ingridscience

Set-up prior to experiment: a box magnifier or small clear dish, the bottom lined with damp tissue and containing a live wood bug, for each student.
For biomes lesson, keep wood bugs in their habitat, and provide magnifiers.

If using them, show students how to use magnifiers.

Keeping the wood bug sealed in the container, students look at them closely, and draw what they see (not what they think they should see). Sometimes they will see a feature that they don't know what it is, but that is OK.
Class discussion, led by what students notice. Points to include: colour, body parts of wood bugs, and how each of these might help the wood bugs survive.

Wood bug information:
They are a colour that makes them well camouflaged in the dark brown and grey places they are often found. Wood bugs have 14 legs - they are crustaceans. Wood bugs have antennae for feeling around and smelling. They have an exoskeleton to protect them, which is segmented. Only some wood bug species are able to roll into a ball. Wood bugs are closely related to (and evolved from) ocean-living crustaceans such as shrimp (thought to have colonised land in the Carboniferous period). Like the ocean animals they are related to, they have gills - using them to extract oxygen from water (the gills are the flat white structures underneath near the tail). Because of this, they always need to be in a moist environment, and will die fast if they dry out. They are decomposers, an important animal in food chains, eating dead plant and animal matter and turning it into soil.
More info: https://www.thoughtco.com/fascinating-facts-about-pillbugs-4165294
Video about pillbug evolution from ocean crustaceans: https://www.pbs.org/newshour/science/pill-bugs-emerged-sea-conquer-earth also at https://www.youtube.com/watch?v=sj8pFX9SOXE

Sometimes the eggs under the female can even be seen.

For my lessons, I believe I found wood bugs from these three families: Armadillidiidae (pill bugs, which roll into a ball), Oniscidae and Porcellionidae. Reference: http://en.wikipedia.org/wiki/Woodbug General information on wood bugs, including photos.

Wood bug images (including babies) in this article: https://entnemdept.ufl.edu/creatures/MISC/Armadillidium_vulgare.htm
Wood bug moulting images: https://www.researchgate.net/figure/Molting-A-Armadillidium-vulgare-aft…

Vocabulary:
wood bug: a familiar animal with 14 legs and a hard exoskeleton; a crustacean that lives on land
crustacean: a large group of animals, segmented with an exoskeleton, mostly aquatic (e.g. shrimp, crab)
exoskeleton: an outer protective shell, found on animals that do not have bones
antennae: feelers at the front of the body, used for feeling and smelling surroundings
habitat: a place for a living thing to live

For outdoor wood bug habitat hunt:
Students to look for wood bugs, and record where they find them and the conditions (damp/dry, light/dark, warm/cool).
From their data, conclude where wood bugs like to live, and what conditions provide an ideal habitat for them.

For indoor classroom activity:
Set-up prior to experiment: at least one hour before students come into class, set up a habitat on each table group. Each habitat is a clear container with a layer of damp sand on the bottom, a chunk of rotten wood, a rock and five or so wood bugs.
For the lesson, provide each table group with a number of sticky notes corresponding to the number of wood bugs in their habitat. At their desks, each group counts how many of their their wood bugs are under the wood, how many are under the rock and how many are out on the open sand - they will need to gently lift the items to find all the wood bugs.
Students record their results by using one stickie per wood bug, and writing where they are on it (sand/wood/rock). Each group adds their sticky notes to form the columns of a class bar chart.

A classroom discussion with the bar chart determines where the wood bugs most like to live. Usually the wood is preferred over the rock. Why? The wood is a shelter for the wood bugs - it is a dark hiding place. The wood is also a little moist, so keeps the wood bugs damp. (Wood bugs get oxygen from water with their gills - they don't have lungs - so they always need to stay in damp places to survive. They evolved from animals that lived in the ocean, and have retained their gills unlike many other land animals.) In addition, the wood bugs might like to eat the wood.
Wood bugs are also often found on the sand, or maybe burrowed into it. The sand is damp, which they prefer.
Usually the wood bugs are not found under the dry rock, though sometimes they are.

Then ask students to modify the habitats to make them the best for the wood bugs - the rocks can be removed if wood bugs were not found under them, or left if they were. If a lot of wood bugs were found under the wood, add more wood pieces to each habitat. Whatever the results, the sand should be kept in the habitat as it will keep the environment damp.

Conclude that we have given the wood bugs a shelter that serves their needs. If the wood bugs are to be kept in the classroom, they will need food as well - either conduct an activity to determine what wood bugs like to eat, or alternatively, after discussion that wood bugs eat dead plant matter add some wilted lettuce or potato to the habitat.

Introduction:
Nurse logs are formed when a tree falls over, or from the stump of a tree that was felled, and provide an environment for other things to grow. As the log decomposes it provides food and a habitat for many animals and plants. In coniferous forests (e.g. Pacific Northwest Coast) rotting logs provide many of the nutrients of the forest floor.

