Cut two apples into slices and place on two plates. Add lemon juice
 to one of the plates of slices and observe the apples throughout the day.

Take a field trip to an apple orchard if possible.

Provide three types of apples - red, yellow, and green.  Wash the apples and cut them
 into pieces, and place on three separate paper plates.  Tell children the name of each
 apple.  Have them compare the color, texture, and taste of each type of apple.

Give each child an apple. Ask them to describe the apple using all their
senses except taste. Then cut the apple in half - explain that they grow from
seeds. Point out the various parts - invite them to count the seeds - cut the
apple into bite size pieces - let them eat a piece and describe how the apple tastes.

Provide small paper drinking cups, apple seeds, potting soil or dirt, and water.
Save seeds from the apples used from a apple food experience.  Give each child
 a cup and have the children fill their cups with soil.  Place finger in soil to make
  a small hole and drop in the seed.  Dampen the soil with a small amount of water.
  Place cups in well lighted area and water occasionally; then read
 the children the book The Tiny Seed by Eric Carle.

This mini-booklet gets down to the core of apple science!  To make one, fold a 9" x 6"
 piece of red construction paper in half; then trace an apple shape onto the paper as
 shown.  Cut the apple shape through both thicknesses of paper, leaving part of the fold
 intact.  Provide a child with the apple cutout and an apple half.  Invite the child to
 examine the inside of the apple.  Then direct the child to open the apple cutout,
 dip the apple half in white paint, and then make prints on the insides of the cutout.
  When the paint is dry, have the child glue seeds onto the apple prints.
  What's inside an apple?  Open up the booklet and "see-d"!

Use magnifying glasses and look at apples and apple seeds.  With the magnifying
 glass, encourage the children to look at seeds inside and outside of an apple.  

Compare dry apple slices to raw apple slices - write observations on chart paper.

Observe and discuss with the children what raw apples look like.  Ask them to predict what will happen when
 the apples are cooked.  Bake a whole apple.  Slice and simmer another one.  Have the children compare the
 results with the raw apples.  Ask the to describe the changes that occurred in color, texture, and taste

Set up an apple activity center.  Provide a variety of items for the children to explore such as red,
 green, and yellow apples; apple seeds to examine with a magnifying glass;
 and foods made with apples (apple sauce, dried apples, and apple juice.)

Ask the children to compare apple seeds with other fruit seeds that you have set out.

Show the children three apples -- one red, one green, one yellow. Discuss how all apples are different on
 the outside but the same inside. Take a large bowl of water. Ask the children what will happen to an apple
 or a carrot in the bowl. Place the carrot in first; then remove it and put in the apple. Carrot matter is very
 tightly packed & it will sink. The apple contains allot of air & it is not packed as tightly which will allow
 it to float. Before cutting open the apple ask kids to predict how many seeds will be inside.
 Cut the apple in half horizontally & look at the "star" that holds the seed.

Cut an apple in half crosswise to show design of the seeds. How are they formed?
 What do they look like? Ask children questions about the apple such as: What design
does the apple make? Were you surprised? Do you think any other fruit has a special shape inside it?

Line two paper cups with black construction paper. Place one apple slice in each cup.
 Make sure the apple slices are similar in size. Cover the cups with plastic wrap. Use
 rubber bands. Roll two pieces of white paper into cones. Line of the cones with aluminum
foil. Place an apple inside each cone. Place both cones on newspaper in direct sunlight.
 Make sure they are facing the sun. Check the apples every
 30 minutes to see which slice is cooking the fastest.

Display different types of apples. These include Granny Smith, Yellow Delicious,
 Red Delicious, Macintosh, etc. Add a magnifying glass; and foods made
 with apples (applesauce, dried apples, apple juice, etc.) for more exploration.

Observe and discuss with the children what raw apples look like. Ask them to predict what will happen when
 the apples are cooked. Bake a whole apple. Slice and simmer another one. Have the children compare the
 results with the raw apples. Ask them to describe the changes that occurred in color, texture, and taste. Also
 leave a cut apple out, put one cut apple in a baggie, and try putting cut apples in other places--what happens?

Materials Needed:
black and white pictures of an apple seed,
the start of an apple tree,
an apple tree (with no apples) and an apple tree with apples,
(These pictures can be easily drawn and copied)
crayons, and construction paper, scissors, glue

Directions:
After discussing with the children the growth of an apple, have them color their
 sequencing pictures, cut them out and paste them on their construction paper in order

Display different types of apples. These include Granny Smith, Yellow Delicious,
 Red Delicious, Macintosh, etc. Add a magnifying glass; and foods made with apples
 (applesauce, dried apples, apple juice, etc.) for more exploration. You may also compare
 seeds of the apple vs. seeds of other fruits. Provide a magnifying glass for this activity as well.

Pre-K Fun Theme Pages are for educational reference only! 
No copyright infringement is intended.
I do not claim any of these as my own ideas.  
They are shared from friends and fellow group members.  
Thanks for sharing all your great ideas!