ingridscience

Students add a spoon of soil to a tube, then fill the tube 3/4 of the way up with water. Shake, then let it settle.
A few seconds of settling gives some instant generalized results, and settling over a longer time gives more detailed results.

Organic matter/dead living things float.
Tiny clay particles ('mineral' component) are suspended in the water column.
Heavier sand and gravel particles ('mineral' components) sink to the bottom of the tube or jar.

Discuss the relative amounts of different components in the different soil types.
For the soil types we tested:
forest soil is almost all organic
beach soil is a mix of organic and mineral components although by volume the mineral component is larger
garden soil is a mix of organic and mineral components, with a lot of tiny mineral particles suspended in the water.

If this activity is done in a larger mason or jam jar, and left to settle over days, the mineral layers of clay, sand and gravel separate out more clearly, and their relative heights can be measured for an accurate breakdown of the mineral (rock) components of the soil.
See the image at https://images.squarespace-cdn.com/content/v1/5cdecce138275f0001d2fd9b/…
and "Soil texture jar test' at https://bcfarmsandfood.com/three-simple-ways-test-soil/

Students work in groups, ideally 4 students or less, each group with a set of sieves, and one or more soil samples.

If using one sieve, the students can separate the large and small components:
Scoop a small amount of soil into the sieve. Shake the sieve over a clean tray so that the small components fall into the tray and the large components remain in the sieve. The separated components make it easier to study what the soil is made up of.

If using a series of different mesh sizes the students can do several separations of components:
Dump the soil onto the large mesh sieve laid over a tray. Shake the sieve and tray simultaneously until soil stops falling through the sieve. Transfer the large soil components trapped by the sieve onto a sheet of white paper. Dump the contents of the tray onto the next smallest sieve size (sitting on a tray), repeat the shaking, transfer the trapped components to a new white sheet of paper. Repeat for the smallest sieve size. Transfer the soil remaining in the tray after the third and final sieve to its own sheet of paper.

Clean the sieves then repeat the soil component separation for the other soil types.
For each of the soil types, lay the separated components side by side to show the change in the soil components between soil types and from large to small.

Play-Debrief-Replay format:
This activity was run in a free-experimentation lesson using two soil types and one sieve size. Students were allowed to explore as they liked (though were requested to keep the soil types separate and in the trays). They took notes on what they found. We gathered as a class and heard what the students had found. Then students chose a particular aspect of the activity that they wanted to pursue further, then returned to the materials to investigate this further, partnered with students that had a similar interest.

Thank you Exploratorium for this activity: https://tinkering.exploratorium.edu/sites/default/files/Instructions/sc… and https://tinkering.exploratorium.edu/scribbling-machines

For drawing jiggly lines: (photos 1-4)
Tape some pieces of popsicle stick together, or cut a piece of glue stick. Popsicle sticks need to be taped firmly after pushing the motor shaft through them. For the glue stick, use a skewer to make a hole in it, then push it onto the shaft. Other weights can be used too, but make sure they are attached firmly. The lop-sided added weight will "offset" the motor and make it shake.
Tape the offset motor on a top edge of the plastic tub, so that when it spins the added weight does not hit the tub.
Tape the battery to the top of the tub, and attach the motor wires so that one of them is easily removable with a flap of tape (see close up photo).
Tape three marker pens as legs to the tub.
Start the motor and place the scribbling machine on the paper.

For drawing smooth circles: (photos 5-7)
Tape the motor to the plastic tub so that its shaft is pointing down, making one leg.
Tape two marker pens around the tub to make two other legs.
Tape the battery to the top of the tub, then connect it to the motor with masking tape.
Start the motor and place the circle-drawing machine on the paper. The marker pens may need to be moved around a bit until it is stable.

Students find the flowers in the images, count the number of petals on several of the flowers (e.g. 5), and record the numbers.
Students can add their numbers to a class chart, to see how there is a common number of petals for each type of flower, but there is also some variability.

While the popcorn is popping, talk about what is happening to make this food:

Each kernel has some water in it. (Corn that is used for popcorn has just the right amount of water: 13.5%.) As the hot oil heats up the kernal, the water inside it evaporates to form a gas (water vapour). The shell is strong and watertight so the gas cannot escape.
As the heat increases further, the water vapour molecules move around more and more vigorously, exerting more and more pressure on the inside of the shell. Eventually the pressure inside the kernel is great enough to burst the shell. (This happens at about 180 centigrade, when the pressure inside is 135psi.)
As the shell bursts the pressure suddenly drops again. This causes the water vapour to expand which makes the starch and proteins inside the kernel expand into an airy foam.

Corn kernel molecules and popping explanation link: https://www.acs.org/content/dam/acsorg/education/whatischemistry/advent….

Students can inspect the kernels as they eat them, and see that the shell turns inside out from the force of the explosion.

If students have done some acting out the sates of matter already, they can do skits in small groups on what is happening inside the popcorn to make it pop - each student can be a water molecule, or the kernel shell, or a narrator. Gather to view each others' skits.
(Students can prepare their skits as the popcorn pops if it takes a while.)