Some of the photos above show nurse logs that have decomposed completely, leaving only the shape of the roots of the trees that grew on it.
For this activity, find a nurse log that has some of its stump remaining.

Ask students to draw the nurse log, and anything they see growing out of it, or any evidence of life living on it. They can shade in the nurse log (to highlight how much is consumed by the new trees). Examples of living things they might find on a nurse log: hemlock and douglas fir saplings, small huckleberry bush, sword fern or other ferns, lichen, spider webs, bird poop, insects, holes made by insects and birds.
Ask students to smell the wood - the mushroomy smell is fungus growing through the log.

Group discussion of what everyone found, and students can add more items to their drawings, and label anything they did not know the name of.

Use a large sheet of paper or a board, and write "nurse log" at the bottom. This will be the start of a food web. Add in the other names of living things found, with arrows to show who eats who e.g. nurse log eaten by insects, plants, fungi and lichen; insects eaten by spiders and birds; spiders eaten by birds.

More information on nurse logs and how they help seedlings survive: https://asknature.org/strategy/nurse-logs-provide-new-habitat/

Students can collect their own items to look at and/or teachers can provide objects.

Ideas of things to look at:
Your own skin, fingerprint, hair, nails.
Man-made items such as fabrics with different weave densities, paper with different texture and colour printing (to see the individual coloured dots).
Natural organic items such as fur, wood, feathers and seeds.
Natural inorganic items such as crystals (including salt) and rocks with different mineral colours in them.
Living samples such as pond water or soil containing small animals.

A microscope can be set up in the classroom, or outside if power can be run outside.
If any collected specimens are animals, students should ask an adult to help them put it in a collecting with some dirt and/or leaves, and return it to the same place after class.

A sequential magnification of specimens, from looking closely with the naked eye, to looking with a magnifier, to looking with a microscope, give a good sense of what is being looked at. What can you see with the magnifiers that you were not able to see with your naked eye? What were you able to see with the microscope that you were not able to see with the magnifier? It also creates a wonderful zoom into the details upon details in objects - there is so much going on that we don't usually see, and understanding the structure in more detail can help us understand function.

Proper use of magnifiers
Great for younger students.
Hold the magnifier 5-8cm from one eye, and look through it. Hold a finger on the other side of the magnifier, 5-10cm away from it. Then move the finger slightly until it is large and clear (in focus). Students should be able to easily see their fingerprint. The key point is not to have either your eye, or the object being viewed, touching the magnifier.
Use the same method to look at specimens. Sometimes, instead of moving the specimen closer to the lens, it will be easier to move your eye and magnifer (keeping them apart) towards the specimen.
(See the Open Door Website at http://www.saburchill.com/lab/observations/observe01.html). The curved glass makes things look bigger. Ask students to make a drawing of their living thing, showing the details that they can now see with the magnifier that they could not see with the naked eye.

Proper use of stereo (dissecting) microscopes
Good for primaries and up.
Place an object on the stage, and while watching from the side, turn the focus knob to bring the lens as close to the object as possible without touching it. While looking through the ocular lenses on top, slowly focus up until the object is in focus. The stereo microscope magnifies 20 to 40 times, so bridges the gap between the visible and microscopic.

Proper use of transmission (compound) microscopes
Best for intermediate and older students.
The transmission microscope magnifies 40 to 400 times, and can be used to look at small details invisible to the naked eye. The light comes from underneath so the sample must be thin enough for light to pass through, and for the lens to move over. The sample can be mounted on a slide, or simply placed under the lens if it is flat enough to fit. To prepare a slide, place the specimen on the slide and add a small drop of water if necessary. If needed, arrange the specimen with a toothpick. Lay over the cover slip, by lowering from one side. First view the slide at the lowest power (40X), by starting with the objective lens at its lowest point and moving it upwards with the coarse focus knob, until the sample is in focus. Then the higher power lenses can be used in sequence, adjusting the focus using only the fine focus knob.

More detail on microscope use and specimen ideas:
http://www.saburchill.com/lab/observations/observe04.html
Levine, Shar and Johnstone, Leslie. 1996. The microscope book. Sterling Publishing Company

Further magnification in scanning electron microscope images
Show images of familiar living things magnified even further:
scanning electron microscope images at:
http://www.denniskunkel.com
Scharf, David. 1977. Magnifications. Publisher Schocken
Breger, Dee. 1995. Journeys in Microspace. Columbia University Press
or a google image search of "scanning electron microscope images"

You are made up of molecules that come in many different shapes, sizes and colors.
Explore your body, inside and outside, and find different kinds of molecules that make up you.

Some of your molecules are stiff and stack like bricks. They make hard structures like nails. Knock your head to find another hard molecule structure in you. What other hard molecule structures can you find on and in yourself?

