For this activity the children will evaluate the density of different types of liquids and how they react with each other. Give the students an empty 2-liter soda bottle and instruct them to add water, vegetable oil and food coloring. They can add these ingredients in any quantity they choose. Have them replace the lid and shake it up to see what happens. Ask the students to look at how the liquids stayed separate and develop a hypothesis as to why. The science fair display can include the experiment and an explanation of how the different densities of the different liquids reacted together.
For this activity, children will be experimenting with how much light different colors absorb. They will use three different colored t-shirts, such as white, black and yellow, a thermometer and the sunshine. To perform the experiment, have the children lay the shirts out flat in the sunshine. After an hour has passed, they will take the temperature of the air around the shirts and then each of the shirts separately. To take the temperature of the shirts, place the thermometer inside each one for five minutes. Repeat the process for several hours to record sufficient data then create a chart to display at the science fair. The children should be able to answer questions about which shirt was warmest, which was coolest and if any shirt temperatures changed throughout the experiment. They will also want to figure out why these changes occurred.
For this experiment, students will evaluate what makes ice melt at different speeds. They will need three clear glasses and two ice cubes for each. Place the ice cubes into each glass and set them in different spots around the classroom: on a sunny windowsill, in the shade and in a well-lit spot not in the sunlight. Have the children check on the ice melting process every 15 minutes and record their data through pictures. They will record data for one hour to show the progress and how different settings and temperatures affect the ice in the glasses. For the display, they should be able to discuss or answer questions about the speed of the ice melting in different spots and why they think this happened.
This experiment is designed to show children what different colors are in the color black. Start the experiment by laying out four paper coffee filters on newspaper or waxed paper. Have the children draw a large black dot about 2 inches in diameter, colored in, at the center of each filter. With a water dropper, each child will drop three to four drops of water onto the black dot and hold it over the sink for at least 30 seconds to allow the colors to separate. For the fair, the children can bring in their tested filters and create a chart that shows the different colors that they found present in black.