ingridscience

Show and fly a paper airplane. We will make one.
It flies because of Newton’s Laws.
List Newton's Laws, while adding the forces to a drawing of the plane next to the list (see photo):

Newton’s 1st Law Objects stay stopped or in constant motion until a force acts on them (Thrust, drag, gravity)
(A force might make an object start, or stop, or change direction)
Newton’s 2nd Law F=ma (More or less thrust)
A bigger force will make the same mass accelerate more
To move a bigger mass, you will need a larger force move it the same
With the same force, a smaller mass will accelerate more than a larger mass
Newton’s 3rd Law For every action there is an equal and opposite reaction (Lift)
(When an object pushes on another it gets pushed back with equal force)

Expand on the Forces, as needed:
Thrust:
Makes the plane move forwards. Your arm muscles give it thrust; a harder throw gives it more thrust.
Real airplane: the thrust is from a propellor or jet engine, and is continually acting as the plane flies.
Drag / air resistance:
The force that slows a plane down as it pushes against the air as it moves. It is a kind of friction. It acts in the opposite direction from thrust.
Thrust must be greater than drag for a plane to go forwards.
Streamlined objects have less drag (there are more streamlined paper airplane designs). Airliners retract landing gear in flight so it is not ripped off by air resistance.
Gravity:
The force pulling a plane downwards.
(It acts on the mass of the plane, giving it weight.)
Lift:
Pushes the airplane up, acting in the opposite direction of gravity.
Lift is produced by the wings and the air flowing off them. The tilt of the airplane (the 'angle of attack' and the angle of the wing shape (where relevent) makes air flow off the wing downwards (the 'action' of Newton's 3rd Law). This downwards force pushes back against the wing ('reaction' of Newton's 3rd), and pushes upwards on the wing.
Either the wing or the air must be moving - they just need to move relative to each other, for lift to be generated.
(The Bernoulli effect has previously been used to explain lift, but is now known to be insignificant, or even incorrect - it doesn't explain how some planes can fly upside down.)
As an aside, drag and lift can be felt effectively with a hand out of a moving car window:
Holding your palm flat against the wind you can feel the air pushing against it: drag, or air resistance. If you make a fist, your hand is smaller and there should be less drag on it.
If you hold your horizontally flat hand straight out of the window, then slowly rotate your wrist it so the front edge of your hand tips up a bit, the air is directed downwards and pushes your hand up. The effect is quite dramatic as it kicks in, and nicely demonstrates action and reaction.

Students make their paper airplanes, with assistance if needed. Make sure students make the creases accurate and tight (run a nail over folds).
If they want to make their own, keep it simple - no flaps yet.
Fly it. Get a consistent thrust. Ask students to think about the forces on their planes as they fly them.
Note you get more Lift by changing the angle of attack (point it upwards to start).

Then step through these changes as a class (or demonstrate at the start if there is to be more free exploration):
1. BEND UP the outside back of the wings (see photo), by 45 degrees (not a right angle). Air flowing off those bends upwards (action) pushes the back of the plane down (reaction), lifting the nose of the plane. This should keep the plane aloft for longer.
If the nose of students' planes rises upwards too steeply, the plane will suddenly drop: the plane is 'stalling'. Make the bends a smaller angle.
2. BEND DOWN the back of the wings to make more air flow downwards off the back of the plane (action), which pushes the back of the plane up (reaction), which tips the nose downwards. Students' paper airplane might nose-dive with this modification!
3. SPIN the plane by bending the back of one wing down, and the other up.
Newton's 3rd Law of Action and Reaction explains how all these flap changes effects the flight of the paper airplane.
In real planes, some wings also have 'winglets', which are upwards folds on the wing sides, to reduce a vortex of air that pushes the wing down.
4. Students may want to try cutting and folding flaps in their planes, to see how they affect the flight.

Encourage students to share designs, and allow more time for testing.
They can optionally measure and record how far their plane goes. Optionally generate a class graph of the distances achieved, and discuss factors that might increase flying distance.

