Observations:
When a toy car made of iron is placed on a glass top and a horseshoe magnet is moved under the glass top, the following observations can be made:

1. The toy car remains stationary: The toy car made of iron does not move or show any signs of attraction or repulsion towards the magnet. It stays in the same position without any noticeable effect.

Explanation:
The observations can be explained based on the properties of the materials involved and the principles of magnetism.

1. Iron is a magnetic material: Iron is a ferromagnetic material, which means it can be magnetized and has magnetic properties. When a magnet is brought close to iron, the iron can become temporarily magnetized and exhibit magnetic behavior.

2. Glass is not magnetic: Glass is not a magnetic material. It does not have any magnetic properties and does not interact with magnets. Therefore, placing the toy car on a glass top does not result in any magnetic effects.

3. Magnetic field lines do not pass through glass: Glass is not permeable to magnetic fields, meaning the magnetic field lines cannot pass through it. Therefore, the magnetic field generated by the horseshoe magnet cannot reach the toy car through the glass top.

4. Magnetic attraction and repulsion: When a magnetic material, such as iron, is brought close to a magnet, it can experience either attraction or repulsion depending on the orientation of the two magnetic fields. However, in this case, since the magnetic field of the magnet cannot reach the toy car through the glass, there is no interaction between them.

Observations:
When the same procedure is repeated with a wooden table top, the following observations can be made:

1. The toy car remains stationary: Similar to the previous case, the toy car made of iron does not move or show any signs of attraction or repulsion towards the magnet. It stays in the same position without any noticeable effect.

Explanation:
The observations remain the same when a wooden table top is used instead of a glass top. This can be explained as follows:

1. Wood is not magnetic: Wood is a non-magnetic material. It does not have any magnetic properties and does not interact with magnets. Therefore, placing the toy car on a wooden table top does not result in any magnetic effects.

2. Magnetic fields do not pass through wood: Wood is not permeable to magnetic fields, similar to glass. Therefore, the magnetic field generated by the horseshoe magnet cannot reach the toy car through the wooden table top.

3. Absence of magnetic interaction: Since the wooden table top does not allow the magnetic field to pass through, there is no interaction between the magnet and the toy car. The magnetic field lines cannot reach the toy car, and hence, there is no attraction or repulsion observed.

Conclusion:
From this activity, it can be understood that magnetic materials, such as iron, can only exhibit magnetic behavior when they come in direct contact with a magnet or when the magnetic field can pass through a material. In the case of the toy car placed on a glass or wooden surface, the magnetic field generated by the horseshoe magnet cannot reach the toy car, resulting in no observable magnetic effects.