ingridscience

Solutions

Summary
Make crystals and understand the chemistry of dissolving and crystallization, as water is added to then removed from a solution. Separate the components of a solution through chromatography of marker pen ink. Use red cabbage dye to measure the pH of household material solutions.
Curriculum connection (2005 science topic)
Physical Science: Chemistry (grade 7)
Procedure

Introduce what a solution is - a mixture where the particles are evenly distributed and completely mixed up.
Do a selection of the activities to show how solutions can be made and separated (crystal making, and chromatography), and how concentration of solutions can be measured (red cabbage dye as a pH indicator).

Do the Epsom salt crystal activity, to show formation of a solution, then separation of components by crystallization.

The chromatography activity shows another method of separating components of a solution. This method is used a lot by chemists and forensic scientists, and was used to discover the structure of insulin.
Optional extension: forensic chromatography with black pens.

To explore the concept of concentration, use red cabbage dye to measure the pH in various household materials. Also introduction to acids and bases.

The sugar crystal activity makes edible crystals, but note that the crystals will not be ready for a few days.

Notes

True?
Air is a solution of gases (oxygen, nitrogen, etc.).
Brass, an alloy of copper and zinc, is a solid solution.

Grades taught
Gr 3
Gr 4
Gr 5
Gr 6

States of Matter and State Changes

Summary
Define/review solid, liquid and gas. Do activities that show state changes. Optionally include a snack made through state changes.
Procedure

Do a selection of the activities.

Indoor activity ideas:

Introduce/review that everything is made up of tiny tiny particles, too small to see. (An atom is 10-10m, or 10 million in a dot one mm wide.)
In a solid the particles are packed close together, that is why a solid feels hard. In a liquid they are further apart. In a gas they are far enough apart that we can move through them easily - move your hand through the air and the wind you feel on your hand is the molecules bumping into your hand.
Either ask students to point to examples of the states in the classroom, or do the states of matter scavenger hunt.
[Some students may also point out that plasma is also a state of matter, which it is. The sun contains plasma.]
Optional: book on states of matter: “Matter” First Fact book (Capstone Press)

With classroom or hallway space, act out the states of matter to model what the particles are doing in each state (maybe using water in epsom painting as an example for liquid to gas).

If doing frost, set up before the next activity.

Epsom salt painting: show epsom salts dissolving in water to show students what is in the solution that they will paint with. As the students paint and see crystals forming, describe how the water evaporates from the paper, leaving behind the epsom salts.

Look at state changes in water (including the icy frost formed on the cans, if they were set up).
Optional: as part of this activity measure the temperature of water in the different states of matter.

Dancing raisins is a simple activity on state changes and density that can be extended into interesting discussions.
Note that dissolved carbon dioxide gas is no longer a gas, but in a "dissolved state".

A snack that exploits state changes:
Popcorn and skits, or ice cream. Students can act out what is happening to the molecules as they change state to make the snack.

For an outdoor lesson (no electricity available):
Start by introducing or review the concept of solid, liquid and gas.
Optionally act out the states of matter
Demonstration of molecules moving in warm and cold water
Optionally, with older students, act out the molecules in warm water and cold water: students have two different coloured cards, to show that the card colours mix up more if there is more energy (warmer water) and mix less with less energy (cold water).
Dry ice in water to show state changes of carbon dioxide and water at different temperatures.
Dancing raisins, to show state changes and relative densities of raisins that sink and float (with attached gas bubbles).

Grades taught
Gr 1
Gr 2
Gr 3
Gr 4
Gr 5
Gr 6

Air pressure in a bottle

Summary
Blow into a bottle with a piece of paper in its mouth. Surprise when the paper comes towards you.
Science topic (2005 curriculum connection)
Physical Science: Properties of Objects and Materials (grade K)
Physical Science: Properties of Matter (grade 2)
Physical Science: Chemistry (grade 7)
Materials
  • recycled drink bottle with a wide mouth
  • small piece of paper, that when crumpled into a ball, takes up half the mouth of the bottle
Procedure

Crumple the paper into a ball.
Place it in the mouth of the bottle.
Blow into the mouth of the bottle.
What happens?

The paper will usually shoot out of the bottle towards you!
If it does not, check that the paper ball does not take up more than half of the diameter of the bottle opening.

