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| States of Matter |
c.2007 |
| * Materials can be grouped as solids, liquids
* Solids have a fixed shape * Liquids have the shape of their container, flat top * Gases have no shape and they fill the * Solids melt to become liquids * Liquids freeze at low temperatures * Liquids other than water evaporate What is a Solid? When water freezes you cannot always see the crystalline structure that forms as it solidifies. Add some other substances, and the observable characteristics change. When fruit juice is added to water and frozen, the structure of the ice changes and noticeable crystal structures are evident. It is the "impurities" that cause the change. Just by thinking about science, a common summer activity becomes an experience that promotes language and observation skills. Encourage an atmosphere of curiousity and delight, and everyone will enjoy participating in the process from start to delicious finish! • paper cups • popsicle sticks • water • fruit juice • a freezer What to do : Have the children mix water with a can of frozen juice. Pour the mixture into small paper cups (3 oz). Place the filled cups on a tray, then put them in the freezer. Also freeze a cup of water. Look at the mixture about every 15 minutes. Talk with the children. Encourage them to describe what they see. When the mixture starts to harden, remove the cups from the freezer and have the children place a popsicle stick handle into each cup. Put the cups back into the freezer. Be sure to let the children see the crystals that are starting to form. Continue to check on the progress, talking about the changes that are occurring. When the juice has frozen, remove the cups and give one to each child. Have the children peel the paper cup away from the popsicle. Observe the frozen crystals. Talk about the designs you see. Have a bite. As the children enjoy the treat, show them the water popsicle and talk with them about differences and similarities they notice. How did the water change when juice was added. What do you think will happen to your crystal popsicle if you don't eat it? Try freezing other edible liquids. Compare the different crystal patterns. Freeze bananas and grapes. Talk about similarities and differences. What happens when popsicles or fruit thaw? Are they the same or have they changed? Melting Solids Colour some water (using food colouring) and freeze it in containers - balloons work well. When frozen, take the ice out of the balloons / containers and put them in a water trough. Allow the children to feel the ice and discuss it, as well as discussing the colour mixing which takes place. The results of the colour mixing could then be used in their art work, when mixing paints. This activity could also be used as the stimulus for further work on how materials (in this case water) changes when heated or cooled. Although the age range 5-7 is specified, this activity is great for all ages really - a fun, hot day, learning experience. MOLECULES ON THE MOVE Rinse, dry and save all equipment when done. When you put food color in water, it would just sit there if nothing in the water were moving. When we use hot water, the food color mixes faster because the molecules are moving faster. Be sure to remind the kids to not bump or stir their beakers or the food color will mix into the water due to this physical disturbance. This is the first "chemistry experiment" so it is a good time to review measurement technique and the need to rinse equipment between and after use. Accurate measurement of the volume of solids requires that the solid be level in the measuring spoon or cup. Use a plastic straw or stir stick for leveling. Accurate measurement of the volume of liquids requires that the cup be placed on a flat surface (desk top) and that the kids get their eyes level with the top of the liquid when making the measurement. Be sure to rinse stir sticks, measuring cups, etc. after each use and especially before using them for a second substance! Also, remind the kids that they should always explain their answers even if they are not explicitly asked for an explanation. DEDUCING DENSITY Use: Dark corn syrup (brown) , Dish washing detergent (blue or green) , Water with food coloring (green or blue) , Vegetable oil Teach the kids how to pour two chemicals together: hold a stick inside the jar with its tip touching the inside wall of the jar. Pour the liquid on the stick. If you pour slowly, the liquid will run down the stick and then down the side of the jar. Remind the kids to never pour extra chemicals back in the bottle. Throw them away. For jars, use disposable water bottles with the tops cut off. These are plastic (unbreakable), clear, and have a small diameter so they require less of the liquids to make a thick layer. RATE OF EVAPORATION Each team fills 3 identical jars with 3 liquids: rubbing alcohol, water, liquid soap and observes over a day or two how they evaporate. You need 1/8 cup per team of each liquid so, for a class of 20, you need 3 cups (24 oz) of each to allow for some extra. Be sure the kids rinse the jars well when they are done. I don't use oil because it is so messy to clean up well. Evaporation Painting with salt water. • 1/4 cup salt • paper for painting on • containers for paint • 1/4 cup warm water • paint brushes • food colouring • measuring cups Measure the salt into a container. Add the warm water to the salt. Add several drops of food coloring to the mixture. (make more of the mixture if you would like more colours, or split this mixture into seperate containers for more colours) Paint a picture with the mixture. Let the paintings to dry overnight. (The water will evaporate from the painting and the colored salt will stay on the paper) Have a discussion on what happened to the paintings. Think of some reasons why this might have happened. |
| Prop Box Resources Include the following collections of objects and materials for children to create, discover, and use for imaginary play. Store collections in boxes or baskets to be accessible at any time (indoors or outdoors) for children to enhance their play. various jars and clear containers water source food colouring |
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| "To the world you might be one person, but to one person you
might be the world." ~ Author unknown ~ |
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