ingridscience

Static electricity: light a bulb

Summary
Light a fluorescent bulb with static electricity.
Science topic (2005 curriculum connection)
Physical Science: Electricity (grade 6)
Physical Science: Chemistry (grade 7)
Materials
  • fluorescent bulb
  • balloon
  • dark room or cupboard
Procedure

Take a balloon and fluorescent bulb into the dark room.
Rub the balloon on your hair. This will transfer electrons from your hair onto the balloon and charge the balloon with a negative charge.
Bring the charged balloon near to the fluorescent bulb, and the bulb will light.
If it does not work right away, keep charging the balloon and trying again.

The static electricity of the balloon energizes the atoms or the mercury vapour inside the bulb. (The wall electricity does the same thing when you plug the bulb in.) As the mercury releases this energy again, it gives off UV light. This UV light collides with the phosphors in the bulb (seen as a white coating), and makes them glow. The glowing phosphors light up the bulb.
This works with a fluorescent bulb, because it needs less energy than an incandescent bulb to give out the same amount of light.

Notes

I recall it also working when the fluorescent bulb is simply rubbed hard against a sweater - test again.

Grades taught
Gr 1
Gr 2
Gr 3

Static electricity sparks and lightning model

Summary
Make small sparks with static electricity. Can be used to model lightning.
Science topic (2005 curriculum connection)
Earth and Space Science: Weather (grade 4)
Physical Science: Electricity (grade 6)
Physical Science: Chemistry (grade 7)
Materials
  • aluminium pie plate with styrofoam handle, so it can be picked up without touching the metal (see first photo)
  • flat of styrofoam or foam, that picks up a charge when rubbed on hair
Procedure

Rub the bottom of the styrofoam/foam block on your hair. (Electrons transfer from your hair to the styrofoam, giving the styrofoam a negative charge.)
Drop the styrofoam upside down on a table or on the floor, so the negatively-charged surface is now up.
Use the handle to pick up the pie tin, then drop it onto styrofoam - do not touch the pie tin or styrofoam. (Electrons in the pie tin move away from the negatively-charged surface of the styrofoam, and so cluster on the top side of the pie tin.)
Very slowly bring the tip of your finger towards the pie tin. You should feel a tiny spark when your finger is very close, but not touching. (Electrons jump from the pie tin to your finger, to get away from the negative charge of the excess styrofoam electrons.) This spark is static electricity. Lighting is also static electricity, but with much more energy.

The pie tin is now short of electrons. Use the handle to pick up the pie tin again (so this charge is not lost). very slowly touch the edge of the pie tin with the tip of your finger. You should feel another small spark. (The pie tin, short of electrons, attracts electrons from your finger which jump across).

Drop the pie tin onto the Styrofoam tray again, and repeat. You can do this over several times before the sparks cease.

Lightning is static electricity:
A lightning bolt is a dramatic example of static electricity.
In a thundercloud water droplets are caught in the updrafts and lifted to the top of the cloud where they freeze. Ice and hail move down in downdrafts. Ice and water bump together and electrons are transferred making positive and negative charges.
The strong negative charge in the bottom of the cloud attracts positive charges in the ground, which move up the tallest objects. A “leader” of negative charge descends from the cloud seeking out a path toward the ground. When it gets close to the ground, a positive charge “streamer” reaches up to meet the negative charge. When the channels connect electricity flows and we see the lightning stroke, which may repeat until the electrical discharge is complete.
The electric field often discharges between clouds.
(Thunder: lightning heats the air around it to high temperatures (30,000 °C). The heated air expands explosively, creating a shockwave as the surrounding air is rapidly compressed. The air then contracts rapidly as it cools. This creates an initial crack sound, followed by rumbles as the column of air continues to vibrate.)

Notes

This activity is variably reliable, likely because of humidity in the air, as on humid (wet) days, objects don't hold static charges quite as well.
Best inside in the winter, when the air is heated and dry.

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

Static electricity: jumping rice crispies

Summary
Use a cloth to charge a plastic sheet, and make small objects jump around.
Science topic (2005 curriculum connection)
Physical Science: Force and Motion (grade 1)
Physical Science: Electricity (grade 6)
Physical Science: Chemistry (grade 7)
Materials
  • shallow tray e.g. shoebox lid
  • sheet of acrylic or other plastic (test it first!)
  • alternative to above items: large petri dish with lid
  • small piece of cloth to charge acrylic sheet or lid of petri dish (plastics seem to work well, also try wool)
  • small objects to pick up e.g. rice crispies, scraps of paper; also add others to test (try couscous, small styrofoam balls)
Procedure

Put a few of the small objects in the tray or petri dish.
Put the acrylic sheet over or put the lid on the petri dish.
Rub the top with the cloth.
The small objects will stick to the lid, and sometimes even dance up and down.