Airplanes, Cars and Birds use Newton’s Laws (photos/video):
Real airplanes: use flaps to keep the plane level during flight and after landing (see photos).
F1 cars: show DRS system. For going around corners fast, they have no DRS, as the air flowing off the rear wing pushes the back of the car down, keeping it from sliding off the track (Newton's Third Law). On long straight stretches they use DRS ('drag reduction system’): reduces the downforce so go faster.
Birds: glide for the same reason that paper airplanes fly, using lift.
They also push air to take off and manoeuvre. Watch slow motion of birds flying https://www.youtube.com/watch?v=qThIyj1mLfs.
Air seems like nothing to us as we are heavy. When a light bird pushes against air particles, they are small enough that the push makes them move.
Just as adjusting your plane changes the flight, birds move their feathers (with muscles) to change their flight path.
Birds adjust their wing and tail feathers to change their flight direction. Depending on the wing shape, and which way they push, they make amazing manouvers in the air.
Note: the shape of birds’ wings are different on the downstroke and the upstroke.

Optional alternative focus:
Airplanes modelling wide and streamlined bird shapes
Build differently-shaped airplanes, to model how some birds have wide wings for gliding, and others have swept back wings for fast flying. See this link for designs: https://www.audubon.org/news/these-paper-airplanes-fly-birds See the paper raptor designs from this link: http://idahoptv.org/sciencetrek/topics/birds_of_prey/activity3.cfm
Some birds of prey have swept back wings, so that they can dive at high speeds and catch other birds (e.g. peregrine falcon).
Some birds have long, wide wings to help them glide and look for prey e.g. hawks, eagles. They can open their wing feathers at the ends to keep the airflow around the wingtips smooth and to prevent stalling at low speeds.
Some birds have short broad wings and long tails to allow tight manoeuvring and quick takeoffs e.g. woodland hawks. However, they need to flap a lot.

Before the lesson, find some good habitats for decomposers e.g.under logs and dead leaves, then take the students to these sites.

Students hunt for anything living in the soil. As they look more closely they will notice smaller and smaller animals. e.g. worms, wood bugs, slugs, snails. Also fungi and bacteria.

Discuss with the students what these animals eat, and that many of them have an important role as decomposers - living things that eat dead plant and animal matter. They break down living things into simple molecules that can be then used by plants (carbon compounds to CO2; nitrogen cpds to nitrite, nitrate and N2; phosphorus cpds to phosphate).
Decomposers often prefer it moist, dark and damp, where the rotting process is fastest.

Optional: study the animals more closely with magnifiers on site.
Optional: collect a few animals in soil to take back to the classroom, study more closely and make a food web.
Optional: collect worms or wood bugs to keep in a habitat in the classroom. Or release worms or wood bugs that have been in the classroom for a while.

Return any animals that do not have a habitat in the classroom to their collection site.

This is the last activity of the Honey Mystery.

Students compare the "fingerprints" of the left paw of each cat (as the investigators determined that someone picked up the honey jar with their left hand). See the worksheet.
Identify whether each print is an arch, loop or whorl.

Then look at the prints found on the honey jar (this can be given as a separate piece of paper to stick onto the worksheet).
identify which cat made the prints on the jar.

For our case, it was the black cat that stole the honey.

Please note that in a class of students it is likely that one of them is at least partially colourblind (1 in 12 males are colourblind). As this is an activity distinguishing colours, these students will not be able to tell some colours apart and perceive some colours differently, although the activity will be no less interesting for them. The common red/green colour blindness means reds and greens (or colours containing reds and greens such as browns) look similar. More information at colourblindawareness.org and colorblindguide.com/post/the-advantage-of-being-colorblind.

Before the lesson, write the note using one of the black pens. Example of what it can read: "What you seek is buried under the old cedar at the back of the house". Something more applicable to the classroom or school building would be better.