Why?
When you blow into the bottle, you add air to it, which increases the pressure inside.
The higher pressure air in the bottle will move towards the lower pressure air outside the bottle.
In flowing out of the bottle it pushes the paper out.

Grades taught
Gr 4
Gr 5
Gr 6
Gr 7

Carried by Water

Summary
Do a series of activities showing water as a medium that carries, mixes and separates chemicals, which links the life and the rocks of planet earth.
Procedure

Introduction:
Water itself is essential for life on earth. It also carries chemicals that nourish life, form our landscape and makes things change.
Students rotate through three activities, with discussion at the end on how they relate to water.

1. Growing epsom salt crystals
This water carries a salt. When the water evaporates it leaves the salt behind, which organize into crystals. The longer the solution takes to dry, the longer the crystals are.
Big picture: Water carries salts, minerals and nutrients, bringing them to new places. They are used by living things, and are deposited as mineral crystals or rock formations.

2. Red cabbage dye
Water can be used to extract dye molecules from plants.
Discuss indigenous dyes as the class makes red cabbage dye as a group.
Some dyes, including this red cabbage dye, can change colour depending on other components of the water (acids and bases).
The different colours made can be used to dye cotton cloth or yarn.
Big picture: Water carries the colours in plants. Plants can be crushed to bring out the colours in them, which can be used as dyes. Some dyes change colour depending on the amount of acid or base in the water. Many colours in living things are dependent on the amount of acid or base in the water in them.

3. Separating colours with chromatography
Dyes are often mixed together to make new colours. We can use water to separate them.
The different colours making up the ink are pulled along by the water to different extents, so some move faster and some move slower. The different rates mean that the colours are separated out.
Big picture: water carries along rocks, silt and chemicals. Depending on how easily they are moved by the water, they will be deposited in different places.

Grades taught
Gr K
Gr 2
Gr 3
Gr 4
Gr 5

Water flow, Ocean Currents and Connectedness

Summary
Explore ways that water flows in rivers and/or the ocean. Discuss how it connects the regions of the planet and the living things that rely on the water.
Curriculum connection (2005 science topic)
Earth and Space Science: Air, Water and Soil (grade 2)
Earth and Space Science: Renewable and Non-Renewable Resources (grade 5)
Procedure

Run two or more of the activities, back to back, or as stations. (Either way this is an intensive lesson for materials prep.)
Ideas for overarching themes: Water Flow; Indigenous People’s relationship with Water and its connection all Life; Ocean Current formation; Animals using Ocean Currents.

The Stream flow and erosion activity shows how water flows downhill and carves out the landscape to make valleys and mountains. Flowing streams and rivers bring water to animals and plants and bring food to living things.

The Water flow with temperature and salt variation activity shows how global ocean currents arise and circulate around the planet.
The ocean currents cause upwelling of deep ocean water, which moves nutrients to the surface for life there. Ocean currents are also used by animals for migration e.g. Loggerhead turtles migrate from Florida to the open ocean (where the young are safer), then return as adults. Atlantic Leatherbacks travel from Caribbean to Nova Scotia to feed on jellyfish. Pacific Leatherbacks have the longest migration on Earth: they are born in Japan, migrate to Mexico to feed on crabs, then head back to breed, nest. The Green Sea Turtle rides the East Australian Current, though does not go out into the open ocean (Crush in Finding Nemo).

The Turbulence activity show how winds change the flow of water on the surface of the ocean, and land masses change the flow of water to produce vortices (swirls of water). The movements mix up the water, bringing food to animals that can’t move, and moves nutrients and heat around.

Complex world-wide ocean currents result from the surface currents of the ocean conveyer belt combined with local turbulence - see them on the mesmerizing NASA perpetual ocean video: https://svs.gsfc.nasa.gov/10841 or https://www.youtube.com/watch?v=WEe1bVjORN4
Use this video to show global surface ocean currents, as well as vortices formed by land masses that interrupt these large flows.

Notes

Lesson extension: On a world map, draw in the migration routes of turtles and whales (?give students countries/cities to join). Show them real migration paths (wiggly) so that they can make them look realistic. Add the ocean conveyer belt currents to the map, to see which ones the animals use in their migrations. ?Find the circles of ocean currents that form gyres.

