ingridscience

Bend the end of the wire into a triangle, and tape to the desk. Bend the long straight end of the wire upwards. This is the stand for the spinner.
Cut the square piece of card stock into a circle (optionally using a compass to draw a circle on the card first). It does not have to be exactly circular, but make as large as possible.
Cut from the edge of the circle partways toward the centre, to make blades (telling them half way is fine if students might cut too far). Six or eight blades seem to work best.
Use a straight edge (ruler or book) to fold half of each blade partly upwards (see photo). Or fold by hand but make sure the crease is tight.
Make a small hole in the centre of the circle with the scissors (or pre-punch a central hole in each piece of card for students) then push the tube/cap through.
With the blades pointing down (may need to reverse the direction of the tube/cap), place the pinwheel on the end of the wire. Make sure the wire is not touching the edge of the tube/cap except at the very tip (keep friction to a minimum).
Use two small pieces of modelling clay to secure the candles on the desk under the pinwheel, making sure there is some space between the pin wheel and the candle (so the paper does not catch fire). One candle can work too if everything else is optimal, but starting with two gives the best chance of pinwheels working.
An adult lights the candle. Wait for the pinwheel to start turning. Do not leave unattended.

If a pinwheel does not turn, here are some troubleshooting ideas:
Make sure the wire tip is only touching the very end of the tube/cap. Any rubbing of the wire along the length of the tube/cap will create too much friction for the wheel to turn. Bend the wire so that it is perfectly vertical inside the tube/cap and only touching at the very tip throughout an entire turn of the pinwheel.
Make sure the unfolded part of the blades of the pinwheel are not sagging, and bend upwards until horizontal if they are. (The paper curls down a little from the initial heat of the candle.)
Adjust the angles of the folds in the blades, so that they are not too vertical and not too horizontal. (The angle with the incoming rising heat is important.)
If students are walking around the classroom a lot, the air currents they create will disturb the heat convection currents that make their pinwheel turn. Keep them seated as much as possible so that the candle flames are directly upwards.

Once students have made a candle pinwheel that works from these instructions, and they understand the need for the angled blades, they can make shapes of their own to test and troubleshoot.
As long as they have a large enough surface area of sloping blades and the card is balanced on the wire, it should turn. One student group made a heart shape that was a little unbalanced, but by moving the place that the tube was pushed through, and with with the help of my lighter at a critical point in its rotation, I could add enough heat to push it past its sticking point.

How it works:
Air heated by the candle flame flows upwards by convection.
The hot air rises and meets a sloping blade of the pinwheel, and pushes against it (the air molecules bang into the blades). Because of the slope of the blade, the blades are pushed sideways and because they are part of a wheel, they rotate.

Once everyone's pinwheels are turning, turn out the classroom lights for a beautiful scene.
To consolidate how it works, students can draw their pinwheel, showing how the heated air rises and hits the blades (blow out candles first).

Additional experimentation for students to try out:
Does it make a difference which direction the blades are folded relative to the incoming convection heat? i.e. can they angle up instead of down?
Does it make a difference how many blades there are?
Try a completely different shape: a flower or a starburst with many blades.

Good activity to follow this: candle chemistry.

Pinwheel shape idea from https://www.youtube.com/watch?v=_TRKsKMuYZ8

Set up the gravity well and add a golf ball and about 20 marbles to it.

Tell the students that the golf ball represents the Earth, and the marbles represent the ocean water.
The gravity of Earth (modelled by the well in the fabric) attracts the water and holds it in place, just as gravity pulls on us and stops us from floating away.
We can model the Moon orbiting the Earth by pushing our hand down into the fabric to make a second well in the fabric, and circling it around the "Earth". As our hand moves, the marbles roll slightly towards the "Moon" and follow it as it orbits.
(Note that it is tricky for students to make the right amount of gravity (pushing into the fabric the right amount) and orbiting at the right speed (moving the hand in a circle around the golf ball), to make the water follow the "Moon" without leaving "Earth". Demonstrate how to make it work.)

