ingridscience

This recipe makes just over 2lb.

Mix ingredients together in a pot over medium heat.
Stir constantly as the mixture heats up.
Once it starts to make a paste, remove from the heat, keep stirring until it is all playdough consistency.
Put in a large ziplock back and knead every few minutes as it cools.
Keep sealed.

If some of the playdough dries out, just knead it into the mass again.

Double this recipe makes enough playdough for a class of 24 students, with a golf ball-sized piece of playdough each.

If using floral wire, fold one end into a triangle, push through a base or tape to a desk, then wrap it in a large piece of aluminum foil. Bend into a curvy shape. If using copper wire/steel strapping (first photo only) bend them into a curvy shape then attach one end to a desk or base.

Using tape or binder clips, attach the bulb/buzzer then the battery/batteries, from the base of the curvy piece made above.
Then from the battery, add on a longer piece of wire (home-made or purchased), which can easily reach to the top end of the curvy piece.
To the end of this long wire, clip a loop of tin foil or metal.

Test the circuit - when the small metal loop touches the curvy piece the bulb should light or the buzzer should sound. If it does not, redo the connections one by one and check each time for the bulb lighting.

To play the game:
Move the loop from the top of the curvy piece all the way down to its base without touching it. If you do touch it, you will close the circuit and the bulb will light/the buzzer will sound. How far can you go? If it is too easy, make the loop smaller, or the curvy piece more wiggly.

Students make a circuit containing a bulb and a battery, but keeping it open so that they can turn the light on and off.
Give students a morse code sheet (found online), and ask them to pair up to send each other messages with morse code. Try one letter at a time to start before sending a very short message.
Discuss the skill required to send and decode morse code fast.

Students build a circuit by taping the components to the board, initially with a battery and bulb, to test the circuit. The bulb should light when the circuit is closed (makes a loop).
Show them how to open the circuit up, so that they can place objects to test in the gap, to see if they conduct electricity (and therefore light the bulb). They may need to add an additional wire to make components reach.

Provide test materials, and also encourage students to walk around the classroom with their board, testing materials that they come across. (They may need to add in an additional wire so that their circuit can reach off the board for testing.)

Summarize together - metals conduct (that is why electrical wires are made of metal).
Plastic and styrofoam are insulators (that is why electrical wires are covered in plastic, and why we used a styrofoam base for our circuit).
Carbon also conducts.

For older students, materials conduct when they have free electrons that can move within the material to make a current.

Does water conduct? Try it. No. Why are we so concerned about electrical appliances in the bath? They are with much higher voltage, and it is only a problem if it goes across your heart.
Try other liquids, solutions of kitchen chemicals (baking soda, sugar, lemon juice, vinegar) - also see the electrolysis activity.

See electric circuits with home-made wires and bulbs for a very similar (and better) activity.

In your house, when you flick the switch, the light comes on. We’ll make our own light come on.

Here’s your bulb. Draw the bulb on the board. White paper behind a bulb to see the wire element better. When electricity squeezes through the thin wire it makes it so hot it glows.
Screw into a bulb holder and show how it connects to the bulb connectors.

Wire one end of the battery holder to the bulb. Wire the yellow piece of wire to the other side of the bulb holder.
Add a battery. Touch the wire ends together to light the bulb. Add blobs of foil to the end of each wire to make a better connection.
Draw the circuit on the board.
Students can join their circuits in a circle to light all their bulbs at once.

Add a cardboard base for each student to make the parts stay in one place: secure the battery holder with a loop of duct tape, and tape the bulb holder to the board.

Giant bubbles outside as demonstration.
Students make frame from a loop of string and two straws.
Make own bubbles.
Watch the changing shape and colours in the giant bubbles.

The colours are due to the structure of the bubble skin - two layers of molecules, which separate white light into its colours.

Make a foam drink, by adding air bubbles to milk.

Give students a cup of milk and a straw (and a squirt of flavouring).
Ask them to blow bubbles in their drink to make foam, then drink their "milkshake".

The bubbles are air blown into the drink, which are stabilized by components in milk.

Optional: do the foam molecule test on the component molecules of milkshake (protein, fat, sugar), to find out which ones make the foam. (The fat and protein.)

The foam is a kind of mixture called a colloid.
See the attachment for other kinds of colloids and mixtures.

Pour your bubble mix onto a black plate (about 20ml each). Use a straw to blow as large a bubble as possible (blow long and slow).
Look at the colours. Hold a sheet of white paper behind the plate at an angle to see more colours.
Why are they there? Made by the layers of soap molecules - refer drawing of structure to explain. (Light is made of many colours - when white light bounces of the first layer and the second layer the colours interact with each other and some colours are taken away leaving the others - called interference). So see all the colours in white light.

The colours in oil or on a CD are formed in the same way. Rainbow colours and colours from a prism are also formed from the separation of white light into its component colours, but by a different mechanism (refraction).