You've been told that you should brush your teeth at least twice a day to prevent cavities. To perform an experiment that tests the effect on teeth of different beverages, you need four teeth, four clear drinking glasses, 1 cup lemon juice, 1 cup apple juice, 1 cup sugar-sweetened cola and 1 cup water. Use the information you already know about what is bad for your teeth to form your hypothesis about what the different liquids will, or won't do to the teeth. Record the date you start the experiment. Describe and number each tooth for your report. Record which number tooth and liquid you put into each glass. Observe the teeth once a week, on the same day and time of the week, and record any changes. Continue the experiment for two months. Did the data support the hypothesis?
Plants need water, sunshine and nutrients from the soil to grow. You can test the effects of watering bean plants with different liquids to see if they are as helpful to the plant as water. Use 14 small pots filled with potting soil, 14 dried lima beans, vinegar, baking soda, sugar, sugar-sweetened cola, orange juice, milk, a graduated cylinder and a ruler. Form your hypothesis about how the different liquids will or won't affect the growth of the bean plants. Record the date you start the experiment. Label two pots, each with the name of one of the liquids to be tested. Label the two remaining pots "Water." The water pots are your controls. Put one bean seed into a shallow hole in the potting soil of each pot. The baking soda, vinegar and sugar must each be put into a solution. For each one, measure and add 75 milliliters of water to 25 milliliters of the substance. Put the pots on a sunny windowsill. Use the same amount of liquid to water the bean plants every other day. Observe the plants daily and note the days you water the plants and record any changes. Measure the plant growth with the ruler. Continue the experiment for six to eight weeks. What were the results, and how did they compare to the hypothesis?
When the air is heated, it expands, or takes up more space. The molecules of air move around more, and bounce off each other more, the higher the temperature rises. The pressure (force) of the heated air also rises. Cooled air compresses, or takes up less space, as the motion of the molecules slows down, and they bounce off each other less often. The air pressure drops. You need two, 2-liter plastic soft drink bottles with caps and access to a freezer for this experiment. Fill both bottles with hot water and allow them to sit for 10 minutes. Pour the water out of the bottles, and put the caps on them. Place one of the bottles in the freezer. Use what you know about heated and cooled air molecules to form your hypothesis of what will happen to the bottles. Allow the bottles to sit for 20 minutes. Open the freezer and take out the bottle. Did either bottle change? Did the results support your hypothesis?
How do you feel when you sit in the sun on a hot day? What about when you sit in the shade? Did you know that dark colors absorb more heat from the sun than light colors? Do an experiment on a hot, sunny day with a large blackboard, three thermometers and a piece of heavy, white paper. Put the blackboard under a shady tree with half of the blackboard in the full sun. Place a thermometer on each half. Place the paper near the blackboard in the sun, and place a thermometer on it. Record the starting temperatures of each thermometer. While you wait 30 minutes, form a hypothesis about which surface will be the hottest and coolest. Check the temperatures and record your results. Did your data support your hypothesis? What color of clothing is best for wearing on a hot, sunny day?