Allow students to free play and explore what objects dance and which don't.
They can take notes on what they find.

Maybe give them different cloths to try. Rubbing one's hand on the lid, instead of a cloth: works quite well when the hand is dry in an indoor dry environment.

Sometimes the effect will stop after a while - try turning over the plastic sheet.

Explanation:
When the cloth is rubbed on the plastic lid, electrons are transferred from one to the other (whether the cloth or the plastic lid takes the electrons depends on their relative positions in the "Triboelectric series"). The lid is now charged with a negative or positive charge. The small objects are attracted to this charge and so stick to the lid.

Grades taught
Gr 1
Gr 2
Gr 3

Wings

Summary
Focus on wings as an animal adapation. Use paper airplanes to model how birds can steer with their wings.
Curriculum connection (2005 science topic)
Life Science: Needs of Living Things (grade 1)
Life Science: Diversity of Life (grade 6)
Materials

Materials in the activities.

Procedure

Introduction
Birds fly. How?
They push air to make them move.
Air seems like nothing to us as we are heavy. Push air into your face - feel the particles in air brushing your skin as they hit it.
When a light bird pushes against air particles, they are small enough that the push makes them move.
And depending on which way they push, birds can make amazing maneuvers in the air.

Watch slow motion of birds flying https://www.youtube.com/watch?v=qThIyj1mLfs.
(Also trailer for movie with Cornell lab of ornithology: https://www.youtube.com/watch?v=LjQtRr4CKcc - 15 secs to 38 secs.)
Note: the shape of birds’ wings are different on the downstroke and the upstroke.
Watch how they adjust their wing and tail feathers to change their flight direction.

Split students into three groups for activity stations
Learn how to use a magnifier together, needed for one of the stations.

Flying station
(Make planes with students if time, otherwise have paper airplanes ready for use.)
Paper airplanes fly for the same reason that birds fly.
Fly a paper airplane - make it stay aloft as long as possible.
Fold the very back of the wings up (about 2cm fkap) - how does it fly? - should stay up for at least as long.
Fold the back of the wings down - should dive to the ground.
Fold one up and one down - one of them should twist.
Just as bending the paper changes the flight path, birds move their feathers to change their flight path.
Discussion:
Birds use muscles to move their feathers by tiny amounts and change their direction of flight.

Feathers station
Look and gently touch real chicken feathers.
Look at them with a magnifier to see details of their structure. (Optional: draw them.)
Sort them into types (wing, tail and body feathers).
Discussion:
Birds have several feather types, these and others.
They are shaped for their task - stiff for flying, fluffy for insulation.

Build birds station
Use the wings and tail pieces of the fins and wings activity.
Add wings and tails to a modelling clay body.
Make a bird like one in the drawings, or make up your own.
Discussion:
Many different shapes of bird wings - some for gliding, some for fast flying, some for long migrations.

Grades taught
Gr 1

Slime and Silly putty recipes

Summary
Make slime/silly putty and understand the underlying chemistry. Optional: make two different consistencies and understand their different properties in terms of the molecular structure in each.
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

For the classic "slime" recipe:

  • Tablespoon measure
  • Tablespoons of white glue same as number of students, plus a few
  • equal number of Tbspns water as white glue
  • 2 teaspoons borax mixed into 2 cups water
  • small (Dixie) cups, two per student
  • one coffee stirrer per student
  • 2 baggies per student

To make two different slime/silly putty recipes and compare consistencies:

  • 2 empty Dixie cups for each student
  • marker pen to label cups for each pair of students
  • 3 Tbspns water for each student, plus a Tbspn measure for each pair of students
  • borax in a cup for each pair - about 2 Tbspns, with 1/2 tspn and 1/16 tspn measure
  • stir sticks, 3 per student e.g. half coffee stirrers
  • 4 tspns white glue in each of two cups for each student
  • tray for each student
  • cornstarch on a plate
  • 2 baggies per student
  • towels for cleanup
Procedure

To make classic slime.
Make 50% white glue in water. Give students 2 Tablespoons each in a cup.
Mix 1 tspn borax into 1 cup water. Give students 1 Tablespoon each in a cup.
Students mix the cups together and stir quickly until combined.
(For measuring everything individually, use recipe 2 below.)

