ingridscience

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.

Either use as a demonstration, with discussion as each part of a leg is found.
Or partially dissect a leg before hand (remove skin and expose some tendons) for students to discover the parts.

Step by step dissection of the leg and the function of the parts revealed:

1. Find the muscles
If there is skin, peel it off the chicken leg. The pink meat under the skin is muscle.
Find the lower leg (drum stick) and upper leg (thigh), and the knee between them. Also find the ankle at the end of the drumstick (the foot has been cut off).
The chicken can contract (shorten) one set of thigh muscles to bend it's leg at the knee, and muscles on the other side of the thigh to straighten it. The same happens in our leg - muscles on the front and back of our thigh respectively straighten and bend our leg.

2. Find the tendons and the muscles they are attached to
(The tendons attach the muscles to the bone, so that when the muscle contracts it pulls on the bone and makes the leg move.)
Cut the chicken leg down to the bone around the ankle. This should reveal the strong, white, stringy tendons.
You can feel your own ankle tendons: the large Achilles tendon at the back, and many smaller ones in front (easier to find if you raise your foot).
On the chicken leg, follow the tendons up to a muscle and carefully separate the muscle. This will require carefully slicing through a thin membrane. The several muscles of the lower leg can be separated out. Each muscle can work independently and with others so the chicken can move its lower leg in different ways.

3. Find the leg joints
Cut through the muscles over the knee to reveal the two bones joining at the knee. You might also find the connective tissue protecting the bones and preventing them from rubbing directly against each other, and the ligaments holding the bones together. Bend the chicken leg at the knee and watch how the bones move past each other - this is a hinge joint. Your knee bones work in a similar way.
Cut through the muscles at the hip joint at the top of the thigh, to find the hip joint where the upper leg meets the leg (a ball and socket joint).

4. Find the bones
Just like us, the lower leg of a chicken has a large bone (the tibia), and a small fibula. In humans the fibula runs the length of the lower leg, but in a chicken it is a tiny spiky bone, extending only part way down the leg.
Both chickens and humans have one bone, the femur, in the thigh.

Explain to students that they will be measuring how fast their neurons can transmit information in this activity. They will be using their neurons to see and to contract their muscles, as well as neurons that send messages between these two processes.

Give each pair of students a ruler. Demonstrate how one student rests their arm on the edge of a table their hand hanging over the edge, and holds their thumb and index finger a couple of cm apart. The other student of the pair holds a ruler so that the 0cm mark is between the thumb and finger. Without warning, the ruler is dropped and the partner closes their fingers on the ruler to stop it as quickly as they can.
Students should record the catch distance each time, doing several trials before switching roles with their partner.
They can try the activity with their dominant and non-dominant hand, as well as being distracted while talking about something different.

Ask students to find the mean of their data, and record their average catch distance.
Convert catch distances to reaction time:

From https://letstalkscience.ca/sites/default/files/2020-11/Testing%20Reacti…

Hockey goalies, and other people in high-speed sports need to have very fast reaction times. They would be able to catch the ruler at about 11cm, giving a reaction time of 0.15 seconds. Some students might have reaction times this fast, but most will fall between 15cm and 20cm (reaction times from 0.18 - 0.2 seconds).

With our rulers, our students got average catch distances of 10, 23, 19, 15, 10, 16, 18, 18cm.

Discuss how with any reaction time, it is amazing how fast the processing happens.
Show image of pathway, then trace pathway on a real brain if possible: the eye sees the ruler drop and a message is sent along a neuron to the thalamus in the centre of the brain, from which another neuron sends a message to the visual cortex. Once the image of the ruler dropping is perceived, there is a signal to close the fingers, down one neuron from the motor cortex to the spinal cord. Then a second neuron all the way from the spinal cord down the arm to the finger muscle. Then the finger muscle contracts.
All this takes milliseconds. The slowest part is the message passing between neurons; the neurons themselves transmit the electric message very fast.

Try two activities, to experience how your muscles help you keep balance.

1. Stand with your legs apart, your feet spaced at least as wide as your shoulders.
Try to lift and hold your right foot off the ground without moving your upper body - you'll need to put your foot down again quickly as you start to fall.
Now lift your right foot off the ground while allowing your upper body to move, so you can keep balance one one foot. Notice how you changed your body position so that your upper body is over your left foot. Your left leg muscles worked together to shift the weight of your body over your left leg. And now that you are standing on one foot, the muscles in your left leg are constantly adjusting to help keep your balance.
For younger students, it might be best to start with them standing against a wall to prevent them from moving their upper body: Put your left shoulder and foot against a wall. Try and lift up the right foot. It is impossible because you can't shift your weight to balance because the wall is in the way.

Dancers and gymnasts have strong leg muscles because they use them constantly to balance in many different positions. To be able to hold a pose, the dancer's/gymnast's centre of gravity must be directly above the area of contact with the floor.

2. Put your back and heels against a wall. Try and touch your toes without moving your feet.
Now try the same movement without the wall.
A wall makes it very hard to stay balanced while bending down. Without the wall, our muscles work to shift our body dramatically to keep our weight centered over our feet, so that we can stay balanced. We are often not aware of these constant adjustments our muscles are making to keep us balanced.

During sports our body moves a lot. As we kick, hit or move an object, many forces act on our bodies. Our muscles are constantly working to counteract these forces and keep us balanced.