Perform this basic gravity experiment as a class demonstration by gathering your young scientists around a main classroom bench or table. Fill a glass beaker three-fourths full with tap water from a faucet before slowly filling the remainder of the beaker all the way to the brim. Carefully press down an index card on top of the beaker so an air tight gap is formed over the top. Ask your elementary students if it is possible to turn the beaker upside down without the water spilling. Turn the beaker upside down, ensuring the index card is held flush against the top of the beaker, before letting the index card go. The air pressure outside the glass will hold the index card in place, even if you are not touching it, which is stronger than the force of gravity.
Conduct this elementary experiment to investigate the effect of gravity on the growth of plant seedlings. You will need to prepare for this experiment approximately three weeks before you actually carry it out with your students, by setting up two identical plant pots. Fill identical plant pots two-thirds full with the same potting soil before planting a pair of basil seeds in each one. Provide your plants with regular water, such as once every other day, until they have grown to at least 3 inches tall. Label one of your plant pots "side" and place it on its side within a deep baking tray. Allow your elementary scientists to observe the changes in growth that occur over the coming few weeks, including taking photographs or drawing pictures, as the roots of your sideways plant continue to grow in the downward direction of gravity.
Your elementary students will enjoy this gravitational project, which gets them to build bridges between two chairs using hard-backed books. Be sure that you are using old or discarded books, as they can sustain damage during the project. Furthermore, brief your young scientists on the importance of avoiding being struck by falling books in this project. Split your class into groups of four and get them to place two identical chairs 3 feet opposite one another while facing each other. Challenge them to build a bridge between the two using only hard-backed books, with the aim of the project to use as few books as possible. Get young scientists to think about how gravity affects the bridges the groups have built before seeing which group wins your class competition.
Assemble your elementary class around the science laboratory's main table before setting up a device that demonstrates the basic working of gravity. Place two identical drinking glasses next to one another with a gap of about 1 inch between the two. Cut the bottom 2 inches from a candle to expose its wick. Push a sewing needle or wooden skewer through the middle of a candle and place the skewer on the tops of the glasses so the candle resembles a see-saw. Make sure the candle is perfectly balanced, so it sits horizontally on the glasses, before putting a dish beneath each end of the candle on the table. Light the wick at each end of the candle before getting students to predict what will occur — as wax drips from one end, which becomes lighter, the candle pivots toward its heavier end because of gravity. Your experiment candle will pivot like a see-saw until all of the wax is melted.