Ist Ermington Scout Group



Science Night- ExperimentsBALLOON STATICEquipment:balloonswater faucetjumper (preferably wool)paperInstructions:Tear the paper into small pieces and put them on the table.Blow up the balloon and tie the end.Rub the balloon on the jumper.What happens when you hold the balloon on the wall in a warm, dry room?What happens when you hold the balloon near running water?What happens when you hold the balloon over the torn pieces of paper?Everything around us is made up of tiny parts called atoms, and atoms are made of even smaller parts, which are called protons, electrons and neutrons. The protons, electrons and neutrons are very different. Protons have a positive (+) charge. Electrons have a negative (-) charge. Neutrons have no charge. Usually, atoms have the same amount of electrons and protons. When the atom has no charge, it is 'neutral'. If you rub things together, electrons can move from one atom to another, then some atoms get extra electrons and the other atoms might have a negative charge or no charge at all. When charges are separated like this, it is called static electricity.DANCING SULTANASEquipment:A clear plastic cupTap waterSome sultanasA tablespoonBaking soda (also called bicarbonate of soda)White vinegarInstructions:Fill the plastic cup with tap water until it's about three-quarters full.Stir in two big spoonfuls of baking soda until it's dissolved.Drop a few sultanas into the cup.Pour into two big spoonfuls of vinegar. What happens to the sultanas?First, where do the bubbles come from? When the vinegar and the baking soda are mixed together, we get a chemical reaction between them. This produces carbon dioxide gas, which you can see as the bubbles that fizz up when the vinegar is added.Second, why do the sultanas move up and down?When you first put the sultanas into the baking soda and water, they sink because they are heavier than the water around them. When you add vinegar, the chemical reaction produces lots of bubbles of carbon dioxide gas, and some of these bubbles stick to the outside of the sultanas. Because gas is much lighter than water, these bubbles of carbon dioxide gas lift the sultanas up to the surface of the water. But when the sultanas get to the surface, the bubbles of gas burst, so the sultanas become heavy again and sink.RAINBOW MILKEquipment:whole milk (at room temperature)plate (or some other shallow dish with a flat bottom)coloured dyescotton swabsliquid of laundry detergentpaper towelsInstructions:Pour enough milk into the plate so that the bottom is completely covered.Place a few drops of food colouring in the milk (close together works well).Predict what will happen when you touch the tip of a clean cotton swap to the centre of the milk. Test it out by touching the surface of the milk with the swab. It's important not to stir the milk, just touch it with the tip of the cotton swab.Now place a drop of liquid dish soap on the other end of the cotton swap. Touch the soap-covered end in the same area as before. What happens this time?Try touching a few other areas of the milk with the soap-covered swab end. What happens as you continue to touch the milk in other places?The drop of detergent reduces the surface tension at the point where it dissolves the fat molecules in milk. The higher surface tension of the surrounding milk pulls the surface away from that spot, dragging the food dye with it. The rest is due to the detergent breaking down the fats within the milk. As the fat breaks down, water carries the food colouring to where the fat was to fill the space.SELF INFLATING BALLOONS - NEEDS CLOSE SUPERVISIONEquipment:1 balloon containing 1 teaspoon bicarbonate sodafunnel to help with getting the soda in the balloon1 plastic drinking bottle containing a small amount of vinegarInstructions:Place the soda in the balloon.Leaders/Parents help stretch the balloon over the neck of the bottle (leaving balloon hanging so that soda stays in the bottom of the balloon).When all ready, Joeys can tip the balloon up so that soda falls into the balloon.Watch the balloon inflate.When vinegar is mixed with baking soda, they form new substances. One of these is a gas. We call this making of new substances a chemical reaction. The gas is carbon dioxide. If the balloon is securely fastened to the bottle, it will trap the gas. The balloon will inflate as more gas is produced. ................
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