In the lesson, read the note to the students, and show them the black pens that might have written the note, and that they will use chromatography to figure out which one. Demonstrate the steps below, before allowing them to proceed.

Prepare chromatography strips for the black pens:
Cut out filter paper, using the template to make the correct size. Draw a pencil line across the paper, where indicated on the template (see 1st photo).
With each black pen make a line across the strip of the filter paper, over the pencil line.

Prepare chromatography strip for the ink on the note:
Cut off a small piece of the note with a word on it, lay it word-side down on a filter paper strip, at the same level as the line on the template, and use a paperclip to attach them together. (2nd photo.)

Run the chromatograms:
Clip the top of the filter paper strips with the small binder clips (for all the black candidate pens, and for the note). Then thread the coffee stir stick through the binder clip arms and lay the sticks across the top of the tub. The filter paper should dip into the water, but the black lines and the piece of note are above the water line. Allow the chromatograms of the three candidate pens to run (3rd photo). Wait three our four minutes until the colours have separated up the filter paper to within 1cm from the binder clip.
Although the chromatogram with the note is not as distinct as the chromatograms from the black lines, the colours should still be distinguishable, so that the pen that wrote the note can be identified (see 4th photo comparing the chromatogram from a line and from a note).

Many black pens have a different chromatography pattern (see 5th image). Note that marker brands change their ink composition now and again (e.g. crayola now has more ink colours in some of their black markers).

How does chromatography work?
The coloured dye molecules in the ink of the pen are attracted to both the water that it is in, but also the surface of the filter paper. Each different colour is attracted to the water or the filter paper to different extents. As the water moves up, the dye molecules that are most attracted to the water will move along fast with it. If the dye molecules are mostly attracted to the paper, they will get stuck to the paper and not move along with the water at all. Most colours are attracted to both the water and the paper, so will travel with the water for a while, then stick to the paper for a while. Depending on the relative attraction of a dye to the water and the paper, a colour will travel at its own rate. The differing rates of travel separate out the colours.

Students view human and animal hairs with magnifiers and ideally a microscope. They can tape them to a worksheet, piece of paper or microscope slide to make viewing easier. They should notice different colours and widths. Under the transmission microscope the pattern of scales on the surface of the hair will also vary.

For a lesson on animal hair function:
Look at the different thicknesses of hair and discuss their purpose. Dense, fine underfur (for warmth) and the long, coarse guard hairs (for protection against the weather and dirt, to raise when confronting other animals.

For a lesson on forensics:
Discuss how hairs are quite different from each other. They can often be used to determine the race of the person they came from, and also whether the hair was dyed. Hair also contains chemicals that have been ingested, so can be tested for drugs or other chemicals.
Students can have an array of hairs in little baggies, and guess their source e.g. cat hair may have identifiable colours distinct from human hair.

Optional: Give students other kinds of "trace evidence" each in their own baggie, for students to try and identify, to mimic a crime scene investigation e.g. paint flakes, wood splinter, carpet hairs.

Forensic scientists may find hair with a root attached - you can pull out a hair from your head forcibly to see the root (a tiny white blob). The root contains hair cells, which can be used to extract DNA and identify a person involved in a crime.

Background: There has been a crime among the stuffed animals. Pooh's honey was stolen while he was sleeping. The empty jar was found near him. The investigators collected hair samples from the honey jar and put them in baggies.

Each student is given a worksheet (see attachment), and asked to record the hair colours of each stuffed animal that was found in the vicinity of the crime scene.

Each student is given two baggies, containing hair samples 1 and 2 respectively from the crime scene.
Students hold the samples against white paper and black paper and use a magnifier to determine the colour of each hair. They will need to look closely as there was not much hair recovered from the crime scene.
They tape the baggie next to the recorded hair colour.

By matching the hair samples from the crime scene with the hair colours of each stuffie, students figure out which of the stuffies are still suspects. (The black and brown bear, and also both cats as the brown hair could have been Pooh's.)