The real Moon's gravity also pulls on the oceans, not so much that the water leaves Earth, but enough to make it follow the Moon in its orbit. The water nearest to the Moon will bulge out.
Tides on Earth are a result of this gravitational attraction of the Moon on the Earth's oceans, with additional factors:
The Moon causes the water to bulge out on the side nearest it. Because of the difference in the gravitational pull of the Moon on the near and far side of the Earth, water is also pulled out on the opposite side from the Moon.
The Earth rotates under the tidal bulges, so each point on earth moves through two high tides in one day.
The sun also pulls on ocean water. When the sun and the moon are lined up (new or full moon) the tides are higher (called spring tides). This happens twice a month. At half moon, the sun and moon are pulling water in different directions, so the tides are lower (neap tides).
The land masses and the varying ocean depths mean that the tides are on a more complex cycle than this (https://oceanservice.noaa.gov/facts/moon-tide.html), but they all originate with the pull of the moon on water.

Animation of the tides:
https://oceanservice.noaa.gov/education/tutorial_tides/media/supp_tide0…
https://oceanservice.noaa.gov/facts/springtide.html
Image at https://www.ck12.org/earth-science/Tides/lesson/Tides-HS-ES/

Another interesting phenomenon occurs with the gravity well where if the hand is moved fast the marbles will fly out in a line following the hand. This is a model of the Roche limit, how a satellite breaks up when it gets to close to a planet. See more on page 23 of https://www.spsnational.org/sites/default/files/files/programs/2012/soc…

Also note that students will want to explore more with the marbles, picking them up to make them orbit - follow this activity by using the gravity well more to explore orbit shapes and speeds.

Try digging the sand and grabbing the cloth with the tools.
Which one is best for digging? [the spoon] Which one is best for grabbing? [the fork]
Look at pictures of animal feet that dig (mole) and grab (woodpecker, cougar, osprey) or both (raccoon). Check out the wide shape for digging and the sharp claws for grabbing.

Students choose a glove and fold down their fingers, the same ones as the glove, then put their hand into the glove.
With the fingers that remain outstretched, try and pick up a marble. (Make sure that younger students do not use their fingers curled inside the glove to help manipulate.)
Which gloves are easiest to use and which the hardest?

Discussion: usually it is easier to pick up objects when the thumb is involved. The thumb sticks out in another direction from the fingers (it is opposable), so grabs the object from another side, helping pick it up.

Other animals with opposable digits:
Some other animals have opposable digits on their feet and are also dextrous: gorilla, chimp (and other great apes), baboons (and other Old World Monkeys) gibbons, giant pandas and opossums.
Birds also have one digit facing backwards on their feet, making them good at gripping branches.

Raccoons do not have opposable thumbs, but are able to fold their fingers down into their palms, which helps them with dexterity.

Use a saw to make a notch on either side of both jumbo popsicle sticks, about 2cm from one end.

Stack up 8 regular popsicles sticks. Insert the notched-end of one jumbo popsicle stick between the bottom two of the stack. Wrap the stack of 8 tightly with elastic bands on each side.
Lay the second jumbo popsicle stick over the top of the stack, with its notched end aligned with the jumbo stick tied into the stack. Wrap an elastic band around both jumbo sticks, making sure that it rests in the notches.

Make tin foil balls to fire with the catapult. They will go about 1m into the air.

Discuss the pushes and pulls: push down on the catapult, then as you let go it pushes the ammo into the air. The ammo falls back down as gravity pulls on it.

Print out the template double sided, then cut into three strips. Fold each strip in half into a two page booklet, with a bird on the outside and inside.
Ask students to draw one wing up on one of the birds in their booklet, and one wing down on the other bird.
Roll the top page around the pencil, starting from the outside edge and rolling towards the fold of the booklet.

To make the bird flap, push the pencil inside the rolled page, then move the pencil back and forth rapidly to reveal and hide the top page.
Our brain links the rapidly switching images so that they look like one bird flapping its wings.

Distribute a small piece of modelling clay to each student. Tell them that this is the body of the animal they will be building.
Ask students to shape the body, then add the fins and wings, to make a fish or a bird. They can copy the fin and wing locations of animals in pictures, or make up their own animal.
Fins and wings are often similar shapes, so many of the pieces can be used as fins or wings.
Encourage students to pair the wings or fins, as they are on real animals, and to angle them correctly to make their model look more real. Students will also enjoy making their own fantastic animal creations with assemblies of fins and wings.

Ask students to watch the fish closely, and count all their fins. They have more than expected - there are often several underneath as well as the more obvious tail and dorsal fins.
If students are to draw the fish, it will help them find all the fins.

Notice how the fish, with just a twitch of one fin or other, is able to manoeuvre precisely.