Play with the slime: it can flow between the fingers, but when it is suddenly pulled it breaks.
Chemical explanation of how slime is made:
The glue contains long molecules (called polymers). When borax is added it makes permanent (covalent) bonds between the glue molecules, called cross-links. These cross links form a branching web of glue polymer molecules, giving the slime its thick texture.
The following activity compares two different kinds of slime/silly putty, with different amounts of cross linking.
Chemical explanation of how silly putty behaves:
There are other bonds between the slime molecules (called hydrogen bonds), which are weaker bonds and can easily break and reform. When the slime is pulled slowly, a few of the hydrogen molecules break, but then reform with another adjacent polymer. As these hydrogen bonds continually break and reform, the slime stays in one piece but can flow and change shape. However, when slime is pulled on suddenly, many hydrogen bonds are broken at once, so it breaks apart.

To make two different slime/silly putty recipes, with different consistencies
Ask students to work on the tray, as this activity is messy.

First make the classic slime recipe as follows:
Give students their materials: 4tspns of glue in a cup, an empty cup, a squeeze bottle of water and a tablespoon measure, borax powder in a cup and a 1/16tspn or equivalent measure (I use two scoops of a very small measure).
Instructions for students:
To an empty cup, add 1 Tbspn water and 1⁄16 tspn borax. Mix well.
To 4 tspns glue in a cup, add 1 Tbspn water. Mix well.
Pour the borax mixture into the white glue mixture. Mix well.
Lift the blob out of the cup, and into a small baggie.
Mould with hands through the bag to mix completely.
Pull the blob out of the bag, leaving any liquid behind.
Mould with hands until smooth.

Allow students time to play with their slime.
If slime is not stretch enough, gradually work in some more water.

Discuss how and draw how the borax molecules cross link (or bridge) the long glue molecules, binding them together so that the glue is more solid but can still flow.

Then make another slime recipe:
First tell students that they will add a lot more borax to this recipe and ask what more cross links of borax will do to the texture of the slime that they make [it will be more solid].
Do the experiment:
To an empty cup, students add 1 Tbspn water and ½ tspn borax. Mix well.
Pour the borax mixture into the cup of 4 tspns white glue. Mix well.
Lift the blob out of the cup, rest for 5 minutes.
Mould with hands into a ball.
Roll in cornstarch to make less sticky.

This recipe makes a much more solid ball, which can be bounced.

Review the consistencies in terms of the molecules that make silly putty (see last photo):
In a chemical reaction, the borax molecules bridge (or "cross-link") the glue molecules together, turning the two liquids into something more solid.

Other background chemistry: White glue is a polymer, which is a long chain of repeating units. Other polymers are nylon and plastics, as well as naturally occurring rubber. Polymers can be cross-linked at any of the repeating units along their chain, so the amount of cross-linking determines how solid they become.

Slime is a non-Newtonian fluid - its viscosity changes depending on how much force is applied. (Standard Newtonian fluids only change viscosity with changes in temperature.) When a sharp force is applied to slime it becomes rapidly more viscous and behaves more like a solid.
More info on slime: http://www.acs.org/content/dam/acsorg/education/resources/highschool/ch…

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

Heat and Rates of Reaction

Summary
Use light sticks and dry ice for a dramatic lesson on rates of reaction and how they change with heat.
Curriculum connection (2005 science topic)
Physical Science: Properties of Matter (grade 2)
Physical Science: Chemistry (grade 7)
Procedure

Compare how brightly light sticks glow when dipped in hot and cold water, and discuss rates of this chemical reaction.
Observe the dramatic reaction of dry ice turning to gas as it is added to warm water.
Add detergent to make dry ice bubbles.

Review the chemistry of the lesson:
The light sticks glow because a chemical reaction makes a new glowing molecule. The rate of this chemical reaction can be sped up by dipping the light stick in warm water, or slowed down by dipping in cold water.
Dry ice sublimes at room temperature, making clouds of carbon dioxide gas in the air, and violently bubbles as the gas is rapidly formed in warm water.

Grades taught
Gr 2
Gr 3

Dry ice source

Summary
Source of dry ice pellets. Bring a styrofoam container, or you will need to buy one there.
Curriculum connection (2005 science topic)
Physical Science: Properties of Matter (grade 2)
Physical Science: Chemistry (grade 7)
Type of resource
Store
Resource details

Praxair, now Linde. 2080 Clark Drive, Vancouver BC

Dry ice in water

Summary
Add dry ice (solid carbon dioxide) to warm water and observe a dramatic state change from solid to gas.
Science topic (2005 curriculum connection)
Physical Science: Properties of Matter (grade 2)
Physical Science: Chemistry (grade 7)
Materials
  • dry ice in styrofoam box, see reference for source
  • thick glove (e.g. gardening glove) to handle dry ice
  • tub or tray of warm water for a group of 3-4 students
Procedure

Show students a chunk of dry ice (only hold with thick gloves, as it will give cold burns to skin). It is carbon dioxide in its solid state and is very cold, -80ºC! The solid carbon dioxide does not stay solid very long in a warm room, but instead of turning to a liquid then a gas, it turns straight into a gas - called “sublimation”. The gaseous carbon dioxide can be seen as white clouds surrounding the solid chunk of dry ice.

