Describe the Ghost of Christmas Past's appearance in A Christmas Carol.

To begin, the ghost was "like a child: yet not so like a child as like an old man." The spirit seems to embody the innocence of children and yet possesses the wisdom associated with age: two things we typically do not think of as going together. Usually as we gain wisdom, we lose our innocence. The ghost has long, white hair that hangs down its back, but the "tenderest bloom" on the skin. Its arms are "long and muscular," as though it has a great deal of strength, and yet its legs are "delicately formed." The spirit is certainly a strange combination of old and young. It also wears a tunic of white—again, as if to symbolize its purity and innocence—trimmed with "summer flowers," and it carries a "branch of fresh green holly."

Even more curious is that "from the crown of its head there sprung a bright clear jet of light," and he carries "a great extinguisher" as a hat.  An extinguisher is the small bell-shaped apparatus, usually at the end of a long stick, which one would use to snuff out a candle by placing the bell over the flame and depriving it of air. Finally, Scrooge seems to notice that

its belt sparkled and glittered now in one part and now in another, and what was light one instant, at another time was dark, so the figure itself fluctuated in its distinctness: being now a thing with one arm, now with one leg, now with twenty legs, now a pair of legs without a head, now a head without a body

In other words, it sounds an awful lot like the spirit flickers, like a candle flame, and given the light that comes out of its head and the fact that it carries an extinguisher for a hat, the spirit seems in many ways to resemble a candle. Thus, it embodies all ages, all seasons, and one of the major symbols of goodness and joy in the text: light.  

Describe the scene where the Ghost of Christmas Present appears in A Christmas Carol.

Scrooge was transported to his childhood school.

When the Ghost of Christmas Present first took him back, Scrooge was taken back to a vision of himself as a child.  He remembered it as if it were yesterday.  He enjoyed the vision very much at first, because he saw his old schoolmates and was pleased to see them. 

Then he saw a vision of his former self, a young Scrooge, all alone in the schoolhouse as it was deserted when everyone else went home.  He became quite a bit sadder.

“The school is not quite deserted,” said the Ghost. “A solitary child, neglected by his friends, is left there still.”

Scrooge said he knew it. And he sobbed. (Stave 2)

The reader might be surprised to see some emotion coming out of what before appeared to be an unfeeling Scrooge.  However, Scrooge reacted with sympathy to Marley, and reacted with surprise and glee when he saw the boys.  The shell that Scrooge was around him is beginning to soften.

The visions that the reader sees of a younger Scrooge begin to explain why he is the man he is.  A little boy, all alone in a dreary schoolhouse?  What a sad situation.

[They saw] a long, bare, melancholy room, made barer still by lines of plain deal forms and desks. At one of these a lonely boy was reading near a feeble fire; and Scrooge sat down upon a form, and wept to see his poor forgotten self as he had used to be. (Stave 2)

These visions serve two purposes.  Scrooge is forced to remember how his father used to leave him at school for the holidays, where he had nothing but his books to keep him company.  The reader learns what made him the lonely curmudgeon that he is, and starts to feel some sympathy for him.

Throughout the story, Dickens weaves a picture of Scrooge through the past, the present, and the future.  He will have to face what he was, what he has become, and what might become of him before he can change. In this scene, we see Scrooge just beginning to crack.

In A Christmas Carol, what does the Ghost of Christmas Future look like?

Just a quick response to Michelle Ossa's post. I don't really agree that the Ghost of Christmas Future is the one that affects Scrooge the most emotionally. Sure, it terrifies him, but it's his transformation when re-visiting his childhood and youth, under the influence of the Ghost of Christmas Past, that is his most intense and life-changing experience. This is what sets him on the road to redemption: the re-discovery of old feelings and joys which had been 'long, long forgotten'.  It is like the sudden bursting of a dam of pent-up emotions, which I think is the most poignant aspect of the entire story. It is important to note that he becomes increasingly open and light-hearted from this moment on; he delights in the various displays of Christmas happiness that the Ghost of Christmas Present presents to him, and shows genuine concern for Tiny Tim, and so on.

The interesting thing about the ghost of Christmas future, or the "Ghost of Christmas Yet to Come", is that Dickens refers to it as a phantom rather than a ghost like he did with the other apparitions.

This phantom was perhaps named as such because of how different it was from the others. While the first ghosts interacted and showed some leftover traits of humanity, this one was eerie, silent and quite scary, not only in movement but also in description

It was shrouded in a deep black garment, which concealed its head, its face, its form, and left nothing of it visible save one outstretched hand

The way it moved was just as sinister as it looked

SLOWLY, gravely, silently

The phantom never answers with words, and allows Ebenezer to make his own conjectures every time he asks a question. That psychological dynamic causes more fear and anxiety in Ebenezer than having the actual answers told to him. Moreover, once the finger of the ghost points at something, it does not back down until Scrooge actually looks at what he is pointing.

While he is the phantom Scrooge is more scared of, his ending is quite abrupt and coarse for a ghost so apparently sophisticated.

he saw an alteration in the Phantom's hood and dress. It shrunk, collapsed, and dwindled down into a bedpost.

Therefore the ghost starts out extremely sinister and ends quite coarsely to a point. However, this is undoubtedly the ghost that influenced Scrooge the most, emotionally.

How are the Ghosts of Christmas Past and Present described in A Christmas Carol?

The Ghost of Christmas Past is bright and indistinct, and the Ghost of Christmas Present is jovial and colorful.

Scrooge is a grumpy old miser when his friend Jacob Marley decides to give him a chance to look at his life and make some changes.  Jacob is dead, so his intervention consists of having Scrooge visited by three other ghosts.  Scrooge is skeptical at first, but as he goes along from ghost to ghost he becomes a new man.

The first ghost is very unusual looking.  It seems to shine like a candle, and Scrooge can’t tell whether it is young or old, or male or female.

It was a strange figure—like a child: yet not so like a child as like an old man, viewed through some supernatural medium, which gave him the appearance of having receded from the view, and being diminished to a child's proportions. (Stave 2)

The ghost is old and young at the same time and male and female at the same time because it represents the vague nature of the past.  Sometimes we do not remember things exactly as they happened, so the ghost flickers in and out of focus.  Also, there are many influences on us in our pasts, so that ghost is everyone at one.  The candle-like nature of the ghost represents the glow the past has for us.  Even Scrooge gets teary-eyed at some events from his past.

The Ghost of Christmas Present is very different.  While the first ghost was somewhat reserved and stern, this ghost is friendly and loud.  Even his clothing seems festive.

It was clothed in one simple deep green robe, or mantle, bordered with white fur. This garment hung so loosely on the figure, that its capacious breast was bare … Its feet, observable beneath the ample folds of the garment, were also bare; and on its head it wore no other covering than a holly wreath set here and there with shining icicles. (Stave 3)

One interesting part of this ghost’s appearance is that he wears a scabbard with no sword.  That and his open chest represents his good-nature.  He prefers peace to war.  He is all about celebrating life.  The ghost carries a special torch that he uses to bless those he passes with Christmas spirit.

The second ghost is more friendly than the first, but he does scold Scrooge for not caring about the poor.  He shows Scrooge two children, Ignorance and Want, and tells Scrooge that he should show more compassion.  By the time Scrooge is done with him, he is a changed man.