Purchase an ant farm kit, or formicary, from a store and set it up in your classroom, adding in the sand that will be included in the kit. Capture an impregnated queen ant and place it inside your farm to populate it.
Place your formicary in a prominent place in the classroom, such as on a side table, so your young scientists can observe it once each day. Have students draw pictures of the formicary in action once the ant population within is up and running.
Gather students around the ant farm and place a small piece of bread, roughly the size of a bullion cube, at the top of the farm. Get students to observe the ants' caste system as the "worker" ants break up and transport the bread around the formicary.
Educate your first-graders about the process of mummification as used by the Ancient Egyptians. Inform them that you are going to use chemistry to "mummify" an apple.
Add 1/4 cup of salt and 1/2 cup each of bicarbonate of soda and sodium bicarbonate to a zip-loc plastic freezer bag and mix together thoroughly.
Press the shape of a face into the side of an apple using a popsicle stick or the handle-end of a spoon. Insert the popsicle stick or spoon's handle into the bottom of the apple, so it effectively becomes the body to your apple's face.
Place the apple and popsicle stick or spoon into the bag and shake it around to ensure it is submerged in the bag's substances. Place the bag in a warm, dry environment, such as the science laboratory's back room, for 24 hours before removing the apple from the bag. Allow students to draw pictures of the dried-up, shrivelled apple.
Gather your first grade students around the main table or bench in the classroom to demonstrate this simple air pressure experiment. Get students to put on white laboratory coats, which would protect their clothing if they were carrying out the experiment themselves, and goggles to protect their eyes.
Place two plastic identical half-liter bottles on the bench, next to a packet of matches. Explain to your youngsters what happens when a match is struck and how oxygen is a necessary part of burning.
Light one match and carefully lower it into one of the bottles. Place a peeled hard boiled egg with the pointed side downward in the neck of each bottle, one of which now contains a lit match. Ask students to write down on a piece of paper what they think will happen in each of the bottles.
Have students observe until the lit match in one of the bottles consumes the oxygen, thus making it so the air pressure outside the bottle becomes greater than the air pressure inside the bottle. As a result, the egg is pushed inside the bottle because of the air pressure, despite appearing too large to fit through the bottle's neck. The other egg remains in place, as the air pressure is greater within the bottle than outside it.