ingridscience

Students place coins on the material, then move a magnet around underneath, to see if it can move the coin through the material.
Encourage them to try different materials and thicknesses by stacking materials.
Using books, they can have fun adding the coin to an illustration.

The magnet will pull the coin through thinner materials, but not thicker, irrespective of the kind of material.
Steel and other iron-containing materials will attract the magnet themselves and affect the results - do not include iron-containing materials with younger students.

This activity shows that magnetic force can act through materials and can act at a distance (the magnet does not have to be touching the coin to attract it).

I have run this activity after introducing levers to students: I show the lever bar, the fulcrum and the load. Show how they can change the position of the fulcrum. Then the students free play with the materials, centred around the lever concept.

Encourage them to make chains of levers or see saws.

This activity is fairly chaotic. For a more structured exploration on the effect of fulcrum position in levers see lever experimentation: projecting a ball or Balance point on a stick or ruler.

Make the stars:
Cut lengths of black thread, one for each star in the constellation. Make them all the same length, a few cm longer than the longest length needed.
Tape a flat piece of foil to a thread end, then scrunch into a round ball (representing the stars).
Make enough of these for the number of stars.

Cover the cardboard circle with black paper.
Lay the constellation template over the centre of the black paper circle, and tape with removable tape (e.g painter's tape, or use masking tape lightly).
Poke holes through the cardboard corresponding with the pattern of stars with the stick, then remove the constellation template.

Choose which star to hang first, then check it’s position on the cardboard by looking at the constellation template, and check its thread length on the table of thread lengths. Push the free end of the thread (the other end from the star) through the correct hole in the cardboard, using the skewer to push it through. Pull the thread through the hole until the star is hanging the correct length below the black side of the cardboard, then tape the excess thread on the backside (non-black) of the cardboard to secure it. Lastly, lightly tape the hanging thread and star to the black cardboard so that it does not get tangled with other stars as they are hung, but so that the tape can be removed once all the stars are hung. Repeat threading, measuring and hanging for each of the stars.

Once all the stars are threaded through the cardboard, remove the temporary tape to release them into hanging position, then hang the model from the ceiling or a wire with string, making the string as inconspicuous as possible from below.

If the cardboard is not stiff enough to stay flat on its own, use a smaller square of double thickness cardboard, make a hole in each corner of this, loop string through so it can hang level. Tape or staple the round cardboard, with stars hanging below it, to the bottom of this stiffer cardboard.

Stand, sit, or lie directly under the constellation so that it looks as we see it from earth. The black thread should be invisible against the black cardboard, and the shiny stars should appear to float.
Move to the side, and notice how the stars that appeared to be in one plane from below are infact at very different distances from "earth".
Watch how the constellation rapidly changes shape as you move around the room - this is equivalent to you moving to different places in the galaxy.

Optional:
Find new patterns in the stars as you move, and give them names.

See this article for an image of the Big Dipper, Little Dipper and Pole Star in the night sky: https://owlcation.com/stem/AstronomyBeginnersGuideStars-Greensleeves Several of the stars in the Big Dipper are 80 light years away.
This website shows what is in your night sky: https://www.timeanddate.com/astronomy/night/

This activity has been run using the Play-Debrief-Replay model of science education described in "The New Teaching Elementary Science" book (see resource).

Students try mixing different combinations of solids and liquids and the teacher records the new textures they find.
At some point, optional with age, encourage pair-wise mixing so that students can determine which substances produce the result seen.
Students can optionally write down their discoveries as they make them, so that they can refer to them when the group is brought together to discuss findings (though with young students papers end up messy, and might take away the time to experimentally play).

Some expected outcomes and terminology for older students:
Absorb: some solids will soak up liquids
Dissolving: some solids will “disappear” into the liquid as they dissolve in it. Solute/solvent.
Suspension: some solids will disperse in a liquid but not dissolve, to make a suspension.
Solutions and suspensions are both kinds of mixtures.
Chemical reaction: some solids and liquids will react together to make new things (gas bubbles appear when baking soda and vinegar are mixed).

Discussion with lower primary students:
The various mixtures make different textures: goopy, sloppy, slimy etc. Some mixtures make bubbles or foam (depending on starting materials).
Materials that we use every day have their own useful properties. Goopy mixtures can make glues. Some mixtures harden like concrete.
Mixtures that make bubbles of gas can be used for many things, for example, to make interesting candies (pop rocks), or even can be used to send rockets to space (the gas pushes out of the back to make the rocket go up).