Some of your molecules are springy. Springy molecules make elastic structures like your skin. Compare how elastic your skin is with other people's: pinch the skin on your knuckle, then see how long it takes to fall back into place.
In old people, the molecules are no longer as elastic as they used to be, so the skin takes longer to fall back. What other elastic molecule structures can you find on or in your body?

Your blood contains molecules that are red. You can see your red molecules by holding your fingers together and covering the end of the flashlight. Now find molecules on or in your body that are white. The mirror will help you find some of them. What about molecules that are brown? Do you have other colored molecules on or in your body?

Find molecule structures in you that are slimy and ones that are watery.

What other textures and colors can you find on yourself? They are all made of molecules.

Your molecules don't just make the textures and colors of your body. Your molecules also let you move, digest food or sing a song. Think of all the things your body can do. It is your molecules that do it!

Do you have a water filter at home, school or work? Lots of people drink filtered water. How does a filter work? Do an experiment to find out.

Take a scoop of grains from the water filter. This is a Brita filter, used in many home water filters. What do the filter grains look like?
Put a full scoop of the filter grains in a tube. Add blue dye to fill the tube halfway. Snap the tube closed.
Half fill a new tube with blue dye only. Close the tube. This is your standard. Later you will compare it to the tube containing filter grains.
Start the timer. Shake both tubes hard until the timer is done. Compare the two tubes.
What have the filter grains done to the dye? Where has the dye gone?

How do the filter grains work?
The dye molecules stick to the filter grains: Look at the round beads in your experiment. You may be able to see the blue dye stuck to them.

What happens in a home water filter?
In our home water filters, the filter grains remove unwanted atoms from tap water. Like the dye in your experiment, the atoms stick to the filter grains:
Calcium and magnesium are natural, harmless atoms in water, but they cause blockage in pipes.
Chlorine is added to drinking water to kill harmful bacteria. Some people don't like its taste.
Lead and copper leach from old pipes and are toxic in large amounts.
Although you could see the dye in your experiment, you can't see these atoms in tap water — they are too small and are not colored like the dye.

How much dye can the filter grains remove?
Open your tube containing filter grains and water. Use a dropper to suck the water from above the filter grains. Squirt the water into the trash. Add more dye to the grains. Start the timer and shake the tube again. Do the grains remove these dye molecules as well?

The filter grains in your experiment should have removed more dye molecules from the water. The round beads should have more blue dye stuck to them. In the same way, the filter grains in home water filters can be used over and over to remove unwanted atoms from the drinking water. Eventually the filter grains get full and cannot remove any more atoms. Then you need to replace the filter with a new one.

Experiment!
1. How many filter grains do you need to remove all the dye molecules? Find out by adding different amounts of grains to different tubes. Make sure you add the same amount of dye to each tube. Make sure you shake all the tubes for the same amount of time.
2. How long do you need to shake to remove all the dye? Try shaking different tubes for different times. Make sure the only thing that is different between the tubes is the shaking time — put the same amount of grains and dye in each tube.
3. Try your own experiments. Remember to change only one thing at a time, so you know why you see a difference between tubes.

Introduction:
What is it that makes some foods taste so sour?
Foods are sour when they have a high concentration of loose hydrogen atoms. (Atoms are tiny particles that make up us and everything we see around us. Atoms link together to make molecules.) Do an experiment to predict how sour some foods are without tasting them.

Indicator dye:
Add unknown liquids to wells of the tray.
Add the indicator dye, and look at the colour change. (With red cabbage dye, high concentration of hydrogen atoms turns the dye pink; low concentration of hydrogen atoms leaves it purple, and medium concentration of hydrogen atoms turns it pinky-purple. With commercial pHydrion pH 1-10 indicator dye, high concentration of loose hydrogen atoms turn the dye orange; medium concentration of hydrogen atoms turn the dye yellow; low concentration of hydrogen atoms turn the dye green. )

The liquid with a high concentration of loose hydrogen atoms is the most sour.
The food with a low concentration of loose hydrogen atoms is the least sour.
By looking at the color of the dye, predict which liquid is the least sour and most sour.
Taste the liquids to check. (Sometimes sugar is added to foods to offset the sour taste, so they may not taste as sour as predicted e.g. lemonade).

Baking soda bubbles:
Add a small scoop of baking soda to a well of the tray. Add water and mix together.
Drop a candy into the baking soda solution.
Bubbles will indicate that the candy has a sour coating, as the baking soda and the H atoms of the coating undergo a chemical reaction, making bubbles of carbon dioxide: HCO3 + H -> CO2 + H2O

Why foods taste sour:
In each case the loose hydrogen atoms interact with receptors on your tongue, and depending on their concentration your brain perceives the food as sour or not.