real property, as in an invisible man or invisible superpowers. These characters and superpowers are not real – germs are.
Children must realize that germs are real things that are very, very small. They are so small that we can’t even see them with our eyes alone. However, they really are there. If germs we truly invisible, not having a physical form, there would be no way of killing them or washing them off our hands – because they wouldn’t really exist. Therefore, in this discussion we will focus on the idea that some things are very, very small… but they are still really there and very real!
This slide shows something small and something large. Adults know that no matter how small or how large, there is always something smaller or larger. Ultimately perhaps, the largest thing is the Universe while the smallest things are smaller than atoms or electrons and may be something referred to as “strings”. This is well beyond a young child’s ability to comprehend. Nonetheless, even adults cannot truly conceptualize either extreme of the size spectrum.
This slide, in a comical way, depicts something small and something large. Discuss other things that are small versus large with your child. Important concepts are embedded in terms like larger, bigger, smaller, same, biggest, largest, smallest, and so on.
This fun slide introduces the concept that there is always something smaller if we look harder. Begin by looking at the little baby’s foot at the top. Ask, “Is there anything smaller than the little foot in this picture?” Next, discuss the sand on the foot (center image). Also, you might ask, “What is something even smaller than this baby’s foot?” One answer, of course, is the baby’s toes!
The image at the bottom introduces the idea that, to see things very small, they can be magnified by the use of equipment like the microscope. The sand grains at the bottom were obtained using a scanning electron microscope.
This slide shows a scientist or doctor using a microscope. It is a light microscope, meaning that light (at the bottom) is passed up through the specimen and into glass lenses. For very young children, differentiating between types of microscopes may be confusing. Just refer to these instruments as microscopes. In the LabLearner curriculum, students do not use microscopes until fourth grade. Before that, however, they use hand lenses.
You may finish this slide by asking your child what they would want to look at with a microscope. When they reply, ask them, “What do you think you would see if you looked at that?”. The point is to have your child consider things smaller than they can see with an unaided eye. Once again, we are attempting to develop the notion that some things (like germs), even though they really do exist, are too small to see with our eyes alone.
This image is the first of two fun examples. While looking at this slide, have your child try to guess what the magnified (or enlarged) image is of. This photograph was not captured through a microscope but rather a macro camera lens.
It is the surface of a strawberry! Go back and forth between this and the previous slide to establish the relationship between the two images. Importantly, point out that certain structures like the “stem” of the seed cannot even be seen without magnification.
While looking at this slide, have your child try to guess what the magnified image is of. Once again, this photograph was not captured with a microscope but rather a macro camera lens.
It is a picture of sprinkles on a donut! Go back and forth between this and the previous slide to establish the relationship between the two images. Talk about what other things around the room might look like if they were increased in size (magnification).
This slide adds mathematics to the discussion. Young children may not be familiar yet with either metric measurements or decimals. These are two areas for further discussion for students in the later primary grades. Nonetheless, discuss that a red blood cell is about 100 times smaller than even a single grain of sand. After discussing this slide, you might want to return to Slide 3 and discuss that there are things much smaller than even the grains of sand on the little baby foot.
Red Blood Cells (RBCs) carry oxygen to all of the tissues in our body after passing through the lungs. These simple and important cells are discussed further in the next slide.
This rather complex slide can inspire many topics of discussion. Children become aware of blood at an early age. Naturally, they consider it to be a red liquid, like cherry juice or powdered drink. However, the liquid component of blood isn’t red at all. The liquid part of blood, plasma, is light amber. The red color of blood comes from the small cells floating in the plasma, the RBCs. These cells could not be visualized until the invention of microscopes and it was in the mid-seventeenth century that the Dutch microscopist, Antoni van Leeuwenhoek, made the first drawings of these cells near the end of the century:
The significant point of discussion with your child should be the concept that a physical “particle”, far too small to see with the naked eye, is responsible for the color of blood. It’s a difficult concept to grasp, even for adults.
Most homes have an inexpensive hand lens available. If not, a pair of reading glasses can often provide usable magnification. Ask your child to use the lens to look at three (or more) objects. They can draw a picture of what they see if they wish.
Discuss what your child saw using a hand lens. Ideally, your discussion should aim at discerning differences between what an object looks like without and with magnification. Typically, one noticeable difference, even at relatively low magnification, is the surface texture of an object. Examples include items like a basketball, fingertip (finger prints), orange skin, or pencil point. Looking at a photograph in a magazine or newspaper with a hand lens easily discloses the pixilated nature of the image.
All of these examples should be focused on having your child begin to appreciate the “hidden” details in the world around them. Germs, like bacteria and viruses, will be introduced in a later LabLearner Discussion in this series. That discussion will be predicated on the idea that extremely small things, although they might not be visible to the naked eye, are real and do exist.
The final two slides are, as labeled, based on a silly magnification joke.
No comment necessary. Nonetheless, stress to your child that there is ALWAYS something smaller than they can see. Note: Ants obviously do not have teeth like this… it’s a joke!
Large and Small: Relevant LabLearner CELL Curriculum Units
Health and Hygiene
The Human Body
Microscopes & Magnification
Light & Optics