How do we know if there has been a chemical changes?
A chemical reaction produces a change in the molecules. Clue that a chemical change has happened: a new gas or other new state of matter, or a new colour or smell. But often, more must be known about the molecules to tell for sure.

This activity can be run as free play and/or a more organized game.

Free play:
Students are given the coins and asked to flick one across the table to hit another. They can experiment with changing the size of the coin that they flick and the coin that is hit, making a line of coins and flicking the end one, flicking the bottom coin of a stack, and other activities that they will invent.

Try flicking the coins across different surfaces (carpet, smooth floor, sand paper) and compare which slows down the coin most and which slows it down least i.e. which has most friction and which has least friction.

Coin game:
Two students sit opposite each other and make a goal with their index and little finger of one hand over the edge of the table. Each student starts with the same number of coins. Score goals by flicking coins into the opponent’s goal.
Rules:
In every play a coin must hit another, and for a goal to count.
Coin is out of play when it it flicked off the table.
Final score when all the coins are in goals or off the table.
While the students play, ask them to notice how energy is transferred from one coin to another. At the end of the games, bring up the same concepts as in the free play Debrief above.

Games that involve similar transfer of energy: curling, billiards, boules.

Discussion of the forces and energy transfer:
The force of the finger hitting the coin makes it move.
The force of one coin hitting another makes the second coin move. As one coin hits another, energy is transferred from the first coin to the second coin, so that the first coin can move and the second coin stops moving. Depending on the relative sizes of the coins the second coin will move far or less far. If the flicked coin is small enough and the second coin large enough, the flicked coin may bounce off.

Coins stop moving along the table, even if they do not hit another coin, as some energy is lost as heat from friction between the coin and the tabletop, and some is dissipated as sounds waves.

For older students the coins act according to Newton’s Laws of Motion:
First Law: Any object will stay still, or continue to move in a straight line, unless an external force acts on it (e.g. finger hitting coin, coin hitting another coin).
Second Law: Larger force or a larger object will alter the speed of motion of an object (flicking harder, or using different-sized coins will alter how far the coin moves).
Third Law: An object will have an equal and opposite reaction to the force applied to it (the coin pushes back on the finger when it moves forward).

This activity has been run in several ways:

Free experimentation with the collection of materials, asking students to explore floating and sinking. See the resource for the Play-Debrief-Replay method of teaching free play.

Challenge 1:
Make a flat piece of foil sink or float. Make a crumpled piece of foil sink or float (air gets trapped in crumpled foil unless it is crumpled under water, or pressed together tightly). Shape a piece of modelling clay so that it floats.
After making boat shapes from foil or modelling clay, add cargo of marbles/coins to see how much it can carry before sinking. In each case ask students to explain what is happening in terms of weight/density/displacement/buoyancy.

Challenge 1 as an activity on boats and how they float:
After using tin foil to make shapes that can carry cargo, test how many marbles/rocks/seeds they can carry before sinking. Discuss how boats are constructed to carry a lot without sinking. Then add a little flow to the water by moving a finger or stick through it to see if the boat and cargo can still float, and relate to how some boats are designed to carry cargo on rivers or oceans.
Pacific Northwest indigenous canoes are made from Western Red Cedar. The wood is strong, but lightweight. The oils make it buoyant and resistant to rot. Freight canoes travelling over open water are made large with high prows and sterns, so that they can ride the ocean waves without sinking.
Students can try experimenting with their foil boat shape and cargo to see how much water turbulence they can withstand.

Challenge 2:
Start with a 2x2x2cm piece of styrofoam. Add nails, paper clips and modelling clay to give it neutral buoyancy, so that it floats half way down the water (natural buoyancy). For this challenge, make sure the water is deeper. If not possible to achieve neutral buoyancy (hard), try and make the assembly sink as slowly as possible. At neutral density the combined density of the materials are the same as water density.

Calculate density using challenge 2:
To measure the density of their foam/nail/paper clip/modelling clay sculpture which floats as close to natural buoyancy as possible, students can use the mass/volume formula. Weigh the sculpture on a kitchen scale (in grams). Measure the volume of the sculpture: use a graduated cylinder (more accurate) or beaker (less accurate) that the sculpture can fit into, add water to the cylinder/beaker and read off the volume, then immerse the sculpture in the water and calculate the volume increase of the water (in ml). Divide the mass of the sculpture by the volume increase, to find its density (in g/ml). If the sculpture floated at near-neutral buoyancy its density will be close to that of water - 1g/ml. (Using a beaker to measure volume, we arrived at sculpture densities ranging from 0.7g/ml to 1.1g/ml - similar to the density of water. The lower numbers would be sculptures that slowly rise in the water and the higher numbers would slowly sink.)