Grades taught
Gr K
Gr 2
Gr 3
Gr 4
Gr 5

Coloured lights change objects' colours

Summary
View a coloured design on cloth or paper under different coloured lights. Understand how the colours of objects change depending on the light they are viewed under.
Science topic (2005 curriculum connection)
Physical Science: Properties of Objects and Materials (grade K)
Physical Science: Light and Sound (grade 4)
Materials
  • light that can change colour (LED lights that you can slide between the colours work great)
  • cloth with pattern of different colours, or printed images
  • room that can be darkened
Procedure

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.

Turn out the room lights.
View the cloth under different light colours and see how the cloth colours change.
Colours will look their normal colour, a different colour or even black.

The colours appear in the cloth because of the colours (wavelengths) of light they reflect.
If white light hits them (as we usually have with the sun or room lights), the cloth will absorb parts of the white colour spectrum and reflect others - the reflected colours are the ones that we see.
However if only part of the white light spectrum hits the cloth, it is only able to reflect that part of the spectrum. If the cloth is white it will reflect all the colours hitting it, so will look the same as the light colour. If the cloth is another colour, it will still absorb some of the wavelengths, reflect some, and maybe appear a different colour.
For example, a red piece of cloth will reflect red light and absorb all other colours. So if a red light hits it it will appear red, but if a blue light hits it it will appear dark because it absorbs the blue light and reflects no light.
In the photos above, the colours that are fuchsia-coloured in white light (first photo) appear blue in blue light (second photo) and brown in green light (third photo). The pink reflects mostly reds and blues. With blue light hitting it, it can only reflect blue so appears blue. With green light hitting it (a mixture of yellow and cyan), it does not reflect many wavelengths, so appears a darker. Check the last light colour mixing image to see how light colours mix.

Notes

I have only done this with a small group. With larger classes it will be hard as everyone wants to control the light colour, rather than just watching. Need to wait for even cheaper LEDS so they can all have one maybe in a shoebox.

Grades taught
Gr 4
Gr 5

Sun's angle on earth

Summary
Use a flashlight on a large ball to show how the intensity of the sun varies between the equator and the more polar regions
Science topic (2005 curriculum connection)
Earth and Space Science: Stars and Planets (grade 3)
Earth and Space Science: Weather (grade 4)
Materials
  • large ball e.g. exercise ball
  • flashlight with a beam that can focus to a circle
  • darkened room
  • chalk
Procedure

Explain that the ball is a model of the earth. Check that students know where the equator, poles, and their own city are.
Turn the room lights off.
Hold the flashlight level with the centre of the ball, from a couple of metres, so that a circle of light falls on the equator. Ask a student to draw around the circle. This models the sun's rays reaching the equator.
Keep the flashlight at the same distance but move it up so that it now shines on a more northern region of the "earth". Ask a student to draw around the patch of light on the ball now - it should be an elipse. This is how the light falls on the more northern regions.
Turn the room lights on and compare the outlines of the light patches. Discuss the intensity of light in each of the regions - it must be more intense at the equator as it covers a smaller area.

Explain that in the same way, the equator of the earth receives much more intense sunlight than the more northern and southern latitudes.

Relating to how weather starts, the tropics are warmed up more by the sun, and the warmer land and ocean there means the air above it is heated up more.

The sun's angle on Earth helps determine why we get different biomes;
Biome map: https://askabiologist.asu.edu/sites/default/files/resources/articles/bi… (from this article - https://askabiologist.asu.edu/explore/biomes) or https://cdn.britannica.com/38/102938-050-6B5388D9/distribution-biomes.j… for terrestrial (Earth, not water) biomes.

Notes

Tape a map of Earth Biomes onto the ball?

Grades taught
Gr 1
Gr 2
Gr 3
Gr 4
Gr 5
Gr 6
Gr 7

Heating land and water

Summary
Model the heating of land and oceans on earth using a lamp, sand and water. Measure the temperature rise in each.
Science topic (2005 curriculum connection)
Earth and Space Science: Air, Water and Soil (grade 2)
Earth and Space Science: Weather (grade 4)
Materials
  • plastic shoe box
  • incandescent bulb (100W) and holder (with reflective screen work best)
  • masking tape
  • two shallow tubs
  • 150ml dry sand
  • 150ml water
  • two thermometers
Procedure

Note: pour water into the tubs a little ahead of time so that they reach room temperature (and start at the same temperature as the sand).