Show students slow motion videos of popcorn kernel popping (maybe while they eat their popcorn):
https://www.youtube.com/watch?v=CXDstfD9eJ0
https://www.youtube.com/watch?v=NCSr18vtjeo

more popcorn info at: https://www.popcorn.org/Facts-Fun/What-Makes-Popcorn-Pop
Make popcorn with a microwave and paper bag; https://www.allrecipes.com/recipe/87305/microwave-popcorn/

For a lesson on heat:
Popcorn can be made as part of a lesson on heat. Students brainstorm whether the popcorn is being popped as a result of conduction, convection, radiation or all of them.

For a lesson on seeds:
Compare popcorn kernels with the kernels on a corn cob.

Teach students how to make a basic paper airplane. If they know already, let them fold their way and start testing immediately. Make sure students make the creases tight and neat as they can.

(Plane design ideas with step by step instructions at many websites, including https://www.exploratorium.edu/exploring/paper/airplanes.html and https://icdn.kiwico.com/landing/at-home/2020_04-Kids-at-home-Printables…)

Forces on an airplane
Ask students to think about the forces on their planes as they fly them. Students can alter their models now if they want, but for now, the emphasis should be on watching them fly and thinking about the forces involved.

After a while, stop the flying action, gather as a group and discuss what forces they think keep the plane in the air. Introduce terms and round out the concepts as appropriate for the grade level:
1. Thrust is the forward force on an airplane. Your arm muscles throwing the paper airplane generate initial thrust which send the paper airplane forward. (In a real airplane, thrust is from a propellor or jet engine and is continually acting as the plane flies.)
2. Drag is the force that slows the plane down as it pushes against the air it is moving through. It is a kind of friction and is also called called air resistance. It acts in the opposite direction from thrust. Thrust must be equal to or greater than drag for a plane to move forward, hence your paper airplane slows down as the energy from the initial thrust is used up. The more streamlined an object is, the less drag it has. (Airliners retract their landing gear between take off and landing to reduce drag on the landing gear which would otherwise rip it off.)
3. Gravity is the force pulling the plane downwards. It acts on the mass of the plane, giving it weight.
4. Lift is the force that pushes the airplane up, acting in the opposite direction of gravity. Lift is produced by the wings and the air flowing around them (either the wing or the air must be moving - they just need to move relative to each other).
The tilt of the airplane and the angle of the wing means that air flowing off the wing flows downwards. This downwards force pushes back up against the wing, and lifts the wing (because of Newton's 3rd Law of action and reaction). (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 a plane can fly upside down.)

Depending on the strength of each of these forces, the plane will fly forwards, downwards, upwards or stop.

As an aside, drag and lift can be felt with a hand out of a 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 flat hand straight out of the window, then slowly tip it so the front edge is tipped up a bit, the air is directed downwards and pushes your hand up. The effect is quite dramatic and nicely demonstrates action and reaction.

Continuing the lesson, ask students how they might make their plane go further. Ideas following.
More thrust by throwing more strongly (they are probably doing this anyway).
More streamlined to reduce drag (change how it is folded so it has a narrower front),.
More lift by changing the angle of attack (point it upwards to start). To tip the nose of the airplane upwards during flight (and keep the angle of attack optimal), bend up the back of the wings a little (see photo). A little bend goes a long way. Air flowing off this bend will push the back of the airplane down, which will lift the nose.
If the nose rises upwards and then the plane drops, the plane is stalling. Bend the back of the wing downwards, to make more air flow downwards off the back of the wing and lift it, so tipping the nose downwards - now the nose does not rise so fast and the plane will not stall. Keep your adjustments small. Real airplanes use flaps to keep the plane level during flight and after landing.
You may also want to discuss adding other folds, such as winglets, to their plane. Winglets are additional upwards folds on the end of the wing, and reduce a vortex of air that pushes the wing down.
Flaps cut into the back edge of the wing can also increase lift, or be bent in opposite directions to make the plane spin.

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

Airplanes modelling how birds change direction
Fly an airplane to see how long it stays aloft.
Then bend up the back of the wings a little (see photo) - it should stay aloft a little longer.
Then bend the back of the wings down - the plane should dive to the ground soon after launch.
Try bending one up and one down (see photo) - at least one of the planes will roll as it flies.
Birds move their feathers on their wings, to change the direction of their flight.

Airplanes modelling bird wing 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.

Newton's Laws in a paper airplane
First Law - objects will stay stopped or in constant motion until a force acts on them (the force of your hand makes the plane go forward, the force of gravity points it to the ground)
Second Law - F=ma: for a constant force a smaller mass will accelerate more than a larger mass; a greater force will make the same mass accelerate more (a greater push from your hand will make the plane go further)
Third Law - for every action there is an equal and opposite reaction; when an object pushes on another it gets pushed back with equal force (your hand pushes on the plane and the plane pushes back on your hand, sending it forwards)