Challenge 2 as an activity on fish movement in water:
Fish are able to swim at different levels in water - near the surface or deep, so that they can move to find food or hide from predators. Fish hold varying amounts of air in their swim bladder to change what level they are swimming at.
The activity using styrofoam piece with heavy items added to it models how fish float at different levels in water. The styrofoam holds air so that it floats (like the fish swim bladder) and the heavy loads pull it down in the water (like the fish body). Just as students balance the styrofoam with the weight of the objects added to achieve neutral buoyancy, fish can balance the amount of air in their swim bladder with their body mass to float at the level they need. This allows them to use their energy for moving back and forth, with no need for energy to stay at a certain depth
(Note: it might be a little confusing to students that fish regulate the amount of air, whereas this activity regulates the amount of mass, but the net effect of floating at varying levels is the same.)

Free experimentation exploring how air in fur or feathers makes animals buoyant
Give students objects with air in them that float (e.g. dry cloth, ping pong balls, styrofoam, popsicle sticks or wood pieces) and objects that sink (e.g. marbles, paperclips, pipe cleaners, wet cloth) to experiment with. Discuss that some objects float because they have air in them. Similarly, animals that live in the water trap air in their fur (e.g. otter) or feathers (e.g. ducks and water birds), to help them float.

Age-dependent concepts on sinking, floating and buoyancy that might be useful:
Heaviness, lightness, density of an object: Things that sink are “heavier” than things that float, or more specifically, they have a greater “density” (more mass for their volume; more particles packed into the same space). If an object has a greater density than the water it will sink - hence solids tend to sink (unless they have air in them); and gases float.
Weight, buoyancy, displacement: When an object is placed in water, its weight (the force of gravity pulling on its mass) pushes down on the water. The water pushes back up on it, called the force of “buoyancy” (or “upthrust”). The object rests at a level where these forces are balanced. The force of buoyancy equals the weight of the water displaced, so if the object is denser than water, the force of its weight will be greater than the force of buoyancy and it will sink.
Surface tension: forces between the surface molecules that come into play if the object is small enough, and can make things float.

Try a series of activities to feel your muscles contract and find out what parts of your body they move.
Muscles can only contract (not extend), so they work in pairs to move limbs in opposing directions.
Remove any baggy material, to feel the muscle contractions more easily.

Biceps arm muscle:
Hold your hand under a table, palm up, and rest your other hand on the top of your upper arm. Push up on the table. Your biceps will bulge as it contracts. You can feel the same muscle contract, but not as dramatically, when you hang your arm by your side, then raise your forearm. When your biceps contracts it pulls on the bones of your forearm, so bending the arm at the elbow. If you are pushing upwards or lifting a load the muscle exerts more force by contracting more (so it feels larger).

Triceps arm muscle:
Lay your arm on a table, palm down, and feel the underside of your upper arm near the armpit with your other hand. Push down on the table to feel the triceps contract. The triceps works opposite your biceps to straighten your arm.

Quadriceps leg muscle:
Sit on a chair and rest your hands on your upper thigh. Lift your lower leg by straightening at the knee, and you should feel your quadraceps bulging as it contracts. The hamstring on the back of your upper thigh works opposite the quadraceps to bend your leg.

Gastrocnemius leg muscle:
Stand on your toes while feeling the back of your lower leg. The gastrocnemius is connected by the Achilles tendon to the ankle. When it contracts you raise your ankle.

Slice a tiny piece of meat from the chunk and lay it on a slide.
Use the needles/pins to tease apart the meat until thin strands become separated.
Lay the second slide on top, and squash it down to flatten the meat.
Look at the meat under the magnifier/microscope (10X, then higher magnification if you have it). Find areas where the meat is in a very thin layer, often around the edges of the sample.
Look for the long strands lined up next to each other in the meat - these are the muscle fibres. The muscle fibres are made up of many protein molecules lined up side by side, which slide past each other to shorten the muscle fibre. A muscle contracts when many fibres lying side by side shorten at the same time.