Add sand to one tub and water to another and place side by side in the plastic box. Add the thermometers so that they are submerged in the material, and read the temperature.
Lay the light over the box so that it is equally far from the tubs of sand and water. Leave for at least 5 mins, then take the temperature again. Take additional measurements over 20 minutes or more.
Graph the results.

For younger students plot the temperature reading at each time point.
Older students could alternatively calculate and plot rise in the sand and water, then add each as a single point to the graph. Data cleaner this way, but need to understand a rise in temperature.

The sand heats up much more quickly than the water.
In the same way, then sun heats up the earth's land (especially deserts) more quickly than its oceans, which means that living things in each environment have different adaptations suited to each environment.

This difference in heating between land and water also means that the air above the land heats up more than the air above the water, creating temperature differences therefore air movements.

Notes

Silver lamps with reflective shield way more dramatic than standard desk lamps (more heat from them, yet water temp still rises very slowly).

If doing this activity with back-to-back classes, replace the water and sand in the tubs, or make sure there is time for it to cool off (20 mins?).

Grades taught
Gr 2
Gr 3
Gr 4
Gr 5
Gr 6
Gr 7

Black snakes

Summary
Ignite sugar and baking soda to make black snakes of carbon puffed up with carbon dioxide gas.
Science topic (2005 curriculum connection)
Physical Science: Chemistry (grade 7)
Materials
  • sand
  • flammable fuel
  • icing sugar
  • baking soda
  • match or lighter
Procedure

Mix 4 teaspoons icing sugar with1 teaspoon baking soda.
Make a pile of sand on a heat-proof surface, and make a dent in the middle of it.
Pour fuel into the dent, then add some sugar/baking soda mixture.
Light it.

Long black "snakes" of carbon are extruded, made up of carbon and carbonate, puffed up with carbon dioxide gas. They crumble when they are touched (and make your hands black).
The reaction smells like marshmallows over a fire.

The chemistry:
C12H22O11 (sucrose sugar) + 12O2 → 12CO2 + 11H2O (g). This is complete combustion of the sugar in oxygen, which produces heat which makes the reaction continue. The water vapour escapes.
There are also some reaction products that are not made with oxygen (which happen in the centre of the pile):
C12H22O11 (sucrose sugar) → 12 C (black of the snake) + 11 H2O (gas).
2 NaHCO3 (baking soda) → Na2CO3 (carbonate that is also part of the snake) + H2O (gas) + CO2 (gas, which puffs up the snake)

Notes

Try without the sand - add the sugar/baking soda mixture to a metal bowl, pour on the fuel, then light.
Much more dramatic here: https://www.youtube.com/watch?v=sinQ06YzbJI ('Fire Snake' at minute 2:35)

Grades taught
Gr 4
Gr 5

Forces: chains of forces and combining forces

Summary
Introduce forces and how they are passed from one object to another with the coin game. Then jumping stick or catapult to show chains of forces passing between different materials. Air resistance a surprising force with good discussion.
Curriculum connection (2005 science topic)
Physical Science: Force and Motion (grade 1)
Physical Science: Forces and Simple Machines (grade 5)
Procedure

Forces make things move, or make moving things stop. Another name for a Force, which is easier to envision, is a Push or a Pull.

Start with coin game, either as a demonstration or for students to do at their desks.
Summarize that there is a chain of forces between the coins that make them move in different directions.
The size of the coin changes how much force is transferred to another coin.
The force of friction changes how coins move on a smooth surface vs a carpet.

Another chain of forces in a jumping stick toy or a catapult.
Grade 2 and up can make jumping stick
Primaries can make torsion catapult (adult assistance needed for youngest grades)
Grade 2 and up can make a more powerful tin can catapult (adult assistance needed for primaries)

Allow free play and optionally measuring and recording of distances, before regrouping to discuss the specifics of the chain of forces.
Forces make the parts move, and also make them eventually stop.

End with counteracting forces:
We have seen that forces make things move, and that forces make things stop.
The balancing of opposite forces determines whether something will stop or slow down. When something slides along the floor, the forward movement is balanced by the friction against the floor. When something is falling the force of gravity is balanced against air resistance, pushing up against the object.
Air resistance activity with the two paper plates works well as a demonstration with discussion.

Notes

Add electrostatic force as a non-contact force: do as a demo with one of the students (the one with the best hair for it)

Grades taught
Gr K
Gr 1
Gr 2
Gr 3
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