ingridscience

Write your note in baking soda solution.
Allow to dry.
The note will be barely visible (though not invisible).

Paint grape juice over the note to make it visible.
(The grape juice turns a different colour when covering the basic baking soda solution).

On the blank paper, ask students to draw around their hand(s). They will add a fingerprint to each of their fingers.

Use the pencil to scribble a dark patch on the corner of the paper.
Rub a finger tip in the pencil patch, pressing it down and rolling it around to make sure the entire finger tip gets coated in graphite.
Stick a piece of tape on the darkened finger tip, then peel it off. Stick the tape on the card over the appropriate finger tip.

Use an identification sheet to first determine whether each of the fingers have loops, arches or whorls. You may also find more complex patterns such as double loops or other combinations. This pattern is caused by ridges of skin. They stay in this pattern throughout your life, and even if you damage your finger they will grow back in the same pattern. Everyone, even identical twins, has a unique collection of fingerprint patterns.

Then look for minutiae - the places where the ridges start and stop and fork and merge. Challenge students to find a bifurcation, lake or hook.
Ask them to work with the magnifier and a fine-tipped sharpie to circle the minutiae that they find, just as a forensic scientist does.

Try these websites for images of fingerprint patterns and minutiae (or google search for "fingerprint patterns" or "fingerprint minutiae"):
http://www.forensicsciencesimplified.org/prints/principles.html
https://www.ijser.org/paper/Fingerprint-Minutiae-Extraction-and-Orienta…
https://globalwrong.files.wordpress.com/2012/02/galton-characteristics1…

Find the horse foods on the table.
Notice that they each provide different nutrients: fibre, protein, fat and vitamins
We need the same nutrients.
Match each human food with the horse food that provides the same nutrition.

Sitting in a circle version:
Sit at the carpet in a circle.
Hand each student a card with a living thing on it. Students hang it around their neck to display their living thing for everyone to see. Each student takes a turn to tell the class what living thing they are.
Tell students that energy comes into the living things from the sun, and ask which living things use the energy of the sun to stay alive. [Any plant]
For the chosen plant, start the yarn at that student: tape the end of the yarn to the carpet with duct tape in front of them. Ask this student to take off their living things label and place it on the duct tape in front of them.
Using students' ideas, unwind the yarn ball to a student that has a living thing that would eat the plant. Make a line of wool stretching between them, then tape the yarn strand to the floor in front of the new living thing.
Continue, connecting more living things together with yarn (it will criss-cross). Each time a student is added to the line of yarn, ask them to take off their label and place it on the duct tape, so you can see who has not been included yet.
Once you get to the top of the food chain (top predator, like cougar), you can move back down the food chain to something that is eaten by the predator. Move up and down the food chain as needed to connect everyone. At any point, you can connect to decomposers (slug, wood bug, mushroom) as they eat or grow out of a living thing after it dies. The order does not matter, but just connect all the living things to something else by who eats who.
A criss-crossing web of connections is made, forming a 'Food web'. (A food web is many connected food chains.)
For younger students, include each student once, then discuss how there are many more connections.
For older students that can sit longer, each living thing could be connected more than once.
Once the web is done, ask students to look at the web shape they have made with the yarn. This is why it is called a food web.
I also ask students to point to one other living thing that they are connected to in addition to the ones they are linked to by yarn. We have only made a part of the food web with the wool - there are many many other connections.
Discuss why biodiversity is important. If one living thing dies off, living things connected to it can find other things to eat because there are so many connections. With less biodiversity and fewer kinds of living things there are less back-ups in the system, so it is not as resilient.
For clean up, ask students to hand in their labels, then they should peel up the duct tape without moving the yarn. The yarn can then be wound back up backwards along its path without getting tangled.

This activity is inspired by: https://betterlesson.com/lesson/640194/the-food-web (see the Explore/Explain section).

Tabletop version:
Give student groups a stack of index cards with a living thing named on each.
Students lay the cards on a table, then use lengths of wool to connect the living things that eat each other.
Students could add their own living things to their food web.
Compare the food webs that each group made.

As a class, discuss how complicated a food web is, and how living things depend on each other. If one living thing is removed, through habitat change or human interference, other living things are affected.

What is this? Look at it with your magnifiers. (don't tell students what it is until they have looked at it and identified grass/seeds etc in it first).
Animal dung! Here is one whole piece of dung. You each have part of one of these.

All animals make waste, once they have extracted as much nutrition from their food as they can.

Use magnifiers to see what is in in dung. Here is the food they eat. How does it compare?

The [horse] does not digest much of the plants they eat. Plants are hard to digest. There is a lot of nutrition left in [horse] dung. So much that it is food for another animal.
What animals might use the nutrition in [horse] dung?
Worms, wood bugs (they eat rotting plants), birds (they eat seeds).

An animal's teeth is an adaptation for the food that it eats.

If herbivore jaws are available:
Look at the herbivore jaw bones and teeth. (Photos show lower jaws of herbivores.)
Herbivores have teeth that are adapted to smash up plants. Their incisors at the front of the jaw snip off the plant stems and leaves (these are often missing from a found jaw; only present in the sheep jaw in the photos). To grind the plants they use their molars, which have sharp ridges on the top and fit together perfectly to smash the plant cells open.
3D view of positioning teeth in a mouse jaw: https://www.youtube.com/watch?v=oLn70NiouS4

With a skull and associated jaws:
Insert the jaw bones in the skull and show how tightly the teeth fit together. Show how the jaw moves sideways to mash plants between the teeth.

If carnivore jaws are available:
Carnivores need sharp teeth to catch prey and rip meat. Canines are huge, and even on domestic animals they can be terrifying (show cat and dog photo). Incisors are tiny. The molars are sharp to shred meat.
Look at real carnivore skull to see teeth (e.g. I have cat skull with upper jaw including canines)

Look at human teeth:
We are omnivores - are jaws and teeth are adapted to eat both meat and plants.
Students use a mirror to find the different kinds of teeth in their mouth: incisors, canines, molars (use illustrations to show the different types)
Canines are there but small - between the two.
Incisors are more like herbivores though no where near as big.
Molars are between the two.
We are omnivores. (Same as bears and racoons.)

Look at the animal skulls or pictures. Ask students to notice the location of the eyes - whether they are on the front of the head or on the sides of the head.

Discuss how prey animals usually have eyes on the sides of their head, so that they are able to notice predators approaching from all directions. Predators often have eyes at the front of the head to enable better depth perception, which allows them to gauge more accurately how far away prey is, and to perceive prey that is trying to hide through camouflage.
The different eye arrangements are an adaptation for each animal's environment.

Optional: do activities to compare how eyes on the side of the head and the front of the head are useful:

Visual field test for the advantage of eyes on the side of the head:
Work with a partner to see how far behind us we can see: partner holds their finger behind your head, then slowly moves it around the side of your head. Tell them when you see the finger. Then switch over.
We cannot see far to the side - our visual field is about 200 degrees.
Herbivores are able to see much further to the side, with their eyes on the sides of their head - their visual field is 350 degrees. They can almost see behind their head.

Stereo test for the advantage of eyes at the front of the head:
Eyes at the front allow animals to see how far away something is - depth perception.
Try putting your fingers to the side, then slowly bring together to meet in front of you. Now try with one eye closed. (see notes)
For most of their visual field, animals with eyes at the sides of their head can only see with one eye. They may have binocular vision for a small part of their visual field, right in front of their face.