Any rotating tool has a direction of thrust and a direction of swarf ejection.
It is generally advantageous to have the swarf thrown away from the user, though that involves being able to control the thrust of the tool in a "climb cutting" direction. Climbing is cutting in the direction of rotation, inherently dangerous. Use a right angle handle if possible and develop your arms. Don't grind on the wheel face unless so rated.
A full face shield is recommended, especially if the disc shatters. 4 inchers have a higher RPM than the big boys, less inertia, easier to handle & therefore safer.
Try to never have the disc in a radial plane with your face, always offset.
And again, KNOW where the sparks are going, both for fire protection and prevention of embedment in window glass, etc. Curtains are helpful here.

In direct answer to your question; sparks and shrapnel is what you get using an angle grinder, the metal you are removing has to go somewhere. As you work with metal more you will learn to tell a lot about the type of metal by color and shape of the sparks.

alphonse has given you some good tips on using the tool. I will repeat his most important comment KNOW WHERE THE SPARKS ARE GOING. Using hearing protection is always a good idea and be careful wen you put the tool down. If the disk is still moving it can do damage even if it is not under power.

Angle grinders are great tools. In addition to cutting you can use them to shape metal. I have a friend who builds dinosaurs out of bits of salvage rebar. He shapes the sections of rebar into "bones" using an angle grinder then welds them into a skeleton.

Most angle grinders have a shield that covers a portion of the disk. You should be able to rotate the shield to a position that directs most of the sparks where you want them to go.

A less dramitic tool for cutting up scrap is a reciprocating saw (Sawzall is the brand most people think of). It is not as fast as an angle grinder and no sparks, but a useful alternative. And then there is an oxygen/acetylene rig ........

I love to encourage people to collect tools.

Again --- helpful tips ! Alphonse ... your suggestions are priceless . I'll admit - my arms hurt like heck the day after I cut up that table. Once I get alittle strength - I should be able to manipulate that grinder . ( I also moved those cars away from my area ! ) Blindstar ... I Learned last week about hearing protection. For an hour after I came in the house - my ears were ringing. Not good. Besides a full face shield - earplugs will be in my future. Next time I cut - I'm going to really pay attention how to hold the grinder and watch where the sparks go. ( Rotating the shield will help ,too - I never thought of that )

People that work with metal amaze me . I never gave a thought to the color and shape of sparks. I'm still at that newbie stage where I carry a magnet with me when looking at metal - to find steel. My hubby can just look or touch something and know what it is. I have a long way to go ....
I'm glad you 2 are here to help !!

I hereby raise controversy and make the declarative statement that the guard on hand angle grinders should be removed. The only exception being a visit from OSHA by an inspector who has only held a pencil and whose work experience is writing citations.
The guard truly limits the tool's range and is a great thing to catch on the work enabling the grinder to torque itself at the user.
I forgot to mention prior- always stop the disc on the work, or suitable surface (something unable to be flung) before setting the tool down, as alluded to by Blindstar.

I only partially disagree with you. In the spirit of full disclosure- there are no guards on my angle grinders, however, I do lots of stuff I would not recommend to someone starting out. Ignoring OSHA, I think that safe practices are to a certain extent subjective and related to experience and skill levels.

Well, newbies need to crawl first, and I don't advocate unsafe practice in any way. Observing what the tool does is the direct route to control. Common sense says don't try to fight a one horsepower tool unless you can exert more than one horse.
People working at home (non-employee) can indeed ignore OSHA. Simply threw that in having been on the bad side of an OSHA visit. Should be re-named "Agency to eliminate jobs via Outrageous Fines".

Safety first! Gloves, face shield, ear plugs a dust mask and two hands on the tool. Removing a guard is not a very smart thing to do, I have seen at least four metal fabricators (not weekend warriors) get bad cuts by ignoring the above advice.

Safety always. But we will have to disagree whether removing the guard is smart... I too have seen four metalworkers hurt BY the guard.

Hi Alphonse, can you explain how these metalworkers were hurt by the gaurd?

Sure, in each case (one mine) the guard caught on the work or enabled a point of leverage to throw itself back at the user. In my instance it was in a confined space.
Note that in all cases the grinder was capable of driving a 9" wheel,15A, and sometimes powered by DC which provides greater torque.
The smaller grinders aren't so prone though they too kickback.
Guards are fine if the grinder always stays in one position, in one direction, and never gets used on the face.
There's also a correlation between grinder power and human size. I've seen big ol' boys do things with a grinder that would hurt me.