For each student group around a tub of warm water, drop in a few nuggets of dry ice. The students must not touch the dry ice.
The warm water will dramatically speed up the state change from solid carbon dioxide to gas: large bubbles of carbon dioxide gas form in the water. At the surface, warm water that has evaporated comes in contact with the cold carbon dioxide gas and re-condenses into tiny droplets, forming white clouds. The white clouds, a mixture of water droplets and carbon dioxide gas, spill over the sides of the container and fall to the ground (as carbon dioxide is heavier than air).

If the reaction slows before the dry ice is used up replace the water with more warm water.

If you allow most of the dry ice to sublimate in the tray, small pieces will float to the surface of the water, and spin and zoom around. As gas projects from one side, it pushes the dry ice it in the other direction (Newton's Law of action and reaction). If the gas comes from an angle it will start it spinning.
It behaves as a hovercraft does - the gas escaping from the bottom of the dry ice piece makes a layer of gas between the dry ice and water, so that it can skim with very little friction over the surface of the water.
The small pieces are safe to touch briefly, so students can redirect the direction of the dry ice pieces with a light touch.

Grades taught
Gr 2
Gr 3
Gr 4
Gr 5

Heat transfer and sources

Summary
Experiment with ways that heat can be transferred (conduction, convection, radiation) then look at how we make heat.
Procedure

Introduce heat (also called thermal energy), and that it can move from place to place.
It can move by Radiation (as waves, like light), Conduction (between materials that are touching) and Convection (flowing in a gas or liquid).
Ask students to rub their hands together to make heat by friction.
Brainstorm on sources of heat.

Do a selection of the activities.

My favourite sequence:
Use a heat lamp in a circle to introduce radiation.
Look at IR images together and discuss sources of radiation.
Hand out Heat sensitive sheets to introduce conduction.
Allow free play with the sheets (using the heat lamps to charge them), so exploring radiation and conduction.
End back at the circle for a convection demonstration.

Activity descriptions:

Heat sensitive sheets are super fun and demonstrate conduction and radiation (but are expensive).
Outdoors on a sunny day, the sun heats them up with its radiation. Warm playground equipment or walls can heat them up by conduction. Shadows or cool water make patterns on them.
Indoors, heat lamps heat the sheets up by radiation. By touching classroom surfaces they are cooled down by conduction.

Activities that show different ways that heat can move:
Convection activity: heat convection demonstration (can use hot water from a thermos if outdoors).
Convection activity indoors (where there are no drafts): candle heat pinwheel
Radiation indoors: infra red heat lamp demonstration then free play with heat sensitive sheets (radiation and conduction).
Heat sensitive sheets can be heated up by radiation from a lamp, and cooled by conduction.
Conduction activity (needs electric kettle, so indoors easiest): heat conduction in different materials.

Heat sources activity.
Show infra red camera images to show sources of infra red radiation (e.g. a house with windows radiating heat, a dog with heat radiating from parts of its body, also IR images of galaxies).

End by summarizing ways that heat can travel.
Both conduction and convection need molecules to transfer the heat energy.
Radiation does not need molecules. The sun is a source of radiation and travels through the vacuum of space to reach Earth.

Grades taught
Gr 2
Gr 3
Gr 4

Heat conduction

Summary
Learn what heat is, and investigate how it moves within and between materials.
Curriculum connection (2005 science topic)
Physical Science: Properties of Matter (grade 2)
Physical Science: Chemistry (grade 7)
Procedure

For younger students heat can be referred to as energy. For older students, what is happening in terms of molecules is helpful.

Review states of matter: molecules in solids, liquids and gases.

Demonstration to discuss what heat is (energy; the speeding up of molecules): Heat conduction in a metal rod.

Experiment to investigate how fast heat moves in different materials.

Relate how heat moves to every day experiences with activity: What materials feel warm?

Notes

For grades 2/3, explaining in terms of molecules was too confusing. Stick with heat as energy for all explanations for this grade.

Grades taught
Gr 2
Gr 3